INTERNATIONAL VENUS WORKSHOP ABSTRACT LIST Monday, 10th June Schedule
Author
9:00 - 13:00
Title
SWT
9:00 - 13:00
Science Working Team meeting (only for the Venus Express team members)
14:30
Session
Surface/Interior
14:30 - 15:00
Stofan
Venus: Earth’s (Neglected) Twin (Invited)
15:00 - 15:15
Mueller
Search for active lava flows with VIRTIS on Venus Express
15:15 - 15:30
Shalygin
Venus surface geology from near infrared night side Venus Monitoring Camera
images
15:30 - 16:00
Smrekar
Diverse Geologic Settings of Recent Volcanism on Venus and
Implications for the Interior (Invited)
Coffee
16:00 - 16:30
16:30
Session
Surface/Interior
16:30 - 17:00
Sotin
Are terrestrial exoplanets Earth-like, Venus-like, or different? (Invited)
17:00 - 17:15
Ghail
The influence of rheology and volatiles on the geology of Venus
17:15 - 17:45
Russell
Venus and Planetary Magnetism (Invited)
Luhmann
Large-scale magnetic flux ropes in low-altitude ionosphere of Venus: planetary
origin or solar wind origin
17:45 - 18:00
18:00 - 18:15
18:15 - 19:45
Discussion of Surface/Interior/Magnetism
Poster session 1
Tuesday, 11th June Schedule
9:00
Author
Title
Session
Plasma & Induced Magnetosphere
9:00 - 9:30
Zhang
Physics of Induced Magnetosphere (Invited)
9:30 - 10:00
Luhmann
Comparative Plasma Interactions and their Effects at Venus, Mars and
Titan (Invited)
10:00 - 10:15
Barabash
How the near-Venus space affects the planet
10:15 - 10:30
Stenberg
Ion escape from Venus
10:30 - 10:45
Masunaga
Dependence of O+ escape rate from the Venusian upper atmosphere on IMF
directions: ASPERA-4 observations
10:45 - 11:00
McEnulty
Comparisons of Venus Express measurements with an MHD model of O+ ion
flows: Implications for atmosphere escape measurements
Session
Plasma & Induced Magnetosphere
11:30 - 11:45
Lundin
Solar Wind energy and momentum transfer - Effects on the Venus polar
thermosphere
11:45 - 12:00
Fedorov
The plasma vortex in the Venusian plasma tail. Steady-state reconnection or fluid
motion?
12:00 - 12:15
Nordheim
Cosmic ray ionization in the Venusian atmosphere from Monte Carlo modelling
12:15 - 12:30
Dubinin
Ionospheric magnetic fields and currents at Mars and Venus
12:30 - 12:45
Vasko
Fine structure of the Venus current sheet
12:45 - 13:00
Coates
Ionospheric photoelectron observations at Venus
13:00 - 13:15
Gray
A survey of Hot Flow Anomalies at Venus
13:15 - 13:30
Russell
The Implications of the Observed Evolution of the Co-Orbiting Material in 2201
Coffee
11:00 - 11:30
11:30
PROGRAM – PAGE A Oljato’s Orbit Observed by PVO and VEX
Lunch
13:30
15:30
Etna excursion
Wednesday, 12th June Schedule
9:00
Author
Title
Session
Dynamics & Structure
9:00 - 9:25
Lebonnois
Venus GCM modelling: current status and perspectives in the light of Venus
Express datasets (Invited)
9:25 - 9:50
Rodin
Non-hydrostatic general circulation model of the Venus atmosphere (Invited)
9:50 - 10:05
Takagi
Structures and generation mechanisms of the Venus atmospheric superrotation
10:05 - 10:20
Sugimoto
Baroclinic modes in the Venus atmosphere simulated by AFES (Atmospheric GCM For the
Earth Simulator)
10:20 - 10:35
Limaye
Global Vortex Circulation on Venus - an assessment from Venus Express Observations
10:35 - 10:50
Hueso
Measurements of Venus winds from ultraviolet, visible and near infrared images with
VIRTIS on Venus Express
10:50 - 11:05
Bertaux
Atmospheric Oscillation in the atmosphere of Venus: the Cupido effect
Session
Dynamics & Structure
11:30 - 11:45
Lee
Variations of the radiative forcing induced by the cloud top structure changes of the
Venus mesosphere
11:45 - 12:00
Grassi
Thermal Structure of Venus Mesosphere as Observed by VIRTIS - Venus Express
12:00 - 12:15
Zasova
Thermal structure of the Venus mesosphere from remote sensing in the infrared spectral
range (VIRA II improvement)
12:15 - 12:30
Tellmann
The VeRa Radio Occultation Data Base: Atmosphere and Ionosphere (Invited)
12:30 - 12:45
Tellmann
Waves in the Venus Atmosphere detected by the Venus Express Radio Science
Experiment VeRa (Invited)
12:45 - 13:00
Migliorini
Gravity waves in the Venus upper atmosphere, modelled on VIRTIS/Venus Express data
Coffee
11:05 - 11:30
11:30
Lunch
13:00 - 14:30
Session
Upper Mesosphere/Lower Thermosphere
14:30 - 14:45
14:30
Piccialli
Thermal structure of the upper atmosphere of Venus with SPICAV/VEx data
14:45 - 15:00
Mahieux
CO2 rotational temperatures compared to hydrostatic temperatures obtained with the
SOIR instrument on board VEx
15:00 - 15:15
Zalucha
Incorporation of a gravity wave momentum deposition parameterization into the Venus
thermosphere general circulation Model (VTGCM)
15:15 - 15:30
Lopez-Valverde
Retrieval of temperature and carbon monoxide from the 4.7um limb non-LTE emission of
the upper atmosphere measured by VIRTIS/Venus Express
15:30 - 15:45
Sornig
Earth based Doppler-wind and temperature measurements in Venus upper atmosphere
using the infrared heterodyne spectrometer THIS
15:45 - 16:00
Clancy
Doppler Winds Mapped around the Lower Thermospheric Terminator of Venus: JCMT
Observations of the 2012 Solar Transit
16:30
Session
Upper Mesosphere/Lower Thermosphere
16:30 - 16:45
Bertaux
Venus night side measurements of winds at 115 km altitude from NO bright patches
tracking
16:45 - 17:00
Stiepen
Venus nitric oxide nightglow distribution: a clue to thermospheric dynamics
17:00 - 17:15
Zasova
The O2 nightglow from VIRTIS-M VEX measurements
17:15 - 17:30
Gérard
Latitudinal variations of the altitude of the Venus O2 airglow observed with VIRTIS-M: a
Coffee
16:00 - 16:30
PROGRAM – PAGE B signature of dynamical processes in the upper atmosphere
17:30 - 17:45
Jain
Modelling of ultraviolet and visible dayglow emissions on Venus
17:45 - 18:00
Clarke
Coordinated Sounding Rocket, HST, and SPICAV Observations of Venus in Nov. 2013
18:00 - 18:15
18:15 -19:45
Discussion of airglow and dynamics
Poster session 2
Thursday, 13th June Schedule
9:00
Author
Title
Session
Chemistry & Composition
9:00 - 9:15
Encrenaz
Ground-based observations of minor species on Venus using infrared
spectroscopy (Invited)
9:15 - 9:30
Encrenaz
Sulfur and water mapping in the mesosphere of Venus
9:30 - 9:45
Marcq
Measurements of minor species at cloud top level
9:45 - 10:00
Fedorova
Water vapor and the cloud top variations in the Venus’ mesosphere from SPICAV
observations
10:00 - 10:15
McGouldrick
Re-analysis of Pioneer Venus SO2 measurements
Grinspoon
Assessing An Impact Hypothesis for Upper Atmosphere Abundance Variations on
Venus
10:15 - 10:30
Coffee
10:30 - 11:00
11:00
Session
Chemistry & Composition
11:00 - 11:15
Sandor
Positive Correlation of SO, SO2 in the Dayside Venus Mesosphere: Identification of
Diurnal SOx Partitioning from JCMT Submm Spectroscopy
11:15 - 11:30
Sandor
Temporal, Spatial Variation of HCl in the Venus Mesosphere, based upon Submm
Spectroscopic Observations with JCMT
11:30 - 11:45
Vandaele
Trace gases in the mesosphere and lower thermosphere of Venus from
SOIR/VEX (Invited)
11:45 - 12:00
Vandaele
Contribution of the SOIR/VEX instrument to VIRA II (Invited)
12:00
Session
Clouds & Hazes
12:00 - 12:30
Wilquet
SPICAV-SOIR mesospheric aerosols observations and modeling (Invited)
12:30 - 12:45
Titov/Markiewicz
Venus cloud morphology: monitoring by the VMC/ Venus Express camera continued
12:45 - 13:00
Petrova
Physical properties of particles in the upper clouds of Venus from the IR and UV
images taken by VMC/VEx at small phase angles
Session
Clouds & Hazes
14:30 - 15:00
Hashimoto
Temporal variation of UV reflectivity of Venus: VEX/VMC data analysis
(Invited)
15:00 - 15:15
Esposito
Causes of the bright and dark features at the Venus cloud tops
15:15 - 15:30
Satoh
On the origin of the 1-micron contrast features in Venus clouds
15:30 - 15:45
Maattanen
Modeling the clouds on Venus: model development and improvement of a nucleation
parameterization
15:45 - 16:00
Imamura
Latitudinal and local time dependence of Venus's cloud-level convection
16:00 - 16:15
Ignatiev
Cloud top variations from Venus Express measurements (Invited)
16:15 - 16:30
Ignatiev
Venus Clouds: Input to VIRA II model from Venus Express and Venera 15
measurements (Invited)
Lunch
13:00 - 14:30
14:30
16:30 - 16:45
Discussion of chemistry and clouds
Coffee
16:45 - 17:15
17:15
Session
Lab-based
17:15 - 17:40
Helbert
High temperature spectroscopy at the Planetary Emissivity Laboratory in
PROGRAM – PAGE C support of present and future Venus missions" (Invited)
17:40 - 18:05
Slanger
Long-lived Emitters in the Atmospheres of the Terrestrial Planets (Invited)
18:05 - 18:30
Hartmann
Experimental and theoretical studies of CO2 infrared absorption continua
(Invited)
18:30 - 18:45
Kohler
Experimental Stability of Tellurium: Implications for the Venusian Radar Anomalies
18:45 - 19:00
Stefani
Experimental set-up to study optical properties of gases at typically planetary
conditions
19:00 - 19:15
Snels
Carbon dioxide collision induced absorption in the 1.18 micron atmospheric window of
Venus
20:00
Team dinner
Friday, 14th June Schedule
Author
Title
9:00
Session
Evolution
9:00 - 9:25
Moresi
The influence of surface conditions on global mantle evolution (Invited)
9:25 - 9:40
Gillmann
Long term evolution of Venus through Mantle/Atmosphere coupling
9:40 - 9:55
Lebrun
Thermal evolution of an early magma ocean in interaction with the atmosphere:
conditions for the condensation of a water ocean
9:55 - 10:10
Marcq
Early evolution of telluric atmospheres in the magma ocean stage
10:10 - 10:25
Taylor
Volcanism and Climate on Venus: An Updated Model
10:25 - 10:50
Goldblatt
New calculations of the runaway greenhouse limit: bad news for early
Venus and future Earth (Invited)
10:50 - 11:05
Baines
The origin and early evolution of Venus, Earth and Mars: Clues from bulk properties
and the abundances and isotopic ratios of noble and light gases
Coffee
11:05 - 11:30
11:30
11:30 - 11:45
Future
Nakamura
Japan/Akatsuki report
11:45 - 12:00
Zasova
Russia/Venera-D report
12:00 - 12:15
Limaye/Baines
U.S./VEXAG report
12:15 - 12:30
Drossart
Future Venus IR observation plans
12:30 - 12:45
All
ISSI/EuroVenus/other reports
12:45 - 13:00
Taylor
Venus III book discussions
13:00 - 13:15
Zasova
VIRA II discussion
13:15 - 13:30
Wilson
Future VEx science plan
13:30 - 14:00
All
Discussion
14:00
End
PROGRAM – PAGE D GROUP 1 POSTER – MON‐WED Author
Title
Cochrane
Errors and Artifacts in the Magellan Imagery of the Surface of Venus
Nunes
Stereo-Derived Topography To Aid Emissivity Estimates at Tesserae on Venus
Peter
A global comparison between VeRa radio science observations of the Venus dayside
ionosphere and the IonA model
Russell
ULF and ELF Electromagnetic Waves in the Venus Ionosphere: Separating Atmospheric and
Magnetosheath Sources
Stenberg
Solar wind precipitation on Venus
Molaverdikhani
A new dawn-dusk asymmetry in the photoelectron flux of Venus’s Ionosphere
Ogohara
Limb fitting and cloud tracking for the study of the Venus atmosphere
Widemann
Mesospheric Temperature at Terminator using SDO/HMI Aureole Photometry, DST/FIRS
CO2 absorption spectroscopy and comparison with Venus Express
Ando
Vertical structure of the Venus vortex
Fukuhara
Temperature variation of the cloud top of Venus obtained by photometry observation by LIR
onboard Akatsuki
Piccialli
Gravity waves in Venus mesosphere observed by the Venus Monitoring Camera on board
Venus Express
Marinangeli
Polar Vortex: a common element of the Earth and Venus
Peralta
Towards a general classification of atmospheric waves on Venus
Yamamoto
Simulation of Venus’ polar vortex in the presence of diurnal thermal tide
Machado
Venus cloud tops winds with ground-based Doppler velocimetry and comparison with cloud
tracking method
Soret
The time evolution of O2(a1Δ) individual observations acquired by VIRTIS-M on board Venus
Express
Svedhem
The variable upper atmosphere of Venus - data from drag and torque measurements by
Venus Express
López-Valverde
Mapping the lower thermosphere of Venus using VIRTIS/VEx Nadir non-LTE observations at
4.3 um
Migliorini
Visible and Infrared nightglow investigation in the Venus atmosphere by means of VIRTIS on
Venus Express
García-Muñoz
Global imaging of the Venus O2 visible nightglow with the Venus Monitoring Camera
Gray
The Effect of Coronal Mass Ejections and Solar Flares on the Venusian Nightglow
Anderson
Mt. Etna and the Eistla volcanoes: Comparative studies to constrain venusian volcano
evolution and flow emplacement
Bougher / Parkinson
Temperatures in Venus' Lower Thermosphere: Comparison of VTGCM and SOIR Profiles at
the Terminator
PROGRAM – PAGE E GROUP 2 POSTER – WED‐FRI Author
Title
Fedorova
Observations of the near-IR nightside windows of Venus during Maxwell Montes transits by
SPICAV IR onboard Venus Express
Iwagami
Ground-based IR observation of oxygen isotope ratios in the Venus atmosphere
Oschlisniok
Abundance of sulfuric acid vapor in the Venus atmosphere derived from the Venus Express Radio
Science Experiment VeRa
Cottini
Water vapor near the cloud tops of Venus from VIRTIS Venus Express day side data
Lorenz
On the Possibility of Gamma Ray Flashes from Venusian Lightning
Mills
Modeling and observations of mesospheric sulfur chemistry
Robert
Spectral inventory of the SOIR spectra onboard Venus Express
Stolzenbach
Three-dimensional modelling of Venus photochemistry
Jessup
Variations in Venus’ cloud top SO2 and SO gas density with latitude and time of day
Politi
VIRTIS-VEX data analysis for the study of the Venus
Carlson
Progress in a refined calibration of the Venus Express VIRTIS-M instrument with application to
Venus’s ultraviolet absorber
Enomoto
Venusian upper hazes observed by Imaging-Polarimetry system HOPS
Kuroda
Latitudinal cloud structure in the Venusian northern hemisphere evaluated from Venus
Express/VIRTIS observations
Rossi
Study of Venus cloud layers by polarimetry using SPICAV/VEx
Takagi
High-altitude source for the Venus’ upper haze found by SOIR/Venus Express
Takeshi
Simulation of the formation, evaporation and transport of sulfuric acid clouds on Venus using a
general circulation model
Cimo
Planetary Radio Interferometry and Doppler Experiments for current and future Venusian
missions
Molera Calves
Interplanetary scintillations study retrieved from Venus Express communications signal
Pluchino
Using Venus Express to perform sounding experiments on lunar ionosphere
Rafkin
A compact, Low Power Tunable Laser Spectrometer for Trace Gas Measurement in the Venus
Atmosphere
Rodin
A compact, lightweight infrared heterodyne spectrometer for studies of Venus atmosphere
Perez-Hoyos
Analysis of MESSENGER/MASCS data during second Venus flyby
PROGRAM – PAGE F Index Authors
Anderson
Ando
Title
Mt. Etna and the Eistla volcanoes: Comparative studies to constrain venusian volcano
evolution and flow emplacement
Vertical structure of the Venus vortex
Page
48
42
Baines
The origin and early evolution of Venus, Earth and Mars: Clues from bulk properties
and the abundances and isotopic ratios of noble and light gases
36
Barabash
How the near-Venus space affects the planet
5
Bertaux
Atmospheric Oscillation in the atmosphere of Venus: the Cupido effect
12
Bertaux
Venus night side measurements of winds at 115 km altitude from NO bright patches
tracking.
Bougher / Parkinson Temperatures in Venus' Lower Thermosphere: Comparison of VTGCM and SOIR
Profiles at the Terminator
Carlson
Progress in a refined calibration of the Venus Express VIRTIS-M instrument with
application to Venus’s ultraviolet absorber
Cimo
Planetary Radio Interferometry and Doppler Experiments for current and future
Venusian missions
Clancy
Doppler Winds Mapped around the Lower Thermospheric Terminator of Venus: JCMT
Observations of the 2012 Solar Transit
Clarke
Coordinated Sounding Rocket, HST, and SPICAV Observations of Venus in Nov. 2013
19
48
53
56
19
21
Coates
Ionospheric photoelectron observations at Venus
8
Cochrane
Collinson
Errors and Artifacts in the Magellan Imagery of the Surface of Venus
A survey of Hot Flow Anomalies at Venus
39
Cottini
Drossart
Water vapor near the cloud tops of Venus from VIRTIS Venus Express day side data
Future Venus IR observation plans
51
Dubinin
Ionospheric magnetic fields and currents at Mars and Venus
8
Encrenaz
Encrenaz
Ground-based observations of minor species on Venus using infrared spectroscopy
Sulfur and water mapping in the mesosphere of Venus
23
Enomoto
Esposito
Venusian upper hazes observed by Imaging-Polarimetry system HOPS
Causes of the bright and dark features at the Venus cloud tops
54
Fedorov
The plasma vortex in the Venusian plasma tail. Steady-state reconnection or fluid
motion?
Water vapor and the cloud top variations in the Venus’ mesosphere from SPICAV
observations
Observations of the near-IR nightside windows of Venus during Maxwell Montes
transits by SPICAV IR onboard Venus Express
Temperature variation of the cloud top of Venus obtained by photometry observation
by LIR onboard Akatsuki
Global imaging of the Venus O2 visible nightglow with the Venus Monitoring Camera
Latitudinal variations of the altitude of the Venus O2 airglow observed with VIRTISM: a signature of dynamical processes in the upper atmosphere
Fedorova
Fedorova
Fukuhara
García-Muñoz
Gérard
9
38
23
28
7
24
50
42
47
21
Ghail
The influence of rheology and volatiles on the geology of Venus
3
Gillmann
Long term evolution of Venus through Mantle/Atmosphere coupling.
34
Goldblatt
New calculations of the runaway greenhouse limit: bad news for early Venus and
future Earth
Thermal Structure of Venus Mesosphere as Observed by VIRTIS - Venus Express
The Effect of Coronal Mass Ejections and Solar Flares on the Venusian Nightglow
Grassi
Gray
Grinspoon
Hartmann
Assessing An Impact Hypothesis for Upper Atmosphere Abundance Variations on
Venus
Experimental and theoretical studies of CO2 infrared absorption continua
Hashimoto
Temporal variation of UV reflectivity of Venus: VEX/VMC data analysis
INDEX ‐ PAGE I 35
13
47
25
32
28
Helbert
Hueso
Ignatiev
Ignatiev
High temperature spectroscopy at the Planetary Emissivity Laboratory in support of
present and future Venus missions"
Measurements of Venus winds from ultraviolet, visible and near infrared images with
VIRTIS on Venus Express
Cloud top variations from Venus Express measurements
31
12
30
Imamura
Venus Clouds: Input to VIRA II model from Venus Express and Venera 15
measurements.
Latitudinal and local time dependence of Venus's cloud-level convection
Iwagami
Ground-based IR observation of oxygen isotope ratios in the Venus atmosphere
50
Jain
Modelling of ultraviolet and visible dayglow emissions on Venus
21
Jessup
Kohler
Kuroda
Variations in Venus’ cloud top SO2 and SO gas density with latitude and time of day
Experimental Stability of Tellurium: Implications for the Venusian Radar Anomalies
Latitudinal cloud structure in the Venusian northern hemisphere evaluated from
Venus Express/VIRTIS observations
53
32
Lebonnois
Venus GCM modelling: current status and perspectives in the light of Venus Express
datasets
Thermal evolution of an early magma ocean in interaction with the atmosphere:
conditions for the condensation of a water ocean
LeBrun
Lee
Limaye
Limaye/Baines
Lopez-Valverde
Variations of the radiative forcing induced by the cloud top structure changes of the
Venus mesosphere
Global Vortex Circulation on Venus - an assessment from Venus Express
Observations
U.S. / VEXAG report
30
29
54
10
34
13
11
37
Marcq
Retrieval of temperature and carbon monoxide from the 4.7um limb non-LTE
emission of the upper atmosphere measured by VIRTIS/Venus Express
Mapping the lower thermosphere of Venus using VIRTIS/VEx Nadir non-LTE
observations at 4.3 um
On the Possibility of Gamma Ray Flashes from Venusian Lightning
Large-scale magnetic flux ropes in low-altitude ionosphere of Venus: planetary origin
or solar wind origin
Comparative Plasma Interactions and their Effects at Venus, Mars and Titan
Solar Wind energy and momentum transfer - Effects on the Venus polar
thermosphere
Modeling the clouds on Venus: model development and improvement of a nucleation
parameterization
Venus cloud tops winds with ground-based Doppler velocimetry and comparison with
cloud tracking method
CO2 rotational temperatures compared to hydrostatic temperatures obtained with the
SOIR instrument on board VEx
Measurements of minor species at cloud top level
Marcq
Marinangeli
Early evolution of telluric atmospheres in the magma ocean stage
Polar Vortex: a common element of the Earth and Venus
Masunaga
Dependence of O+ escape rate from the Venusian upper atmosphere on IMF
directions: ASPERA-4 observations
Comparisons of Venus Express measurements with an MHD model of O+ ion flows:
Implications for atmosphere escape measurements
6
McGouldrick
Re-analysis of Pioneer Venus SO2 measurements
25
Migliorini
Gravity waves in the Venus upper atmosphere, modelled on VIRTIS/Venus Express
data
Visible and Infrared nightglow investigation in the Venus atmosphere by means of
VIRTIS on Venus Express
Modeling and observations of mesospheric sulfur chemistry
López-Valverde
Lorenz
Luhmann
Luhmann
Lundin
Maattanen
Machado
Mahieux
McEnulty
Migliorini
Mills
Molaverdikhani
Molera Calves
A new dawn-dusk asymmetry in the photoelectron flux of Venus’s Ionosphere
Interplanetary scintillations study retrieved from Venus Express communications
signal
INDEX ‐ PAGE II 18
46
51
3
5
7
29
44
17
24
35
43
6
16
46
52
41
56
Moresi
The influence of surface conditions on global mantle evolution
Mueller
Search for active lava flows with VIRTIS on Venus Express
1
Nakamura
Japan / Akatsuki report
36
Nordheim
Cosmic ray ionization in the Venusian atmosphere from Monte Carlo modelling
7
Nunes
Stereo-Derived Topography To Aid Emissivity Estimates at Tesserae on Venus
Ogohara
Oschlisniok
Limb fitting and cloud tracking for the study of the Venus atmosphere
Abundance of sulfuric acid vapor in the Venus atmosphere derived from the Venus
Express Radio Science Experiment VeRa
39
41
Peralta
Perez-Hoyos
Towards a general classification of atmospheric waves on Venus
Analysis of MESSENGER/MASCS data during second Venus flyby
Peter
A global comparison between VeRa radio science observations of the Venus dayside
ionosphere and the IonA model
Physical properties of particles in the upper clouds of Venus from the IR and UV
images taken by VMC/VEx at small phase angles
Petrova
Piccialli
Thermal structure of the upper atmosphere of Venus with SPICAV/VEx data
Piccialli
Gravity waves in Venus mesosphere observed by the Venus Monitoring Camera on
board Venus Express
Using Venus Express to perform sounding experiments on lunar ionosphere
VIRTIS-VEX data analysis for the study of the Venus
Pluchino
Politi
Rafkin
34
50
44
58
39
28
16
43
57
53
Robert
A compact, Low Power Tunable Laser Spectrometer for Trace Gas Measurement in
the Venus Atmosphere
Spectral inventory of the SOIR spectra onboard Venus Express
52
Rodin
Non-hydrostatic general circulation model of the Venus atmosphere
10
Rodin
Rossi
A compact, lightweight infrared heterodyne spectrometer for studies of Venus
atmosphere
Study of Venus cloud layers by polarimetry using SPICAV/VEx
Russell
Venus and Planetary Magnetism
Russell
The Implications of the Observed Evolution of the Co-Orbiting Material in 2201
Oljato’s Orbit Observed by PVO and VEX
ULF and ELF Electromagnetic Waves in the Venus Ionosphere: Separating
Atmospheric and Magnetosheath Sources
Positive Correlation of SO, SO2 in the Dayside Venus Mesosphere: Identification of
Diurnal SOx Partitioning from JCMT Submm Spectroscopy
Russell
Sandor
Sandor
57
57
55
3
9
40
25
Temporal, Spatial Variation of HCl in the Venus Mesosphere, based upon Submm
Spectroscopic Observations with JCMT
On the origin of the 1-micron contrast features in Venus clouds
Venus surface geology from near infrared night side Venus Monitoring Camera
images
Abstract Nr. O-014, Slanger, Tom, Long-lived Emitters in the Atmospheres of the
Terrestrial Planets
Diverse Geologic Settings of Recent Volcanism on Venus and Implications for the
Interior
Carbon dioxide collision induced absorption in the 1.18 micron atmospheric window
of Venus
The time evolution of O2(a1Δ) individual observations acquired by VIRTIS-M on
board Venus Express
Earth based Doppler-wind and temperature measurements in Venus upper
atmosphere using the infrared heterodyne spectrometer THIS
18
Sotin
Are terrestrial exoplanets Earth-like, Venus-like, or different ?
2
Stefani
Experimental set-up to study optical properties of gases at typically planetary
conditions
Ion escape from Venus
Satoh
Shalygin
Slanger
Smrekar
Snels
Soret
Sornig
Stenberg
INDEX ‐ PAGE III 26
29
1
31
2
33
45
33
6
Stenberg
Solar wind precipitation on Venus
Stiepen
Venus nitric oxide nightglow distribution: a clue to thermospheric dynamics
20
Stofan
Venus: Earth’s (Neglected) Twin
1
Stolzenbach
Three-dimensional modelling of Venus photochemistry
52
Sugimoto
Takagi
Baroclinic modes in the Venus atmosphere simulated by AFES (Atmospheric GCM For
the Earth Simulator)
The variable upper atmosphere of Venus - data from drag and torque measurements
by Venus Express
Structures and generation mechanisms of the Venus atmospheric superrotation
Takagi
High-altitude source for the Venus’ upper haze found by SOIR/Venus Express
Takeshi
Taylor
Simulation of the formation, evaporation and transport of sulfuric acid clouds on
Venus using a general circulation model
Volcanism and Climate on Venus: An Updated Model
Taylor
Venus III book discussion
38
Tellmann
Tellmann
14
Titov / Markiewicz
The VeRa Radio Occultation Data Base: Atmosphere and Ionosphere
Waves in the Venus Atmosphere detected by the Venus Express Radio Science
Experiment VeRa
Venus cloud morphology: monitoring by the VMC/ Venus Express camera continued
Vandaele
Vandaele
Trace gases in the mesosphere and lower thermosphere of Venus from SOIR/VEX
Contribution of the SOIR/VEX instrument to VIRA II
26
Vasko
Fine structure of the Venus current sheet
8
Widemann
Mesospheric Temperature at Terminator using SDO/HMI Aureole Photometry,
DST/FIRS CO2 absorption spectroscopy and comparison with Venus Express
SPICAV-SOIR mesospheric aerosols observations and modelling
Svedhem
Wilquet
40
11
45
11
55
55
35
15
27
26
41
27
Yamamoto
Zalucha
Simulation of Venus’ polar vortex in the presence of diurnal thermal tide
Incorporation of a gravity wave momentum deposition parameterization into the
Venus thermosphere general circulation Model (VTGCM)
Zasova
Zasova
Thermal structure of the Venus mesosphere from remote sensing in the infrared
spectral range (VIRA II improvement)
The O2 nightglow from VIRTIS-M VEX measurements
20
Zhang
Physics of Induced Magnetosphere
5
INDEX ‐ PAGE IV 44
17
14
ORAL CONTRIBUTIONS
ORAL CONTRIBUTION Monday, 10 June Abstract Nr. 26
Venus: Earth’s (Neglected) Twin
Stofan, Ellen, Proxemy Research
Venus, so similar in size and composition to Earth, has a diverse and complex surface that has been
studied by spacecraft for over half a century, starting with the flyby of Mariner 2 in 1962. The Venera,
Vega, Pioneer Venus, Magellan, and now Venus Express missions have led to an increased
understanding of the surface and interior that lies under Venus’s clouds, and what this surface implies
about the planet’s evolution. From tesserae to coronae to volcanoes to mountain ranges and fracture
belts, analysis of the geologic features on the surface of Venus provide clues to its interior evolution.
The ~11 hotspot rises on Venus provide a window into interior processes, and indicate that the planet
is still active geologically. However, while our knowledge about Venus has greatly increased, the range
of theories to explain what we see remains quite large, and likley will remain so until future
investigations are conducted at the surface and in orbit around Venus. As we search beyond our own
solar system for Earth-like planets, it becomes more critical to understand why Earth’s twin is so
different and what it can tell us about Earth’s past and future.
Abstract Nr. 83
Search for active lava flows with VIRTIS on Venus Express
Mueller, Nils, Institute of Planetary Research, German Aerospace Center (DLR)
The VIRTIS instrument on Venus Express observes thermal emission from the surface of Venus at 1
µm wavelength and thus would detect sufficiently bright incandescent lava flows. No eruptions were
detected in the observations between April 2006 and October 2008. Models of the cooling of lava flows
on Earth are adapted to Venus ambient conditions to predict thermal emission based on effusion rate.
Taking into account the blurring of surface thermal emission by the atmosphere, the VIRTIS images
would detect eruptions with effusion rates above 500 to 1000 m3/s. Assuming the average eruption
volume and effusion rate distribution of Venus' lava flows is similar to that of the Hawaiian volcanoes
Mauna Loa and Kilauea, a typical VIRTIS observation would detect 4% to 10% of all lava flows within
its field of view and the whole data set is expected to lead to 0.02 detected eruptions per 1 km3 of
lava effused per year. Thus the VIRTIS data can constrain the rate of volcanism on Venus to be less
than about 100 km3/yr, at least a factor of 10 higher than existing constraints and the terrestrial value
of 4 km3/yr. While VIRTIS data does not place new constraints, the analysis shows that dedicated
volcano monitoring at Venus is feasible. There remains a large uncertainty because of the unknown
style of volcanism and the not well understood role of wind in lava surface cooling, but it could be
significantly reduced by analysis of high resolution radar images of flow fields and altimetry resolving
the thickness of flows.
Abstract Nr. 57
Venus surface geology from near infrared night side Venus Monitoring Camera images
Shalygin Eugene, Max-Planck Institute für Sonnensystemforschung; Basilevsky Alexander, Max-Planck
Institute für Sonnensystemforschung; Markiewicz Wojciech J., Max-Planck Institute für
Sonnensystemforschung; Titov Dmitrij, ESA-ESTEC
We analyse night-time near infra-red thermal emission images of the Venus surface obtained with the
1-µm channel of the VMC onboard Venus Express. We consider if SOME terrains have the different
emissivity (and thus mineralogic composition) in comparison to the surrounding basaltic plains.
Retrieved emissivity of tessera surface material is lower than that of relatively fresh supposedly
MONDAY, 10 JUNE ‐ PAGE 1 basaltic lavas of plains and volcanic edifices. This is consistent with the hypothesis that the tessera
material may be felsic. We found a possible decrease of the emissivity at the top of Tuulikki Mons
volcano which, if real, may be due to different (more felsic?) composition of volcanic products on the
volcano summit comparing to its slopes.
We simulated lava eruptions to access the possibility to detect ongoing volcanic activity. Simulations
showed that 1 square km lava flows should be marginally seen by VMC. 2-3 square km lava fields are
visible on the plains and 4-5 square km - even in deep rift zones.
Typical individual lava flows on Tuuliki Mons are large enough to produce contrasts of 1000% between
them and surroundings in VMC images. But typical lava flows from shield volcanoes on Earth often
have been being formed during weeks to months and the instantaneous size of the hot flow surface
was usually much smaller. Thus the detection probability is significantly lower, but it is far from being
negligible.
Abstract Nr. 120
Diverse Geologic Settings of Recent Volcanism on Venus and Implications for the Interior
Smrekar, Jet Propulsion Laboratory, NASA/Caltech
Analysis of VIRTIS data identified four primary areas of high 1-micron surface emissivity, interpreted
as evidence of recent volcanism. Prior analysis of gravity and topography of 3 of the 4 areas, as well
as interpretation of their surface geology, indicated that they are likely to be supported by a mantle
plume, or hotspots. New analysis of the gravity and topography of the Lada Terra shows that it is also
likely to be a hotspot. These features represent different geologic settings. Imdr and Dione are
similar to classical terrestrial style hotspot, will a broad topographic rise and 1-3 major volcanoes.
Themis Regio is a corona-dominated rise. It has a dozen volcanoes and a similar number of coronae,
which are thought to be manifestations of small-scale plumes. Many of the volcanoes and coronae
appear to have recent volcanism. This signature is interpreted as a plume coming from the core
mantle boundary that gets trapped at the upper-lower mantle boundary, giving rise to multiple smallscale thermal diapirs. Lada Terra is in a class of its own, with a broad topographic swell, with a
peripheral trough, rift system, and volcanism. The presence of active mantle plumes on Venus
indicates that there must be a thermal boundary layer at the core-mantle boundary, giving rise to
plumes. Taken together, these features provide a picture of the interior of Venus that includes a hot
thermal boundary layer at the core, a phase transition at the base of the upper mantle, a deformable
lithosphere, and a mantle that is heating up.
Abstract Nr. 47
Are terrestrial exoplanets Earth-like, Venus-like, or different ?
Christophe Sotin, Jet Propulsion Laboratory - Caltech
Since the discovery of the first exoplanet in the nineties, hundreds of candidates have been reported.
Among them, about a dozen are reported to have a density that compares with terrestrial planets,
which make them preferred targets for spectral determination of their atmospheres. Venus and Earth,
although very close in density, have evolved on very different pathways: different atmospheric
composition, lack of current plate tectonics on Venus, liquid water on the Earth’s surface. Venus
dynamics is in the so-called ‘stagnant lid regime’ whereas the Earth’s surface is fractured into several
plates which move relative to each other in relation with mantle convection. Parameters such as
surface temperature, size and atmospheric composition may influence the transition from one regime
to the other. Most of the exoplanets found so far may be closer to Venus characteristics than to Earth.
Searching for Earth-like planets where plate tectonics operates is a major endeavor in the field of
exoplanets. However, this study also suggests that some exoplanets may be remnant cores of giant
planets that migrated towards their star while losing their atmosphere by escape processes.
This work has been performed at the Jet Propulsion Laboratory, California Institute of Technology,
MONDAY, 10 JUNE ‐ PAGE 2 under contract to NASA. Government sponsorship acknowledged.
Abstract Nr. 82
The influence of rheology and volatiles on the geology of Venus
Ghail, Richard, Imperial College London
Pyroclastic activity is apparently almost absent on Venus, perhaps indicating a lack of volatiles in the
interior. However, an unusual feature near Diana Chasma likely originated as a pyroclastic surge
deposit. Its radar characteristics are only subtly different to those of the average Venus surface,
meaning that similar deposits may exist elsewhere but not be recognised and the interior may be
volatile-rich. Volatiles induce an asthenosphere, which together with decoupling of the crust and
mantle caused by the elevated surface temperature, enables stagnant lid recycling below the crust.
Fits to global hypsography imply a recycling rate of 5·0 ± 0·5 km² a⁻¹ and the loss of ~90% of a
scaled Earth-like heat production rate. Lid recycling by both plume activity and convection is
consistent with a number of features, particularly the global network of chasmata, by generating
major melting at upwelling sites, an adjacent region of minor melting aiding lateral slip, and
downwelling above geoid lows. An age of ~15 Ma is inferred for the western Eistla Regio plume and
subcrustal slip rates between 13 and 100 mm a⁻¹ are determined from fits to topographic profiles
across the principal chasmata. While Venus appears to be in thermal equilibrium now, higher rates of
radiogenic heat production in the past imply a greatly enhanced rate of magmatic resurfacing, which
1 Ga ago was capable of resurfacing the whole planet in ~40 Ma, implying a transition from an Io-like
volcanic planet to a tectonic dominated Earth-like regime over that time.
Abstract Nr. 05
Venus and Planetary Magnetism
Russell, Christopher T., UCLA; Cao, Hao, UCLA
A magnetic dynamo is a heat engine in which convection occurs in an electrically conducting medium.
As a planet cools rapidly, the transport of heat from the metallic core across the mantle to the surface
of the body does work by the production of a magnetic field. A source of heat from primordial thermal
energy (cooling of the core), radioactivity, latent heat release and expulsion of light fluids as a solid
inner core freezes all provide the necessary circulation and heat transport. In the case of a core in the
center of a planet, inefficient heat transport in the mantle and crust can stifle heat transport and shut
off a dynamo. This appears to have occurred on Venus. We review the physics of planetary dynamos
and Venus in particular. We also review the observational evidence on the current state of the Venus
dynamo.
Abstract Nr. 114
Large-scale magnetic flux ropes in low-altitude ionosphere of Venus: planetary origin or
solar wind origin
Luhmann, Janet G., UC Berkeley; Wei, Hanying, UCLA; Russell, Christopher T., UCLA; Zhang,
Tielong, Austrian Academy of Sciences
The Venus Express magnetometer observed large-scale magnetic structures of hundreds of kilometers
in spatial size near two hundred kilometer altitudes. Although occurring occasionally, these structures
strongly magnetize the low ionosphere (up to a hundred nano-tesla) and are quite different from the
small-scale magnetic flux ropes which are generated by the Venus-solar wind interaction with much
more frequent occurrence. Zhang et al. (2012) analyzed six such events in 2009 and suggest they
have different generation mechanism from the small-scale flux ropes, possibly crustal magnetic
remanent or magnetic reconnections. To understand the origin of these large-scale flux ropes, we
examine the 2009 data and find they occurs in about 10% of all orbits with locations very close to the
Venus geographic north pole (within 0.1 Venus radii). The correlation of occurrence with location and
MONDAY, 10 JUNE ‐ PAGE 3 the eastward component always being positive are consistent with the flux ropes having planetary
origin. However, the field component radial from the surface changes polarity from orbit to orbit and
does not agree with a crustal field picture. Moreover, the polarity and variation of the radial field are
controlled by the orientation of the draped solar wind magnetic field in the Venus magnetosheath,
suggesting the flux rope having solar wind origin. In this paper, we investigate these large-scale flux
ropes to understand their generation mechanism.
MONDAY, 10 JUNE ‐ PAGE 4 Tuesday, 11 June Abstract Nr. 49
Physics of Induced Magnetosphere
Tielong Zhang, Space Research Institute, Austrian Academy of Sciences, Graz, Austria
The term induced magnetosphere has been widely used by the recent Venus Express publications. For
a planet like Venus or Mars, which has no global intrinsic magnetic field but with atmosphere, an
induced magnetosphere is created by the solar wind interaction with the highly conducting ionosphere.
It consists of regions near the planet and its wake for which the magnetic pressure dominates all other
pressure contributions. The induced magnetosphere is therefore analogous to the magnetosphere of
an intrinsically magnetized planet, but occupies a smaller volume. In this talk, we review some of the
induced magnetosphere observations by Venus Express.
Abstract Nr. 08
Comparative Plasma Interactions and their Effects at Venus, Mars and Titan
Luhmann, J.G.; Wang, Y-C.;Ledvina, S.A., SSL, University of California, Berkeley; Ma, Yingjuan; Wei,
Hanying; Russell, C.T.,IGPP UCLA; Zhang, T-L., IWF, Graz; Barabash, S., IRF, Kiruna; Kallio, E.;
Jarvinen, R., FMI; Sillanpaa, I., SWRI; Westlake, J.,JHUAPL; Fang, X., LASP, University of Colorado
The 'weakly magnetized planets' Venus, Mars and Titan represent a sequence of increasingly complex
plasma interactions-with increasingly complex consequences. Venus is perhaps the best understood
because it is a case where the incident flow is supersonic and the relevant scalings allow fluid plus test
particle treatments of the system. The Mars case adds not only the complexity of the crustal magnetic
fields but also an increasing need to consider finite ion gyroradius effects. Titan presents some other
complications including the presence of a permanent external field component from the Saturn dipole
and subsonic interaction with a highly nonthermal external particle population. And Titan's atmosphere
is also greatly extended compared to its planetary counderparts. We take a look at what we have
learned about some of the similarities and contrasts, and consider still open issues of interest for
future investigations and comparative studies.
Abstract Nr. 108
How the near-Venus space affects the planet
Stas Barabash, Swedish Institute of Space Physics
The solar wind flowing around Venus affects the planet’s atmosphere and ionosphere via energy,
matter, and momentum transfer. The energy transfer causes the non-thermal escape of planetary
ions. The matter transfer results in the deposition of the solar wind hydrogen and helium into the
atmosphere. The momentum transfer causes atmospheric sputtering. There might even occur
processes involving the angular momentum transfer to the upper ionosphere. We review the most
recent observations of all these processes by the ASPERA-4 instrument onboard Venus Express
(Analyzer of Space Plasmas and Energetic Atoms) and compare them with two other terrestrial
planets, Mars and Earth. The overall conclusion is at the present time the induced magnetosphere of
Venus creates a strong magnetic barrier substantially reducing the influence of the near-Venus
environment on the planet.
Abstract Nr. 95
Ion escape from Venus
TUESDAY, 11 JUNE – PAGE 5 Stenberg Gabriella, Swedish institute of space physics; Barabash Stas, Swedish institute of space
physics; Futaana Yoshifumi,Swedish institute of space physics
We use more than three years of data from the ASPERA-4 instrument onboard Venus Express to
estimate the net outflow of protons and heavy ions from Venus.
The ion escape appears to exclusively take place in the induced magnetotail region and no heavy ions
are present in the magnetosheath. Protons of solar wind origin are travelling around the planet and
penetrating the tail, resulting in a mix of planetary and solar wind protons inside the induced
magnetosphere boundary. The escape rates of ions inside the tail agree with results from recent
published studies, where other analysis methods have been used.
We also present average flux patterns in the near Venus space based on computed average
distribution functions.
We compare our results for Venus with a recent study of ion escape from Mars, where the same
analysis method has been applied to data from the ASPERA-3 instrument on Mars Express.
Abstract Nr. 70
Dependence of O+ escape rate from the Venusian upper atmosphere on IMF directions:
ASPERA-4 observations
Masunaga Kei, Swedish Institute of Space Physics, Kiruna, Sweden; Futaana Yoshifumi, Swedish
Institute of Space Physics, Kiruna, Sweden; Stenberg Gabriella, Swedish Institute of Space Physics,
Kiruna, Sweden; Barabash Stas, Swedish Institute of Space Physics, Kiruna, Sweden; Zhang
Tielong, Space Research Institute, Austrian Academy of Science, Graz, Austria; Fedorov
Andrei, Centre d’Etude Spatiale des Rayonnements, Toulouse, France; Okano Shoichi, Institute for
Astronomy, University of Hawaii, Pukalani, HI, USA; Terada Naoki, Department of Geophysics,
Graduate School of Science, Tohoku University, Sendai, Japan
We present the dependence of O+ escape flux rate on the upstream interplanetary magnetic field
(IMF) direction calculated from the data obtained from the Analyser of Space Plasma and Energetic
Atoms (ASPERA-4) instrument and the magnetometer (MAG) onboard Venus Express. The data in the
period between June 21, 2006 and May 31, 2010 is classified into two cases: the perpendicular IMF
case (167 events) and the parallel IMF case (82 events), where IMF is nearly perpendicular to the
solar wind velocity and nearly parallel to it. We average O+ fluxes observed in the nightside region and
statistically calculate the escape rate for each IMF case. The O+ escape rates of (5.8 ± 2.9) × 1024 s1
(perpendicular IMF case) and (4.9 ± 2.2) × 1024 s-1 (parallel IMF case) are obtained. Since these
values are not significantly different, we conclude that several acceleration mechanisms must balance
each other in order to keep the escape rate constant.
Abstract Nr. 109bis
Comparisons of Venus Express measurements with an MHD model of O+ ion flows:
Implications for atmosphere escape measurements
McEnulty, Tess, LASP, University of Colorado, Boulder; Yingjuan Ma, IGPP, University of California, Los
Angeles; Janet G. Luhmann, SSL, University of California, Berkeley; Demet Ulusen, Space
Technologies Research Institute, Ankara, Turkey; Imke de Pater, Department of Astronomy, University
of California, Berkeley; Andrei Fedorov, Institut de Recherche en Astrophysique et Planetologie,
Toulouse, France; David Brain, LASP, University of Colorado, Boulder
The Venus Express (VEX) Ion Mass Analyzer (IMA) detects low energy (< 100 eV) oxygen ions flowing
into the wake. Investigators have suggested that the majority of the O+ escape measured by the IMA
is in this low energy population. However, the spacecraft potential and relative velocity complicate
interpretation of these ions. Due to these complications, there is still an open question of whether or
not all of these low energy ions are actually escaping. Some of the measured ions may actually be
gravitationally bound, even out to ~1.5 Venus radii in the wake. To illustrate these complications in
interpreting these measured low energy ions, we compare VEX ion measurements in this region to
results from a magnetohydrodynamic model. The model simulations highlight how IMA measurements
TUESDAY, 11 JUNE – PAGE 6 +
of O can be affected by the spacecraft relative velocity and potential. In addition, we simulate
multiple different orbit trajectories in the model and show how the O+ IMA measurements depends on
orbit geometry and interplanetary magnetic field direction. We then integrate O+ escape flux in the
wake region of the model along the VEX orbit to illustrate how non-escaping (gravitationally bound)
ions could affect estimates of total O+ escape.
Abstract Nr. 101
Solar Wind energy and momentum transfer - Effects on the Venus polar thermosphere
Lundin Rickard, Swedish Institute of Space Physics; Barabash, S., Swedish Institute of Space Physics;
Futaana, S., Swedish Institute of Space Physics; Holmstrom, M., Swedish Institute of Space Physics;
Perez-de-Tejada. H., UNAM, Mexico City, Mexico; Sauvaud, J-A., CESR/CNRS Toulouse, France
An analysis of the average ion flow properties in the Venus magnetosphere and plasma tail reveals the
existence of a large-scale flow vortex, i.e. solar wind H+ (SW H+) and ionospheric O+ curling righthanded tailward (as viewed from the Sun. The vortex commences at dusk (-Y), driven by a transverse
(to the solar wind) aberration flow component. Dusk magnetosheath and ionospheric ions move
westward across the nightside into the dawn sector, from where the tailward and lateral flow merges
into a tailward-moving vortex. Analyzing the fluid dynamics of the SW H+ energy and momentum
(E&M) transfer to O+ at the terminator, we find that E&M balance (efficiency ≈1) is achieved in the
altitude range 1200 - 600 km. Below 600 km a combined Westward O+ and energetic neutral atom
(ENA) flow completely dominates the momentum flux, the average O+ and ENA flow going in the
direction of the Venus atmospheric superrotation.
An analysis of the solar wind H+ ionospheric O+ energy and momentum (E&M) transfer to the neutral
gas in the Venus thermosphere and upper atmosphere over the polar region, reveals that
external/solar wind, and the corresponding ionospheric ion forcing, may drastically affect the short
term wind pattern down to 150 km. For instance, we find that the average ionospheric O+ wind is
capable, via ion drag, to set a polar cap CO2 air mass at 150-200 km altitude in motion by 200 m/s in
less than 5 minutes. Below 150 km, E&M transfer downward to the upper atmosphere is expected due
to frictional forcing, although at a much slower pace.
Abstract Nr. 107
The plasma vortex in the Venusian plasma tail. Steady-state reconnection or fluid motion?
Fedorov Andrey, IRAP/UPS/CNRS, Toulouse, France; S. Barabash, IRF, Kiruna, Sweden; T.L.
Zhang, University of science and technology, Hefei, China; J.A. Sauvaud, IRAP/UPS/CNRS, Toulouse,
France
The plasma and magnetic field statistics, accumulated since 2006 by Venus Express Aspera-4 and
MAG data show:
1. The minimum of the magnetic fileld in the close Venusian wake
2. The planetward averaged ion flow observed in the same region.
The case study (Zhang, 2012, Nature) gives at least one evidence of the plasmoid-like event that can
be associated with a tail magnetic reconnection.
The present paper combines statistical and case studies to answer the question: if the observed
plasma vortex is caused by a pseudo-steady state reconnection, or it is a characteristic fluid motion.
Abstract Nr. 74
Cosmic ray ionization in the Venusian atmosphere from Monte Carlo modelling
Tom Nordheim, Mullard Space Science Laboratory, University College London; Lewis R. Dartnell, UCL
Institute for Origins, University College London; Andrew J. Coates, Mullard Space Science Laboratory,
University College London
The atmospheres of the terrestrial planets are constantly exposed to solar and galactic cosmic rays,
TUESDAY, 11 JUNE – PAGE 7 the most energetic of which are capable of affecting deep atmospheric layers through nuclear and
electromagnetic particle cascades. The energy deposited by these interactions is thought to be an
important driver for atmospheric chemistry and may possibly affect cloud microphysics, and in regions
beneath the penetration of ultraviolet radiation, cosmic rays are the primary ionization agent. It is
therefore crucial to quantify the amount of energy deposited by cosmic rays in the atmosphere by
altitude, as this is required to estimate ionization and conductivity profiles.
Detailed studies have considered the propogation of cosmic rays in the atmospheres of Earth, Mars,
Titan and the Giant Planets. However, to date, only a few studies (Dubach et al, 1974; Borucki et al,
1982) have considered such interactions in the Venusian atmosphere, notably using Boltzmann
transport approximations. In this work we will present preliminary results of full Monte Carlo modelling
of solar and galactic ray cosmic ray primaries interacting with the Venusian atmosphere during solar
minimum and maximum conditions. In addition, the radiation dose during extreme events (e.g
Carrington Flare event) will be discussed.
Abstract Nr. 02
Ionospheric magnetic fields and currents at Mars and Venus
Dubinin E., Max-Planck-Institute for Solar System Research, Lindau, Germany
Mars Express and Venus Express spacecraft have provided us a wealth of in-situ observations of
characteristics of induced magnetospheres of Mars and Venus at low altitudes during solar minimum
conditions. At such conditions large-scale magnetic fields are observed deeply in the ionospheres
(magnetized ionospheres). The observations again raise a long-standing question about the origin of
these fields. The problem is intimately related to the issue of electric current system and their closure.
Analysis of ASPERA-3, ASPERA-4, MARSIS and MAG data reveals a lot of features which require a
more sophisticated view at the origin and the topology of the ionospheric magnetic fields. Differing
perspectives at this problem are widely discussed.
Abstract Nr. 122
Fine structure of the Venus current sheet
Vasko Ivan, Space Research Institute, Moscow; Zelenyi Lev, Space Research Institute, Moscow;
Artemyev Anton, Space Research Institute, Moscow; Petrukovich Anatolii, Space Research Institute,
Moscow; Zhang Tielong, IWF, Graz; Fedorov Andrei, CNRS, France; Malova Helmi, Space Research
Institute, Moscow; Popov Viktor, Space Research Institute, Moscow; Nakamura Rumi, IWF, Graz
One of the gaps in our knowledge of the Venus current sheet (CS) is the CS thickness. The reason is
that the CS is in motion during observations (flapping motion) and the velocity of the flapping motion
cannot be determined by the single-spacecraft mission. On the other hand one can say something
about the CS spatial scale by studying the fine structure of magnetic field profiles. We have used the
data of Venus Express mission to study the structure of the Venus CS near the planet based on the
statistics of 13 CS crossings observed during steady conditions in the solar wind in years 2006-2010.
We have found that observed magnetic field profiles can be separated into single-scale and doublescale. Plasma data have shown that double-scale CSs are oxygen-dominated, while single-scale CSs
can be proton-dominated as well as oxygen dominated. The observed profiles can be adequately
described in the frame of thin anisotropic CS model. The model predicts that double-scale CSs appear
due to the trapped oxygen population, picked up from the ionosphere. In addition the model predicts
that the CS thickness is only several particle gyroradii.
Abstract Nr. 93
Ionospheric photoelectron observations at Venus
Coates Andrew, UCL-MSSL; Wellbrock Anne, UCL-MSSL; Frahm Rudy, SwRI; Winningham
David, SwRI; Barabash Stas, IRF; Lundin R, IRF
TUESDAY, 11 JUNE – PAGE 8 The Venus ionosphere at the top of the planet’s thick atmosphere is sustained by photoionization. The
consequent photoelectrons may be identified by specific features in the energy spectrum at 20-30 eV.
The ASPERA-4 electron spectrometer has an energy resolution designed to identify the photoelectron
peaks. Photoelectrons are seen not only in their production region, the sunlit ionosphere, but also at
more distant locations in the Venus environment. Here, we present a summary of the work to date on
observations of photoelectrons at Venus, and their comparison with similar processes at Titan and
Mars, and we present further data on the distant photoelectrons at Venus.
Abstract Nr. 86
A survey of Hot Flow Anomalies at Venus
G.A. Collinson, Heliophysics Science Division, NASA Goddard Space Flight Center, USA; D.G.
Sibeck, Heliophysics Science Division, NASA Goddard Space Flight Center, USA; A. Masters, Institute
of Space and Astronomical Science, JAXA, Japan; N. Shane,Mullard Space Science Laboratory,
University College London, UK; T.L. Zhang, Austrian Academy of Sciences, Space Research Institute,
Gratz, Austria; A. Fedorov, Universite de Toulouse, UPS-OMP, IRAP, Toulouse, France; S.
Barabash, Swedish Institute of Space Physics, Kiruna, Sweden; A.J. Coates, Mullard Space Science
Laboratory, University College London, UK; T.E. Moore,Mullard Space Science Laboratory, University
College London, UK; J.A. Slavin, University of Michigan, Ann Arbor, Michigan, USA
We present the first survey of Hot Flow Anomalies (HFAs) at the bow shock of Venus, expanding on
our recent initial case study of a single event [Collinson et al., 2012]. HFAs are an explosive plasma
phenomena, through the interaction between an interplanetary current sheet and a planetary bow
shock, wherein a pocket of reflected solar wind plasma becomes heated and rapidly expands. We
show that the newly discovered Cytherean HFAs are very important at Venus because: (1) they are
common, occurring at a rate of ~2 per day; (2) They are very large when compared to the overall size
of the system (0.4-1.7 Rv or (~130% of the sub-solar bow shock distance); and (3) unlike at
magnetized planets, occur very close (1.5-3Rv) to the surface of the planet. Given that the large
fluctuations in pressure associated with an HFA drive large motions in the location of the Earth’s
magnetopause, HFAs have the potential to be extremely disruptive to the induced magnetosphere and
unprotected ionosphere of Venus. Thus we hypothesize that HFAs have a much more dominant role in
the dynamics of the induced magnetosphere of Venus relative to the magnetospheres of magnetized
planets.
Abstract Nr. 09
The Implications of the Observed Evolution of the Co-Orbiting Material in 2201 Oljato’s
Orbit Observed by PVO and VEX
Russell, Christopher T., UCLA; Lai, Hairong, UCLA; Delzanno, Gian Luca, LANL; Zhang,
Tielong, Austrian Academy of Sciences
The observation with PVO and VEX of the time-varying IFE rate in the “Oljato-sensitive” sector of
ecliptic longitudes provides an important window into how “meteor” streams evolve. The fact that
there was a broad region of increased IFE occurrence centered around Oljato suggests that material
was broken free from Oljato sometime before 1980. These newly produced “bolides” themselves
evolved over a period of about 20 years so that they were no longer producing collisions in 2012. This
suggests that a warning system for Earth could be developed by launching a set of perhaps a dozen
small magnetometer-equipped spacecraft that would have a 1-year orbit period, but would orbit the
Sun in a slightly elliptical orbit so the satellites would spend time inside and outside 1 AU, but remain
ahead of the Earth in its orbit a fixed offset to provide time for analysis and follow-up. When swarms
of IFEs are seen at longitudes of known near-1-AU crossing objects, radar and optical measurements
could be made along that body’s orbit when the Earth reached that longitude. When hazardous coorbiting material was located, a decision could be made as to whether it was necessary to destroy or
remove it and how to accomplish this. We note that we already have spacecraft at 1 AU around Earth
and displaced from Earth (STEREO A and B). These spacecraft could be used to test this concept
before deployment.
TUESDAY, 11 JUNE – PAGE 9 Wednesday, 12 June Abstract Nr. 51
Venus GCM modelling: current status and perspectives in the light of Venus Express
datasets
Lebonnois Sebastien, LMD, CNRS
In recent years, the study of Venus atmospheric system has made a step forward, thanks to the
combination of new observations from Venus Express and of development of evolved General
Circulation Models (GCM).
During this talk, I will review the available GCMs developed around the world and their most recent
results. The difficulties met when comparing them with each other, potentially related to the tricky
question
of
angular
momentum
conservation
in
these
tools,
will
be
mentioned.
These models benefit from the recent Venus Express datasets: temperatures in the cloud region and
above (VIRTIS, VeRa, SPICAV), cloud-tracking wind speeds (VIRTIS, VMC), composition below and
above the clouds (VIRTIS, SPICAV), as well as their time variability where wave activity is now put to
evidence. The role of the thermal tides in the dynamics and their observations will be discussed.
Among these GCMs, I will present in more details the perspectives for the LMD GCM, developed in
close collaboration with colleagues from LATMOS. Recently, we have used idealized tracers to study
how the circulation may explain the latitudinal profiles of CO and OCS around 35km of altitude (E.
Marcq, LATMOS). The implementation of a photochemical module is underway (F. Lefèvre and A.
Stolzenbach, LATMOS), and a microphysical model for clouds is also in development (A. Määttänen,
LATMOS). At LMD, we are studying the impact of adding a parametrization for gravity waves
generated close to the surface, and prepare new parameterizations to extend the model top up to 140
km.
Abstract Nr. 109
Non-hydrostatic general circulation model of the Venus atmosphere
Rodin Alexander, Moscow Institute of Physics and Technology, Space Research Institute; Mingalev
Igor, Polar Geophysical Institute; Orlov Konstantin, Polar Geophysical Institute
We present the results of general circulation simulations of the Venus atmosphere based on full set of
gas dynamics equations. There are several regions in the Venus atmosphere where breaking
hydrostatic balance may influence general circulation, including polar vortices. The model implements
the explicit semi-Lagrangian integration technique and allows for transport of passive tracers. Thermal
forcing could be simulated optionally either by relaxation to specified temperature field, or by fullscale radiative transfer solver based on consecutive scattering order approximation. The model takes
advantage of GPU accelerators using CUDA technology and runs on spatial grids with the resolution
1.4o in horizontal scale and 250 m in the vertical.
Simulations reproduce the vertical and latitudinal structure of zonal superrotation, typically splitting
into two midlatitude jets. Above 100 km the model reveals complex flow patterns that may be
interpreted as a manifestation of the subsolar-antisolar circulation. Simulations also reproduce polar
vortices with variable zonal wavenumber, characterized by strong downwelling motion in the central
area. The maintenance of vortices suggest extra cooling of the circumpolar atmosphere within the
cloud deck and heating above the clouds.
The work has been supported by the Ministry of Education and Science of
Russian Federation grant #11.G34.31.0074 and Russian Academy of
WEDNESDAY, 12 JUNE – PAGE 10 Sciences program #22
Abstract Nr. 10
Structures and generation mechanisms of the Venus atmospheric superrotation
Takagi, Masahiro, Kyoto Sangyo University; Matsuda, Yoshihisa, Tokyo Gakugei University
The Venus atmospheric superrotation is one of the most remarkable phenomena in the planetary
science. Though several mechanisms have been proposed so far, the generation mechanism remains
unclear.
In the present study, we focus on the Gierasch mechanism (GM) and the thermal tide mechanism
(TTM). In order to examine their dynamical interactions, some numerical experiments with different
distributions of the solar heating have been carried out. The results show that the superrotation is
maintained by GM and TTM, independently. The spatial structures of the mean zonal flow are different
for these cases. The midlatitude jets are formed only in the GM case. It is also noted that GM can
work with the realistic solar heating, unlike the previous studies (Yamamoto and Takahashi 2003;
Hollingsworth et al. 2007). The difference may be due to the initial condition, which is the
superrotating flow in the present study. In the case with the diurnal heating (i.e., both GM and TTM
are included), the superrotation is maintained by TTM mainly, because the mean meridional circulation
is localized in the upper atmosphere above the cloud layer. It is also found that several kinds of waves
including the baroclinic instability waves appear. These waves which are excited in the low static
stability levels may contribute to the momentum and heat transport.
Abstract Nr. 06
Baroclinic modes in the Venus atmosphere simulated by AFES (Atmospheric GCM For the
Earth Simulator)
Sugimoto Norihiko, Keio University; Takagi Masahiro, Kyoto Sangyo University; Matsuda
Yoshihisa, Tokyo Gakugei University
An atmospheric general circulation model (AGCM) for Venus is being developed on the basis of AFES
(AGCM For the Earth Simulator) in order to study phenomena on Venus atmosphere by the numerical
simulation with high resolution. As a first step toward long time high resolution numerical simulation
to reproduce super-rotation, we investigate unstable modes on the condition of the idealized superrotation by T42L60 numerical simulation with realistic static stability. Super-rotation is assumed to
exist at initial state and to be maintained by the relaxation forcing due to the meridional temperature
gradient. In the time evolution of this setting, baroclinic modes grow in the cloud layer with small
static stability. The structures of unstable modes are similar to those obtained in the previous linear
stability analysis initially, but changed by the nonlinear interactions in the later stage. Meridional
transport of momentum and heat by these unstable modes is discussed. The results of T159L120 high
resolution simulation, long time (300 years) numerical simulations with and without solar heating,
starting from state of rest and super-rotation, will be shown in the presentation.
Abstract Nr. 46
Global Vortex Circulation on Venus - an assessment from Venus Express Observations
Limaye, Sanjay, University of Wisconsin; Markiewicz, Wojciech, Max Planck Institute for Solar System
Research
Seven years of observations of Venus Express provide an idea of the range of the basic cloud level
zonal circulation of the atmosphere and the accompanying global cloud morphology and some
information about the circulation above and below the clouds. The results of these observations and
the recent efforts in numerical simulations of the global circulation point to gaps in our knowledge
WEDNESDAY, 12 JUNE – PAGE 11 needed to understand the maintenance of the superrotation of the atmosphere. VMC and VIRTIS
observations provide information about the top of clouds and middle cloud level on Venus while the
VeRa thermal structure profiles constrain the thermal support for the circulation between about 45 -85
km above the mean surface. Inferences about the circulation above 85 km come from airglow
observations from VIRTIS and from the SOIR and SPICAV thermal structure profiles. Of these, VMC
provides the most continuous record of the southern hemisphere. These observations show recurring
dynamical features in the core region of the vortex while away from the core region considerable
asymmetry is seen many times.
The relative stability and longevity of global vortex circulation which was first inferred from 1974
Mariner 10 observations and indicated by Pioneer Venus Orbiter (1978 – 1983) and Galileo fly-by
(1990) through the Venus Express epoch suggest that the vortex has been a long term feature of the
atmosphere for a very long time. In fact, as there is little evidence for the supply of the energy, it is
likely that the vortex circulation on Venus is the longest lived vortex and the largest in terms of
relative size compareed to the planet.
We still lack definitive measurements that can provide the meridional transport of angular momentum
at any level as a function of latitude with confidence to assess the relative importance of the proposed
mechanisms for the maintenance of the superrotation.
Abstract Nr. 34
Measurements of Venus winds from ultraviolet, visible and near infrared images with
VIRTIS on Venus Express
Hueso, Ricardo, Dpto. Física Aplicada I, Escuela Técnica Superior de Ingeniería, UPV/EHU, Bilbao
(Spain); Bandos, Tatyana, Dpto. Máquinas y Motores Térmicos, Escuela Técnica Superior de
Ingeniería, Universidad del País Vasco, UPV/EHU, Bilbao (Spain); Garate-Lopez, Itziar, Dpto. Física
Aplicada I, Escuela Técnica Superior de Ingeniería, UPV/EHU, Bilbao (Spain); Peralta, Javier,Instituto
de Astrofísica de Andalucía, (CSIC) Granada (Spain); Sánchez-Lavega, Agustín, Dpto. Física Aplicada
I, Escuela Técnica Superior de Ingeniería, UPV/EHU, Bilbao (Spain)
After 6 years orbiting Venus the Venus Express mission has provided the largest database of visual
and infrared observations of the Venus clouds at different layers with the combination of VMC and
VIRTIS instruments. We present further measurements of cloud motions in the South hemisphere of
Venus obtained from the VIRTIS-M visible channel observations at different wavelengths sensitive to
the upper cloud haze at 65-70 km height (dayside ultraviolet images) and the middle cloud deck
(dayside visible wavelengths and near infrared images around 1 mm) about 5 km deeper in the
atmosphere. The measurements were obtained with a semi-automatic cloud correlation algorithm that
largely avoids spurious measurements and is robust enough to be used in images of very different
characteristics in terms of signal to noise ratio, spatial resolution and time separation between
images. We focus this study on wind measurements of the South Polar latitudes closing around the
South Polar Vortex and on the middle cloud deck whose motions and variability have not been studied
in detail before because of low contrast of atmospheric features in these wavelengths. We use a
combination of VIRTIS images in nearby wavelengths to increase the signal to noise ratio and apply
strong image spatial filters to increase the contrast of the atmospheric details. Both cloud layers are
studied simultaneously to infer similarities and differences between vertical levels, cloud morphologies
and winds. We summarize the result of the new measurements and compare with our previous studies
of winds with VIRTIS data.
Abstract Nr. 20
Atmospheric Oscillation in the atmosphere of Venus: the Cupido effect
Bertaux Jean-Loup, LATMOS/UVSQ/CNRS
As observed by SPICAV on Venus Express, the quantity of SO2 above the clouds of Venus has
drastically changed in the recent years (Marcq et al., 2012), reaching a maximum around 2007,
WEDNESDAY, 12 JUNE – PAGE 12 followed by a strong decrease (factor 5-10). Assuming that this is not due to volcanic activity, it
reveals a major change in the atmospheric circulation pattern, since SO2 is a tracer of upwelling. A
similar decrease was observed after 1978 by Pioneer Venus. This suggests that SO2 variations are a
sign of a global atmospheric oscillation, periodic or pseudo-periodic, reminiscent of Earth Quasi
Biennial Oscillation (QBO), or El Niño-La Niña phenomenon. By analogy, we propose to name this new
Venus oscillation “the Cupido effect”, after the name of the son of Venus. We will discuss the possible
relation of the Cupido effect with three topics. One Venus general circulation model produces decadal
variations (Parish et al., 2011) that could be essentially the Cupido effect. The zonal wind speed at
Venus cloud top is observed (with VMC) to increase since 2006 (Khatuntsev et al., 2012). The rotation
of the solid body as measured accurately by Magellan radar in 1990-1992 at 243. 0185 ± 0.0001 days
is significantly faster than the rotation averaged over 16 years at 243.023±0.002 days as measured
by VIRTIS with thermal IR features on the ground of Venus (Mueller et al., 2012). Such a change of
the rotation period could be associated to atmospheric changes, as is observed on Earth.
Abstract Nr. 45
Variations of the radiative forcing induced by the cloud top structure changes of the Venus
mesosphere
Lee, Y.J., ISAS/JAXA, Japan; Titov, D., ESA/ESTEC, the Netherlands; Ignatiev, N., IKI, Russia;
Tellmann, S., Rheinish Institute for Environmental Research, Germany; Pätzold, M., Rheinish Institute
for Environmental Research, Germany; Piccioni, G., INAF-IAPS, Italy
The radiative forcing by the clouds is one of important parameters to understand the radiative energy
balance of the Venus mesosphere. The thick clouds (48-70 km) reflect ~76 % of solar radiation back
to space. About 70 % of remaining solar flux is absorbed above 60 km altitude by clouds, gases, and
unknown UV absorber [Crisp 1986; Crisp and Titov, 1997]. Also, the clouds absorb a large fraction of
the outgoing thermal emission from the hot deep atmosphere, making them the second strongest
greenhouse agent in the Venus atmosphere [Bullock, 1997]. Then, temperature and cloud top
structure determine the outgoing thermal emissions.
Venus Express observations revealed significant changes in the cloud top altitude and aerosol scale
height [Ignatiev et al., 2009; Lee et al., 2012]. We performed full radiative transfer modeling of the
solar and thermal radiation with cloud top structure variations and latitudinal temperature. The
sensitivity study shows the solar heating rate at the cloud top level changes from 10 K/day to 95
K/day in the sub-solar region depending on the cloud top structures. We found that around one-third
of total solar heating at the cloud tops was the contribution of the unknown UV absorber, in the
averaged low latitude condition. The sensitivity study of the thermal cooling rate shows the 5-30
K/day range of variations depending on the cloud top structures. Diurnal averaged net radiative
forcing shows an increasing net cooling at the cloud tops from -0.1~-2.5 K/day at low latitudes to -11
K/day in the polar region.
Abstract Nr. 61
Thermal Structure of Venus Mesosphere as Observed by VIRTIS - Venus Express
Grassi Davide, IAPS-INAF; Migliorini Alessandra, IAPS-INAF; Politi Romolo, IAPS-INAF; Ignatiev
Nikolay, IKI-RAS; Piccioni Giuseppe, IAPS-INAF; Drossart Pierre, Observatoire de Paris - Meudon
We review here the results achieved by VIRTIS in studying the air
temperature fields of Venus mesosphere (65-90km). Measurements are
limited to nighttime conditions, since during daytime the 4.3 microns band is
prone to non-LTE contamination.
Main features of temperature fields.The 'cold-collar' previously detected by
Pioneer Venus Orbiter is the most striking structure in Venus temperature
fields. It is observed in both hemispheres and is centered about 70 degrees
from the equator; it extends vertically up to 70 km above the mean surface.
WEDNESDAY, 12 JUNE – PAGE 13 Similarly, the 'polar dipole' is also detected in temperature fields, where its
signature is confined below 70 km.
Latitude/local time average temperature fields.VIRTISdataset size allows
to bin temperature retrievals according different parameters. For their
implication on dynamical phenomena occurring in the Venus atmosphere,
average air temperature fields in the local time/latitude/pressure space are
of special interest. VIRTIS-M maps show the occurrence of a temperature
minima in the cold collar around 2-3 LT, while at higher levels (80 km) the
morning side is warmer than its evening counterpart. Despite the sparsity of
sampling, these features are also suggested by VIRTIS-H observations in the
northern hemisphere.
Latitude/longitude average temperature fields. Time series analysis of
VIRTIS-M retrieved temperatures indicate a clear periodicity equal to one
Venus solar day. This observation lead to an investigation of average
latitude/longitude/pressure air temperature fields from VIRTIS-M data. The
expected longitudinal uniformity is violated by a particularly cold collar
between 180E and 270E and a warm region at 120E, 70S at the 12.6 mbar
level (75 km).
Abstract Nr. 124
Thermal structure of the Venus mesosphere from remote sensing in the infrared spectral
range (VIRA II improvement)
Zasova Ludmila, (1) IKI RAS, Moscow, (2) MIPT, Dolgoprudny, Russia; Gorinov Dmitry, (1) IKI RAS,
Moscow, (2) MIPT, Dolgoprudny, Russia; Grassi Davide, (3) IASP-INAF, Rome, Italy; Migliorini
Alessandra, (3) IASP-INAF, Rome, Italy; Haus Rainer, (4)DLR, Berlin, Germany; Piccioni Giuseppe, (3)
IASP-INAF, Rome, Italy; Pierre Drossart, (5) LESIA, Paris, France
We analyze the measurements of two spectrometers: VIRTIS –M on Venus Express and Fourier
spectrometer on Venera-15 (FSV15). Both experiments worked on polar orbits. The first one made
measurements in 2006 – 2009 and obtained millions spectra in the near IR spectral range. From
VIRTIS-M data the temperature profiles were retrieved from 4.3 µm CO2 band on the night side only.
It was covered altitude range from 65 to 95 -100km, latitudes 20 -80 °S ( Grassi, Migliorini). FSV15
worked for 2 month in 1983 and it was obtained about 1500 spectra in the thermal IR. Temperature
profiles were retrieved from 15 μm CO2 band. At each orbit the measurements were made practically
simultaneously (within 1 hour) on the day and night sides symmetrically for latitudes from 20 to 87 N.
Coverage in local time was not perfect, observations around noon and around night are absent. In
spite of this, four amplitudes of thermal tide vs. latitude and altitude were calculated (Zasova et al.
2007). After comparison of the VIRTIS averaged data and FSV15 it was found many similarities
(Grassi et al. 2010). The aim of this work is more detailed comparison of the retrieved thermal
structure of the mesosphere from VIRTIS and FSV15. It was studied also temporal variation using
brightness temperature (it approximately corresponds to temperature in atmosphere at H(τ =1) from
VIRTIS data. It was averaged data over several periods of observations and compare the T(φ, LT) at
different altitude levels. It was found significant temporal variation, especially in the upper
mesosphere.
Abstract Nr. 66
The VeRa Radio Occultation Data Base: Atmosphere and Ionosphere
Tellmann, Silvia, Rheinisches Institut fuer Umweltforschung (RIU), Department of Planetary Research,
Cologne, Germany; Haeusler, Bernd, Institut für Raumfahrttechnik, Universitaet der Bundeswehr
WEDNESDAY, 12 JUNE – PAGE 14 Muenchen, Munich, Germany; Paetzold, Martin,Rheinisches Institut fuer Umweltforschung (RIU),
Department of Planetary Research, Cologne, Germany; Bird, Michael K.,Argelander-Institut fuer
Astronomie, University of Bonn, Bonn, Germany; Imamura, Takeshi, Institute of Space and
Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa, Japan; Hinson,
David P. , Department of Electrical Engineering, Stanford University, Stanford, California, USA; Tyler,
G. Leonard, Department of Electrical Engineering, Stanford University, Stanford, California, USA;
Withers, Paul, Space Science Section, Boston University, Boston, MA, USA; Peter, Kerstin, Rheinisches
Institut fuer Umweltforschung (RIU), Department of Planetary Research, Cologne, Germany;
Oschlisniok, Janusz, Rheinisches Institut fuer Umweltforschung (RIU), Department of Planetary
Research, Cologne, Germany
The Venus Express Radio Science Experiment VeRa performs routinely radio-sounding measurements
of the Venus atmosphere and ionosphere as part of the ESA Venus Express (VEX) mission since 2006.
A total of more than 700 vertical scans of the Venus ionosphere and atmosphere were obtained until
the end of February 2013.
The polar orbit of VEX provides the opportunity to study the troposphere and mesosphere between 40
– 90 km at almost all planetocentric latitudes under varying illumination conditions.
The temperature profiles are investigated with regard to latitudinal and local time dependencies.
Comparisons will be shown with the VIRA model of the lower atmosphere. The Mesosphere shows a
high variability resulting from atmospheric waves and turbulence.
The ionosphere consists of a two layer structure between 115 km to 160 km. The main layer V2 is
dominantly formed by solar EUV photoionisation, the lower V1 is formed by solar X-ray and dominant
secondary ionization.
The ionospheric data set covers a period of changing solar activity. The topside is highly variable and
the ionopause is located at extremely low altitudes (250 – 330 km) during the declining phase of the
solar cycle and at solar minimum .
These data are compared with the VIRA ionospheric data which are based on Pioneer Venus
occultations observed during solar minimum. The modeling of observed electron density profiles
based on the VIRA neutral background atmosphere shows a general agreement with the V2 peak
densities but a systematic underestimate of the V2 peak altitude for low solar zenith angles. The
modeled V2 layer width is systematically too broad.
Abstract Nr. 68
Waves in the Venus Atmosphere detected by the Venus Express Radio Science Experiment
VeRa
Tellmann, Silvia, Rheinisches Institut fuer Umweltforschung (RIU), Department of Planetary Research,
Cologne, Germany; Haeusler, Bernd, Institut für Raumfahrttechnik, Universitaet der Bundeswehr
Muenchen, Munich, Germany; Hinson, David P.,Department of Electrical Engineering, Stanford
University, Stanford, California, USA; Tyler, G. Leonard, Department of Electrical Engineering,
Stanford University, Stanford, California, USA; Andert, Thomas P., Institut für Raumfahrttechnik,
Universitaet der Bundeswehr Muenchen, Munich, Germany; Bird, Michael K., Argelander-Institut für
Astronomie, University of Bonn, Bonn, Germany; Imamura, Takeshi, Institute of Space and
Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa, Japan; Paetzold,
Martin, Rheinisches Institut fuer Umweltforschung (RIU), Department of Planetary Research, Cologne,
Germany; Remus, Stefan, ESAC, ESA, Villa Franca, Spain
Next to quasi-horizontal waves and eddies on near planetary scales, diurnally – forced eddies and
thermal tides, small-scale gravity waves and turbulence play a significant role in developing as well as
maintaining the atmospheric superrotation.
With the Venus Express Radio Science Experiment VeRa we retrieved more than 700 atmospheric
profiles in the mesosphere and troposphere of Venus in the approximate altitude range of 40-90 km.
The atmospheric profiles cover a wide range of latitudes and local times, enabling us to study
atmospheric waves phenomena at different spatial scales in the mesosphere and troposphere.
Small-scale temperature variations with vertical wavelengths of 4 km or less have significant wave
amplitudes in the stable atmosphere above the tropopause as compared with the only shallow
temperature perturbations in the adjacent middle cloud layer.
We found evidence for a local time dependence of gravity wave activity in the low latitude range.
Gravity wave amplitudes are at their maximum in the early afternoon, indicating that convection is a
WEDNESDAY, 12 JUNE – PAGE 15 possible wave source. We also found that the gravity wave activity showed a strong latitudinal
dependence with an increase of wave activity with increasing latitude in both hemispheres.
These results suggest that convection (at low latitudes) as well as topographical forcing (at high
northern latitudes), possibly in combination with convection and/or Kelvin-Helmholtz instabilities, are
possible key processes for the generation of gravity waves.
On the other hand, the upper mesosphere in the low latitudes is strongly influenced by thermal tides.
The presence of different wave modes will be investigated.
Abstract Nr. 54
Gravity waves in the Venus upper atmosphere, modelled on VIRTIS/Venus Express data
Migliorini Alessandra, IAPS-INAF, Rome; Altieri Francesca, IAPS-INAF, Rome; Shakun Alexey, IKI,
Space Research Institute, Moscow; Zasova Ludmila, IKI, Space Research Institute, Moscow; Piccioni
Giuseppe, IAPS-INAF, Rome; Drossart Pierre, LESIA, Observatory of Paris, Paris
Gravity waves play a crucial role in atmospheric circulation because they transport energy and
momentum, and influence large scale motions. They can propagate horizontally and vertically, with
the amplitude of the oscillation growing upper ward. They are related to the buoyancy force which lifts
air particles. Then, the vertical displacement of air particles produces density changes that cause
gravity to act as restoring force.
Since gravity waves can induce fluctuations on temperature and density fields, they affect the airglow
intensities. Double peaked O2 profiles are possible evidences of gravity waves vertically propagating,
and they are often observed with VIRTIS instrument in the night side of Venus. In analogy to the
Earth’s and Mars cases, we use a well known theory to model the O2 nightglow emissions affected by
gravity waves propagation, to investigate the waves properties in the upper atmosphere of Venus.
Here we propose a statistical discussion of the gravity waves characteristics, like vertical wavelength
and wave amplitude, with respect to local time and latitude.
Abstract Nr. 91
Thermal structure of the upper atmosphere of Venus with SPICAV/VEx data
Piccialli A. , LATMOS-UVSQ, Guyancourt, France
Venus upper atmosphere (80-140 km altitude) is one of the most interesting regions on the planet. It
is a transition region characterized by a complex dynamic: strong retrograde zonal winds dominate
the lower mesosphere while a solar-antisolar circulation can be observed in the upper
mesosphere/lower thermosphere. The SPICAV (Spectroscopy for the investigation of the
characteristics of the atmosphere of Venus) instrument operates on board the ESA orbiting platform
Venus Express since 2006. It is a remote sensing spectrometer covering distinct spectral regions in
ultraviolet (118–320 nm) and near-infrared (650–1700 nm). In the stellar occultation mode the UV
sensor is particularly well suited to measure the vertical profiles of CO2, temperature, SO2, SO, clouds
and aerosols of the middle and upper atmosphere of Venus. We will present a preliminary study of
Venus atmospheric structure between 80 and 140 km using SPICAV-UV stellar occultation
observations. A very large dataset has been collected by SPICAV-UV that consists of more than 500
stellar occultation profiles performed at all latitudes and seasons during nighttime. The upper
atmosphere of Venus shows a very large temporal variability, variations both orbit-to-orbit and with
local time are observed. A permanent warm area appears distinctly at the mesopause at about 90-100
km of altitude which was never observed before Venus Express. As first explanation, this feature is
interpreted as the result of adiabatic heating in the downwelling branch of the solar-antisolar
thermospheric circulation on the night side.
Abstract Nr. 59
CO2 rotational temperatures compared to hydrostatic temperatures obtained with the SOIR
instrument on board VEx
WEDNESDAY, 12 JUNE – PAGE 16 Mahieux Arnaud, Belgian Institute for Space Aeronomy; Wilquet Valérie, Belgian Institute for Space
Aeronomy; Vandaele Ann Carine, Belgian Institute for Space Aeronomy; Robert Séverine, Belgian
Institute for Space Aeronomy; Drummond Rachel,Belgian Institute for Space Aeronomy; Lopez
Valverde Miguel, Instituto de Astrofísica de Andalucía/CSIC; Lopez Puertas Manuel, Instituto de
Astrofísica de Andalucía/CSIC; Funke Bernd, Instituto de Astrofísica de Andalucía/CSIC; Bertaux JeanLoup,LATMOS/CNRS
The SOIR instrument performs solar occultation measurements in the IR region (2.2 - 4.3 µm) at a
resolution of 0.12 cm-1, the highest of all instruments on board Venus Express. It combines an echelle
spectrometer and an AOTF (Acousto-Optical Tunable Filter) for the order selection.
The wavelength range probed by SOIR allows a detailed chemical inventory of the Venus atmosphere
at the terminator in the upper mesosphere and lower thermosphere (70 to 170 km) with an emphasis
on vertical distribution of the gases. In particular, measurements of CO2 density vertical profiles have
been routinely performed. From these density measurements, kinetic temperature profiles are derived
using the hydrostatic equilibrium. A permanent cold layer is observed at the mesopause (~ 120 km).
A different and independent method is developed here, making use of the information obtained from
the rotational structure of the CO2 bands to derive rotational temperature profiles. The rotational
temperature profiles are compared to the hydrostatic temperature profiles, and they confirm the
presence of the cold layer at the mesopause. At higher altitudes (above 140 km) there are systematic
differences between them, although the sensitivity to the rotational structure is smaller. These
differences will be discussed in view of the non-LTE theory, and in order to design future observations
with SOIR.
Abstract Nr. 25
Incorporation of a gravity wave momentum deposition parameterization into the Venus
thermosphere general circulation Model (VTGCM)
Zalucha, Angela, SETI Institute; Brecht, Amanda, NASA Ames Research Center; Rafkin,
Scot, Southwest Research Institute; Bougher, Steve, University of Michigan; Alexander,
Joan, NorthWest Research Associates - CoRA
The gravity wave drag parameterization of Alexander and Dunkerton [1999] was implemented into a
Venus Thermosphere General Circulation Model (VTGCM) to investigate breaking gravity waves as a
source of momentum deposition in Venus' thermosphere. Previously, deceleration of zonal jets on the
morning and evening terminators in models was accomplished via Rayleigh friction, a linear drag law
that is not directly linked to any physical mechanism. The Alexander and Dunkerton [1999]
parameterization deposits all of the momentum of a breaking wave at the breaking altitude and
features a spectrum of wave phase speeds whose amplitudes are distributed as a Gaussian about a
center phase speed. We did not find a combination of wave parameters (namely center phase speed,
amplitude at center phase speed, and distribution width) to produce sufficient drag in the jet cores
that would bring VTGCM density and nightglow emissions into agreement with Venus Express
observations. Gravity waves launched below 100 km either break in the strong shear zones below 115
km or are reflected, and do not propagate into the jet core regions where drag is needed. However, if
the condition of total internal reflection of high frequency waves was removed, waves were able to
penetrate the jet cores. The results we present demonstrate that the physics of gravity wave schemes
developed for the middle atmosphere may not be appropriate for the thermosphere and that damping
mechanisms other than nonlinear breaking/saturation dominate and should be accounted for at these
heights.
Abstract Nr. 110
Retrieval of temperature and carbon monoxide from the 4.7um limb non-LTE emission of
the upper atmosphere measured by VIRTIS/Venus Express
López-Valverde, Miguel A., IAA/CSIC, Granada (Spain); Gilli, Gabriella, IAA/CSIC, Granada (Spain);
Peralta, Javier, IAA/CSIC, Granada (Spain); Bougher, Stephen W., Univ. of Michigan, Ann Harbour
WEDNESDAY, 12 JUNE – PAGE 17 (USA); Brecht, Amanda, NASA-Ames Research Center (USA); Drossart, Pierre, LESIA, Observatoire de
Paris (France); Piccioni, Giuseppe, IAPS, Rome (Italy)
Solar fluorescence is a form of breakdown of Local Thermodynamic Equilibrium (LTE) which greatly
enhances the molecular IR emissions in the upper atmospheres of the planets. An example if the
daytime emission by atmospheric CO at 4.7 um in the terrestrial planets, and recently observed by
VIRTIS/VEx in the limb of Venus at 100-150 km tangent altitudes. We will present this data set, its
analysis and inversion, and a first comparison with the VTGCM predictions.
The data was binned in order to improve SNR, which unfortunately is not large and this reduced the
latitude and local time resolution of the final dataset. The data was also binned in altitude, in 10-km
boxes, although the weighting functions are even broader.
The intensity of the emission carries information on the CO abundance while the rotational structure
revealed by VIRTIS contains information on the kinetic temperature. We designed a retrieval scheme
to obtain CO and temperature simultaneously. The main non-LTE effects (solar illumination, radiative
transfer, collisions with CO2 non-LTE populations) were taken into account in the forward model,
which includes a detailed non-LTE model for CO2 and CO populations in Venus. Despite the large data
averages the resulting spectra are noisy, but this dataset supply a new and valuable insight into the
upper mesosphere and lower themosphere of Venus. We will present the Latitude and LocalTime
variations of the CO and temperature obtained and analyze them with the help of similarly boxed data
from dedicated VTGCM simulations.
Abstract Nr. 113
Earth based Doppler-wind and temperature measurements in Venus upper atmosphere
using the infrared heterodyne spectrometer THIS.
Sornig Manuela, RIU-PF at the University of Cologne
Dynamics of the Venusian atmospheric transition zone between the subsolar to anti-solar (SS-AS) flow dominated region above 120km and the
superrotation dominated region below 90 km is not yet fully understood.
Temperatures in the same region are not very well constrained and we lack
in a comprehensive understanding of this atmospheric region. Therefore
measurements of these parameters on various time scales and on different
locations on the planet are essential for validation of global circulation
models and a comprehensive understanding of the atmosphere. Such
observations can be provided by the Cologne infrared heterodyne
spectrometer THIS. Operating around 10μm THIS fully resolves CO2 non-LTE
emission lines for Doppler-wind and temperature retrievals at an pressure
level of 1μbar (~110km). In addition broader CO2 absorption lines can be
used to gain information about the temperature profile lower down in the
atmosphere (~60-90 km). Doppler-wind velocities and temperature results
including a report about wave activities from campaigns between 2007 to
2013 will be presented.
Abstract Nr. 37
Doppler Winds Mapped around the Lower Thermospheric Terminator of Venus: JCMT
Observations of the 2012 Solar Transit
R Todd Clancy, Space Science Institute; Brad Sandor, Space Science Institute; James Hoge, National
WEDNESDAY, 12 JUNE – PAGE 18 Research Council of Canada, Joint Astronomy Center
Doppler shifts of sub-millimeter 12CO (346 GHz) and 13CO (330 GHz), and millimeter 12CO (230
GHz) line absorptions were mapped around the circumdisk terminator of Venus during the June 5,
2012 solar transit, employing the James Clerk Maxwell Telescope (JCMT). Radiative transfer analysis
of these thermal line absorptions yields cross-terminator winds in the Venus lower thermosphere
(100-120km) over the local time (LT) and latitude extent of the atmospheric limb presented by the
inferior conjunction, nightside apparent disk of Venus. The unique solar transit geometry provides
enhanced spatial resolution of the terminator associated with solar illumination of this atmospheric
limb region, and so provides the first characterization of the instantaneous distribution of cross
terminator flow in the Venus lower thermosphere versus LT and latitude. Furthermore, by mapping
Doppler winds over the nightside disk preceding and following the solar transit, we place the highly
variable zonal and subsolar-to-antisolar (SSAS) circulation components of the nightside lower
thermosphere (Clancy et al, 2012) in the context of the day-to-night cross terminator flow that drives
this chaotic nightside dynamical regime. The solar transit observations indicate substantially
supersonic (150-290 m/s) day-to-night cross terminator winds that vary by as much as 50% over a
one hour timescale and are significantly (by 20-140 m/s) stronger over the evening versus the
morning terminator. These behaviors likely contribute to both the variability and the apparent
retrograde zonal component of circulation in the Venus nightside upper atmosphere. They also support
dynamical arguments for preferential deceleration of the morning sector SSAS circulation due to
momemtum deposition associated with gravity waves propogating from the lower atmosphere
(Alexander, 1992).
Abstract Nr. 11
Venus night side measurements of winds at 115 km altitude from NO bright patches
tracking.
Bertaux Jean-Loup, LATMOS,UVSQ,CNRS; Gérard Jean-Claude, LPAP, Université de Liège; Stiepen,
Arnaud, LPAP, Université de Liège; Marcq, Emmanuel, LATMOS,UVSQ,CNRS; Montmessin,
Franck, LATMOS,UVSQ,CNRS; Dalaudier, Francis,LATMOS,UVSQ,CNRS; Hauchecorne,
Alain, LATMOS,UVSQ,CNRS; Segret, Boris, LATMOS,UVSQ,CNRS
The UV NO emission on the night side is due to air transported from day to night in the
thermospheric circulation and recombination of N+O atoms. Both Pioneer Venus (1978)
and SPICAV/VEX show that the statistical center of the emission is off towards morning
from the anti-solar point, as if it were pushed by super-rotation.
However, the emission takes place at 115 km, while VIRTIS/VEX, with maps of
O2 emission (peak altitude 95 km) in the night side of Venus (recombination of O+O),
has shown that the maximum of emission is statistically centered on the antisolar point.
Therefore, there is no influence of super-rotation at 95 km. One way to explain this
paradox is that the cause of the super rotation is different at 115 km and in the lower
atmosphere. Alternately, some gravity waves could propagate from below, crossing the
altitude 95 km with minimal interaction, and breaking around 115 km, depositing their
momentum.
Also, the altitude of N2 photo-dissociation is higher in the thermosphere than CO2,
therefore the thermospheric circulation pattern may be different for the transport of N
atoms, and O atoms.
We have started building maps of the NO emission with VEX. The idea is that NO
emission is concentrated generally in rather well defined patches of light. Therefore, by
comparing maps taken at 1 hour or 24 hr interval, we can make a “bright patch
tracking”, and derive directly the velocity of the moving air parcel containing N and O, or
WEDNESDAY, 12 JUNE – PAGE 19 the wave velocity if relevant to the emission.
Abstract Nr. 29
Venus nitric oxide nightglow distribution: a clue to thermospheric dynamics
Stiepen Arnaud, Université de Liège - Laboratoire de Physique Atmosphérique et Planétaire; Gérard
Jean-Claude, Université de Liège - LPAP; Dumont Maïté, Université de Liège - LPAP; Cox
Cédric, Université de Liège - LPAP; Bertaux Jean-Loup, Laboratoire Atmosphères, Milieux,
Observations Spatiales (LATMOS)
Nitric oxide δ and γ emissions on the nightside of Venus have been extensively observed by SPICAV
on board Venus Express. They arise from radiative recombination of O(3P) and N(4S) atoms produced
on the dayside of the planet through photodissociation of CO2 and N2. These atoms are carried to the
nightside by the global subsolar to antisolar circulation.
We analyze a wide dataset of nadir observations obtained during low to medium solar conditions to
determine the statistical distribution of the NO nightglow. This global map is the first one since the
Pioneer Venus era 35 years ago. It is fully compatible with it in spite of the different solar activity
level. The NO airglow emission shows a statistical bright region extending from 01:00 to 03:30 local
time and -25° to 10° latitude. The mean intensity within this region is 3.9kR, and the hemispheric
intensity is 1.9 kR. Intensities as high as ~20 kR have been observed on some occasions.
The location of the statistical brightest region of the NO emission raises key questions about the
dynamics in the thermosphere. Superrotation is observed at cloud top level (~70 km) but disappears
at the altitude of the O2(a1Δ) emission (~95 km). It is present again in the lower thermosphere with
the NO emission at 115 km and at high altitude with the He bulge at ~250 km. This statistical view is
completed by individual latitudinal cuts that occasionally show multiple emission peaks within the
bright region.
Abstract Nr. 125
The O2 nightglow from VIRTIS-M VEX measurements
Zasova Ludmila, IKI RAS, Moscow, MIPT, Dolgoprudny, Russia; Gorinov Dmitry, IKI RAS, Moscow,
MIPT, Dolgoprudny, Russia; Khatuntsev Igor, IKI RAS, Moscow, MIPT, Dolgoprudny, Russia; Ignatiev
Nikilay, IKI RAS, Moscow, MIPT, Dolgoprudny, Russia; Altieri Francesca, IASP-INAF, Rome, Italy;
Migliorini Alessandra, IASP-INAF, Rome, Italy; Piccioni Guseppe, IASP-INAF, Rome, Italy; Drossart
Pierre, LESIA, Paris, France
We continue a study of the O2 night glow from VIRTIS-M spectra. The main topic is vertical and
horizontal distribution of the emission. It was found that horizontal distribution of global intensity of
the O2 emission correlates with measured from movement of the O2 features wind speed. Areas of
high positive values of horizontal divergence of the flow correspond to the minimum intensity of the
airglow and vice versa, negative values (meaning a convergence) coincide with the maxima intensity
of airglow. Maximal wind speed, observed at the morning side, corresponds to the minimum intensity
in the global map. Temperature global map, retrieved from the 4.3 μm CO2 band of VIRTIS spectra
(Grassi&Migliorini), T(φ,LT), also reveal a temperature minimum at 90-100 km, coinciding in position
with minimum intensity of O2 and maximum of horizontal wind speed. In spite of this intrinsically not
contradictory picture, horizontal distribution of the O2 nightglow cannot be explained within well
known modes of circulation of Venus atmosphere: zonal retrograde superrotation and SS-AS flow.
Abstract Nr. 22
Latitudinal variations of the altitude of the Venus O2 airglow observed with VIRTIS-M: a
signature of dynamical processes in the upper atmosphere
WEDNESDAY, 12 JUNE – PAGE 20 Jean-Claude Gérard, LPAP - Université de Liège; Lauriane Soret, LPAP - Université de Liège; Giuseppe
Piccioni, IAPS-INAF Roma; Pierre Drossart, Observatoire de Paris - Meudon
The VIRTIS-M multispectral imager measured the characteristics of the nightside airglow at 1.27 μm
between 15 May 2006 and 14 October 2008. This emission layer is associated with the recombination
of oxygen atoms formed by dissociation of CO2 molecules on the dayside. The O atoms are
subsequently carried to the nightside by the subsolar to antisolar global circulation where they
recombine to form O2 singlet delta metastable molecules. Images of the Venus limb at 1.27 μm have
been assembled to analyze the two-dimensional (latitude-altitude) distribution in quasi-meridional
cuts through the atmosphere. It is therefore possible to visualize latitudinal changes in the altitude of
the emission. We find that this altitude generally increases toward the north pole. Occasionally, an
abrupt increase of several kilometers is observed in the 60° N region. We use a photochemicaldynamical model to investigate how changes in the vertical transport efficiency can possibly explain
these observations.
Abstract Nr. 52
Modelling of ultraviolet and visible dayglow emissions on Venus
Jain, Sonal Kumar, Space Physics Laboratory, Vikram Sarabhai Space Center, Indian Space Research
Organisation Trivandrum, India; Bhardwaj, Anil, Space Physics Laboratory, Vikram Sarabhai Space
Center, Indian Space Research Organisation Trivandrum, India
We have developed a model to study CO Cameron and N2 triplet bands, CO2+ ultraviolet doublet, and
atomic oxygen ultraviolet (2972 Å) and visible (5577 and 6300 Å) line emissions on Venus for low,
moderate, and high solar activity conditions. Our calculation suggests that CO Cameron band in
Venusian dayglow is mainly produced by electron impact excitation of CO (e-CO) followed by electron
and photon impact dissociative excitation of CO2. For solar moderate (F10.7 = 130) condition, CO
Cameron band and CO2+ UV doublet emissions maximize at 135 km with intensities of 2300 kR and
330 kR, respectively. The calculated intensities are in agreement with the recent SPICAV/Venus
Express observation . The overhead intensity of N2 Vegard-Kaplan (VK) bands in wavelength ranges
4000-8000, 3000-1900, 2000-3000, and 1500-2000 Å are 22%, 39%, 35%, and 4% of the total VK
band emission. Emissions between 6000 and 8000 Å wavelength consist of about 50% of the total
First Positive band system, while 90% of Second Positive band system is due to the emissions lie in
wavelengths between 3000 and 4000 Å. The calculated intensity of N2 VK band on Venus is about an
order of magnitude higher than that on Mars due to higher abundance of N2 on Venus and small
heliocentric distance of Venus. Densities of O(1S) and O(1D), and height-integrated overhead and line
of sight (limb) intensities of OI 2972, 5577, and 6300 Å emissions are calculated on Venus. The
results will be presented and discussed.
Abstract Nr. 121
Coordinated Sounding Rocket, HST, and SPICAV Observations of Venus in Nov. 2013
Clarke, John T , Boston University; Bertaux, Jean-Loup, LATMOS and BU; Carveth, Carol, Boston
University; Chaufray, Jean-Yves, LATMOS; Gladstone, Randy, SwRI; Darling, Nathan, Boston
University
A coordinated set of observations of Venus in Nov. 2013 will address the escape of water from the
upper atmosphere as related to measurements of the ratio of deuterium to hydrogen at various
altitude levels. The observations will be performed by the Venus Spectral Rocket (VeSpR) sounding
rocket experiment, the HST Space Telescope Imaging Spectrograph (STIS), and the SPICAV/SOIR
instruments on Venus Express. The VeSpR experiment is a high spectral resolution system designed
specifically to resolve the D and H Ly alpha emissions from planetary atmospheres. The present
version of this payload will measure the D/H ratio at the level above CO2 photo-absorption, or above
roughly 110 km altitude. Similar observations are now permitted using the HST/STIS in echelle mode,
where previously HST observations of Venus were not allowed. The SOIR instrument has previously
measured the ratio of HDO/H2O in the middle atmosphere between 70-110 km, and found a variation
WEDNESDAY, 12 JUNE – PAGE 21 with altitude in the D/H ratio. New observations will be made for comparison with the other
instruments. The goal is to understand the path that both D and H atoms take as water is
photodissociated, and the atoms move to the top of the atmosphere where they can escape into
space. The detailed physical processes must be understood to know how to relate the measured tow
order of magnitude enhancement in the Venusian D/H ratio to the historic escape of a volume of water
from the early atmosphere.
WEDNESDAY, 12 JUNE – PAGE 22 Thursday, 13 June Abstract Nr. 03
Ground-based observations of minor species on Venus using infrared spectroscopy
T. Encrenaz, LESIA, Paris Observatory, France; T. Greathouse, SwRI, San Antonio, TX, USA; M.
Richter, Physics Department, UC Davis, CA, USA; J. Lacy, Dept. of Astronomy, University of Texas,
Austin, TX, USA; B. Bézard, LESIA, Paris Observatory, France; T. Fouchet, LESIA, Paris Observatory,
France; T. Widemann, LESIA, Paris Observatory, France
Sulfur dioxide and water vapor on Venus have been monitored using Venus Express and results
suggest significant spatial and temporal variations. Ground-based imaging spectroscopy at high
spectral resolution provides a complementary method to study minor species over and within the
clouds. This method is well suited for studying latitudinal or day/night variations because, unlike
in-orbit observations, global instantaneous maps of minor species can be recorded. In this talk,
we review recent results on minor species from ground-based infrared spectroscopy. In
particular, we present SO2 and H2O maps obtained with the TEXES high-resolution imaging
spectrometer at the NASA Infrared Telescope Facility (IRTF). Two observing runs took place in
January and October 2012, respectively, at 7 microns and 19 microns, with a resolving power of
about 70000 and a spatial resolution of about 1.5 arcsec. The 7-microns radiation probes the
cloud top, while the 20-microns radiation probes a few kilometers below. Both HDO and
SO2 were identified in our spectra. Water maps show that H2O is globally uniform over the disk,
with a mean mixing ratio of 1.5 ppm, and no significant temporal change on a timescale of two
days. In contrast, SO2 maps show strong local and temporal variations over a timescale of a day,
with maximum values of about 100 ppb (Encrenaz et al. A&A 543, A153, 2012). There is a
significant decrease of the SO2content between the cloud and the lower mesosphere. These
results will be presented and discussed.
Abstract Nr. 04
Sulfur and water mapping in the mesosphere of Venus
T. Encrenaz, LESIA, Paris Observatory, France; R. Moreno, LESIA, Paris Observatory, France; T.
Fouchet, LESIA, Paris Observatory, France; E. Lellouch, LESIA, Paris Observatory, France; A.
Moullet, NRAO, Charlottesville, VA, USA
Both sulfur dioxide and water vapor play a major role in the aeronomy and dynamics of Venus’
atmosphere. In the lower troposphere, their mixing ratios are about 30-50 ppm and 130 ppm, respectively.
At an altitude of about 70 km, they are drastically reduced by photochemistry and by the formation of
H2SO4 clouds. Venus Express UV and IR data, as well as ground-based infrared observations, have
shown evidence for strong local and temporal variations of SO2 at the cloud top and above. At high
altitude (80-90 km), SO2 and SO have been detected by ground-based submillimeter observations. They
show evidence for a drastic increase of the sulfur abundance, implying the probable presence of an upper
mesospheric sulfur-bearing aerosol source. ALMA offers an unprecedented possibility to map H2O and
SO2 with a high spatial resolution (about 1 arcsec) in the 70 – 100 km range, over the disk of Venus.
During Cycle 0, using the compact configuration of ALMA, we have observed Venus in 4 sequences,
each of 30 minutes integration time, on November 14, 15, 26 and 27, 2011. Transitions of CO, SO2, SO
and HDO have been observed simultaneously in the 335-346 GHz frequency range. The diameter of
THURSDAY, 13 JUNE – PAGE 23 Venus was 12 arcsec. In addition to sulfur and water maps, the CO maps will be used for a retrieval of
mesospheric winds. The observations will be presented and discussed.
Abstract Nr. 71
Measurements of minor species at cloud top level
Marcq, Emmanuel, LATMOS / Univ. de Versailles Saint-Quentin; Bertaux, Jean-Loup, LATMOS / CNRS;
Montmessin, Franck,LATMOS / CNRS; Belyaev, Denis, LATMOS / IKI; Encrenaz, Thérèse, LESIA /
CNRS
The top of the clouds is a transitional region between the troposphere and the mesosphere of Venus.
Thus, minor species originating from both domains and very different chemical pathways are able to
reach this region and interact with each other, effectively coupling the lower and upper atmopshere.
These complex chemical interactions are, ultimately, responsible for creating and maintaining the thick
and ubiquitous H2SO4-H2O cloud cover, with far reaching consequences on the chemistry of the whole
atmosphere of course, but also on virtually all the other aspects of this atmopshere (radiative budget,
circulation, surface-atmosphere interactions). Accurate and frequent measurements of key minor
species involved in the major chemical cycles (suflur and carbon, mainly) are therefore crucial for a
better understanding of the Venusian atmosphere.
In this talk, I shall review measurements of two species that our team have conducted recently:
SO2 measurements using SPICAV-UV/Venus Expressin nadir mode [Marcq et al., 2011, 2013], for which
consistent latitudinal variations and temporal variability on a large range of timescales have been
evidenced. We should also provide some simple modeling able to account for these variations using the
LMD-GCM [Lebonnois et al., 2009], at least from a qualitative point of view.
CO measurements using C-SHELL/IRTF. This work is still in progress at the time, but preliminary results
point that CO and CO2 column densities could be measured near 4.5 µm on both day and night sides of
Venus.
Abstract Nr. 50
Water vapor and the cloud top variations in the Venus’ mesosphere from SPICAV
observations
Fedorova Anna, Space Research Institute (IKI); Moscow Institute of Physics and Technology (MIPT);
Bertaux Jean-Loup,LATMOS; Marcq Emmanuel, LATMOS; Korablev Oleg, Space Research Institute
(IKI); Moscow Institute of Physics and Technology (MIPT); Montmessin Franck, LATMOS
SPICAV VIS is an AOTF (acousto-optical tunable filter) spectrometer working in the spectral range of
0.65-1.7 µm onboard the Venus-Express mission. It provides measurements of the H2O abundance
above Venus’ clouds based on the 1.38-µm band and the cloud top altitude based on the CO2 bands in
the range of 1.4-1.6 μm. The new calibrations of the instrument in 2010-2012 allowed updating of
results reported earlier. The cloud top altitude has been routinely retrieved for dataset from 2006 to
2013 (VEx orbits 23-2500) taking into account multiple-scattering in the cloudy atmosphere. The τ=1
level at 1.48 μm varies from 69 to 73 kmat lower latitudes and from 64 to 68 kmat high latitudes near
the Poles. The possible long-term and year-to-year variations were studied. The H2O mixing ratio from
the 1.38 μm band varies from 4 to 12 ppm with larger variations in the lower latitudes which was not
observed by VIRTIS-H from the 2.56 μm H2O band at altitudes of 68-70 km. The 1.38 μm H2O band is
sensitivity to altitudes of 55-70 km and a vertical gradient of water within the upper clouds can be
responsible for the water behavior. The spot pointing observations for wide variations of viewing angle
in the near-IR spectral range are useful to determine the vertical gradient of water within the clouds.
Abstract Nr. 116
Re-analysis of Pioneer Venus SO2 measurements
THURSDAY, 13 JUNE – PAGE 24 McGouldrick, Kevin, University of Colorado Boulder; Esposito, Larry, University of Colorado Boulder
A previous analysis of Pioneer Venus Orbiter Ultraviolet Spectrometer (PVOUVS) data at wavelengths
of 207nm and 237nm by Esposito et al. (1988) suggested a significant decline in SO2 concentration at
40mb occurred over the course of a decade between 1979 and 1988. More recent observations of
Venus made by ultraviolet spectrometers on Venus Express and ground based heterodyne
spectroscopy suggest that SO2 concentrations at 40mb in the Venus atmosphere of today is closer to
the values obtained near the start of the Pioneer Venus mission, and/or suggest the existence of an
increase in SO2 concentration at higher altitudes (above about 1mb). The Pioneer Venus Ultraviolet
Spectrometer exhibited a spectral range from about 110nm to about 330nm. We have been
attempting to incorporate the data from these additional wavelenghts to further constrain the
SO2 measurements that can be derived from observations carried out by Pioneer Venus during its
lifetime. We present results of a re-analysis of the PVOUVS data from the first 500 orbits of the
Pioneer Venus mission that take into account the new knowledge of the Venus upper atmosphere that
has been gained in the last twenty years, including the advances driven by the observations made by
ESA's Venus Express spacecraft, in orbit since 2006.
Abstract Nr. 98
Assessing An Impact Hypothesis for Upper Atmosphere Abundance Variations on Venus
Grinspoon David, NASA/Library of Congress; Glaze Lori, NASA/GSFC
Observed sulfur dioxide variations in the upper atmosphere of Venus have been attributed to either
volcanic injection or dynamical overturn. In theory the impact of small comets could also produce
such a signature. Because the below-cloud atmosphere is much richer in SO2, a rising impact fireball
could temporarily inject substantial SO2 above the clouds. In the case of the SL-9 impact on Jupiter
such an effect was observed, post-impact. We will present estimates of the cometary mass required
and the expectation frequency for an impact of the appropriate magnitude, in order to assess the
likelihood of this explanation for any observed variations in upper atmosphere composition.
Abstract Nr. 75
Positive Correlation of SO, SO2 in the Dayside Venus Mesosphere: Identification of Diurnal
SOx Partitioning from JCMT Submm Spectroscopy
Sandor, Brad, Space Science Institute; Clancy, Todd, Space Science Institute; Mills,
Franklin, Australian National University and Space Science Institute
Sub-mm spectroscopic observations of the Venus upper mesospheric indicate SO and SO2 abundances
have comparable magnitude in the dayside atmosphere,with correlation coefficient 0.9. On the
nightside, SO abundances are always small,such that the SO/SO2 ratio is near zero. Since 2004,
submm spectroscopy with the James Clerk Maxwell Telescope (JCMT) has been used to measure
abundances of SO2 (346.652 GHz) and SO (346.528 GHz) in the Venus mesosphere. The two
molecules are observed simultaneously (same bandpass). Altitude resolution (70-100 km sensitivity)
is retrieved from shape of the pressure-broadened absorption lines, indicating an inversion with far
more SOx above 85 km than below. Total abundance (SO + SO2) exhibits strong, unexplained time
variability both day and night. However, the SO/SO2 ratio varies diurnally, with value roughly 1.0 on
dayside, and near zero at night. Maximum total abundances (SO + SO2) are similar (70 ppb) on day
and night sides, with no evidence this sum has diurnal dependence. We suggest SO2 photolysis,
balanced by unknown recombination reactions is responsible for dayside partitioning of SOx into SO
and SO2, while the total SOx exhibits secular, but not diurnal variation. Empirically, diurnal SOx
partitioning in the Venus mesosphere has many terrestrial atmospheric analogs which are
photochemically well understood. Details of Venus SOx partitioning are undoubtedly much different
from those of any terrestrial case. However, discovery and characterization of this pattern in Venus
SOx provides a critical constraint to photochemical modeling of the Venus mesosphere.
Abstract Nr. 103
THURSDAY, 13 JUNE – PAGE 25 Temporal, Spatial Variation of HCl in the Venus Mesosphere, based upon Submm
Spectroscopic Observations with JCMT
Sandor, Brad, Space Science Institute; Clancy, Todd, Space Science Institute
Submm spectroscopic observations of Venus mesospheric (70-100 km) HCl (625.9 GHz) were
conducted with the James Clerk Maxwell Telescope (JCMT). Nightside equatorial measurements
(2010) indicate abundances below (but not above) 80 km are consistent with model prediction (eg.
Yung and DeMore, 1982), and with prior low to mid-latitude measurements (eg. Krasnopolsky, 2010;
at 74 km). However, observed submm abundances above 80 km are much smaller than model
values, and reveal strong secular (1 month) time variation at local midnight. Retrieved submm
equatorial profiles are consistent with SOIR polar HCl above 85 km (Vandaele et al., 2008), but show
larger abundances in the lower mesosphere. Agreement between submm and SOIR HCl in the upper
mesosphere provides cross-validation of the two methods, while disagreement in the lower
mesosphere may indicate latitude variation at that altitude. We have suggested (Sandor and Clancy,
2012) downward transport of HCl-poor thermospheric air as a possible mechanism for depleting HCl in
both the polar (SOIR) and nightside equatorial (submm) atmosphere. However, early analysis of the
first (March, 2013) submm dayside observations finds consistency with nightside HCl, indicating the
simple downward transport hypothesis is not sufficient. Further, comparison of day/night profiles
indicates any diurnal dependence is significantly weaker than the observed secular nightside variation.
Modest latitude resolution of dayside observations shows no variation of the HCl altitude profile
between equatorial and mid-latitudes.
Abstract Nr. 33
Trace gases in the mesosphere and lower thermosphere of Venus from SOIR/VEX
observations
Vandaele Ann C., IASB-BIRA; Drummond, R., IASB-BIRA; Mahieux, A., IASB-BIRA; Robert, S., IASBBIRA; Wilquet, V., IASB-BIRA; Bertaux, J.-L., LATMOS
The wavelength range probed by SOIR/VEX allows a detailed chemical inventory of the Venus
atmosphere. Several trace gases, such as H2O/HDO, HF, HCl, CO, or SO2, are observed together with
CO2, leading to the derivation of their vertical density profiles. Temperature and total density profiles
are deduced from the CO2 density profiles and VMR are obtained for all trace gases.
The measurements all occur at the Venus terminator, morning and evening sides, covering all
latitudes from the North Pole to the South Pole. The vertical resolution is between 100 and 500 m in
the Northern hemisphere, and is poorer at southern latitudes (between 1 and 2.5 km). The typical
vertical extent of the profiles ranges from 70 to 120 km (for CO2 : from 70 to 170 km), encompassing
thus the mesosphere and the lower thermosphere of the planet. The Venus atmospheric region probed
by SOIR is very special as it acts as a transition region between two distinct dynamical regimes
characterized by different flow patterns: the zonal retrograde flow below 70 km and the subsolar to
antisolar circulation above 100 km. Some of the detected trace gases play important roles in the
chemistry of the atmosphere. The study of CO, being mainly produced through the photodissociation
of CO2 at high altitudes by solar ultraviolet radiation, can lead to significant information on the
dynamics taking place in this region.
Results from SOIR observations of trace gases will be presented and discussed. We will report and
analyze short and long term time variations. The latitudinal dependency will also be investigated.
Abstract Nr. 32
Contribution of the SOIR/VEX instrument to VIRA II
Vandaele Ann C., IASB-BIRA; Drummond, R., IASB-BIRA; Mahieux, IASB-BIRA; Robert, IASB-BIRA;
Wilquet, IASB-BIRA; Belyaev, IKI; Fedorova, IKI; Montmessin, LATMOS; Bertaux, LATMOS
The SOIR instrument on-board Venus Express performs solar occultation measurements in the IR
THURSDAY, 13 JUNE – PAGE 26 -1
region (2.2 - 4.4 mm) at a resolution of 0.12 cm . It combines an echelle spectrometer and an AOTF
(Acousto-Optical Tunable Filter) for the selection of the wavelength range.
Several trace gases, such as H2O and its isotopologue HDO, HF, HCl, CO, or SO2, are measured
together with CO2 in the SOIR wavelength range. Vertical density profiles (from 70 to 170 km)
together with the temperature and total density profiles, allow the determination of VMR vertical
profiles. The measurements all occur at the Venus terminator, both the morning and evening side,
covering all latitudes from the North Pole to the South Pole. The vertical resolution is very good from
the North Pole to 40° North (resolution between 100m to 500 m), and is poorer in the Southern
hemisphere (resolution between 1 and 2.5 km). Aerosol extinction vertical profiles are also routinely
monitored, leading to some information on the characteristics of the aerosols present.
We will present some results concerning the observations of CO2, temperature, trace gases and
aerosols as well as data available to build information on the structure and dynamics of the Venus
atmosphere. The possible contribution to VIRA II will be discussed.
Abstract Nr. 36
SPICAV-SOIR mesospheric aerosols observations and modelling
Wilquet Valérie, IASB-BIRA; Daerden Frank, IASB-BIRA; Drummond Rachel, IASB-BIRA; Mahieux
Arnaud, IASB-BIRA; Robert Séverine, IASB-BIRA; Vandaele Ann Carine, IASB-BIRA; Montmessin
Franck, LATMOS-IPSL; Bertaux Jean-Loup, LATMOS-IPSL
The SPICAV-SOIR instrument on-board VEX performs coordinated solar occultation measurements
with SPICAV-UV (118–320 nm), SPICAV-IR (0.65–1.7 µm,) and SOIR (2.2 - 4.4 µm) and is able to
target the layer of aerosols above the clouds at the terminator. From independent retrievals for each
channel, it has been postulated that the upper haze on Venus includes, in some instances, a bimodal
population, one type of particles with a radius comprised between ~0.1 and 0.3 µm and the second
type, detected in the IR, with a radius varying between ~0.4 and 1 µm. In addition, a high temporal
variability in the aerosol loading was inferred from SOIR observations over 4 years, as well as a
latitudinal dependency.
We propose to refine the size distribution retrieval of aerosols based on the Mie theory and on the
observed spectral dependence of light extinction in the spectra through a unique retrieval procedure
combining the data from the 3 channels of the instrument. We will also search for a dependence on
altitude of the aerosol particles size distribution and of aerosol composition and compare the
variations in aerosol loading to other key parameters retrieved such as water and SO2composition or
temperature.
We also aim at developing a microphysical model to calculate the time dependent haze particle size
distributions assuming an initial size distribution of background aerosols. The model would simulate
the formation, growth, evaporation, and sedimentation of particles. Results of this on-going research
will be presented and discussed.
Abstract Nr. 129
Venus cloud morphology: monitoring by the VMC/ Venus Express camera continued
Dmitrij Titov, ESA/ ESTEC
Venus Monitoring Camera (VMC) onboard the ESA Venus Express spacecraft continues investigations
of the cloud morphology in ultraviolet, visible, and near-IR spectral bands with spatial resolution from
50 km at apocentre to a few hundred of meters at pericentre. The imaging shows strong spatial and
latitudinal variations of the cloud pattern and significant temporal changes on all scales. The camera
discovered new cloud features like bright “lace clouds” and cloud columns at the low latitudes, dark
polar oval and narrow circular and spiral “grooves” in the polar regions, different types of waves at the
high latitudes. The VMC observations revealed detailed structure of the sub-solar region and the
afternoon convective wake, the bow-shape features and convective cells, the mid-latitude transition
region and the “polar cap”. Besides the cloud morphology the VMC observations have important
implications for the problems of the unknown UV absorber, microphysical processes, dynamics and
THURSDAY, 13 JUNE – PAGE 27 radiative energy balance at the cloud tops. We will present an overview of the recent VMC
observations and compare them to the earlier results.
Abstract Nr. 24
Physical properties of particles in the upper clouds of Venus from the IR and UV images
taken by VMC/VEx at small phase angles
Petrova Elena, Space Research Institute, Moscow, Russia ; Shalygina Oksana, Max-Planck-Institut für
Sonnensystemforschung, Katlenburg-Lindau, Germany; Markiewicz , Wojciech
The cause of the difference in brightness of the UV features in the upper clouds of Venus still remains
unknown. The glory feature observed by VMC/VEx at small phase angles allows us to determine the
size of cloud particles and their refractive index. The analysis of the limited information available for
the cases, when the UV contrasts are seen near the glory features allowed for further constraints of
the cloud properties. First, it was found that some UV contrasts observed near the equator at the local
noon are caused by variations (less than 10%) in the amount of submicron absorbing particles (or in
their absorbing properties). Second, from variations of the angular position of the glory maximum in
the UV phase profiles observed before the local noon, the decrease of the effective radii of sulfuric acid
droplets (from 1.05 to 0.9 micron) in the upper cloud layer with increasing latitude (from 40S to 60S)
was revealed. The increase in the amount of 0.9-micron particles may also cause the UV-bright
features often observed at about 50S.
Abstract Nr. 96
Temporal variation of UV reflectivity of Venus: VEX/VMC data analysis
George L. Hashimoto, Okayama University; Manabu Yamada, Chiba Institute of Technology; Takehiko
Satoh, ISAS/JAXA
We examined a temporal variability in ultraviolet reflectivity of Venus using images obtained by the
Venus Monitoring Camera (VMC) on board the Venus Express spacecraft. It is a well known fact that
there is a spatial variation in the uv reflectivity of Venus. However, temporal variability has not been
well understood. We use a long-term continuous observation of Venus Express which enables us to
examine a temporal variation in the uv reflectivity. VMC observed a reflection of sunlight at 365 nm
wavelength. Since the intensity of reflected light depends on the solar incidence angle and emission
angle, it is necessary to investigate the dependences on these parameters. We calculated a solar
incidence angle and emission angle for each pixel of the images, and determined the dependencies on
the solar incidence angle and emission angle. Our analysis revealed that there is a tempral variation
in the uv reflectivity on the Venus' southern hemisphere.
Abstract Nr. 118
Causes of the bright and dark features at the Venus cloud tops
LW Esposito, LASP, University of Colorado
The Venus clouds show dark UV features and occasional brightenings. I review the physical and
chemical processes proposed to create these features: convection, advection, nucleation,
photochemistry, aerosol growth and fallout. Titov (2008) and others have shown that cloud top height
variations cannot explain the features. I conclude that a volcanic eruption is unlikely to create a bright
spot like that reported by Limaye (2009). The VMC UV channel (Titov etal 2012) has observed many
of these features, and provides an excellent data set. I will compare explanations from Esposito and
Travis (1982), Titov etal, Marcq etal (2013) and Encrenaz etal (2013). The best hope for resolving
these questions is simultaneous remote sensing andin situmeasurements of the cloud regions.
Abstract Nr. 130
THURSDAY, 13 JUNE – PAGE 28 On the origin of the 1-micron contrast features in Venus clouds
Takehiko Satoh, ISAS/JAXA
Though week, contrast features in Venus clouds at a wavelength of 1 um have been known since they
were imaged with Galileo/SSI during its flyby to Venus. They somewhat resemble more prominent
markings seen in the ultraviolet but move with different (slower) speed, indicating the 1-micron
contrast features may originate from lower altitudes than the UV markings. We are motivated to carry
out correlative study of the UV, visible, and near IR (1 micron) data to quantitatively understand from
which level these features originate. Such information will tell us the vertical profile of absorption, the
driving force of the atmospheric motion. At this workshop, we report some preliminary results of
radiative transfer modeling and cloud-tracking analysis.
Abstract Nr. 48
Modeling the clouds on Venus: model development and improvement of a nucleation
parameterization
Määttänen Anni, Centre National de la Recherche Scientifique, Université Versailles Saint Quentin,
Laboratoire Atmosphères, Milieux, Observations Spatiales, Guyancourt, France; Bekki Slimane, Centre
National de la Recherche Scientifique, Université Versailles Saint Quentin, Laboratoire Atmosphères,
Milieux, Observations Spatiales, Guyancourt, France; Vehkamäki Hanna,Department of Physics,
University of Helsinki, Helsinki, Finland; Julin Jan, Department of Physics, University of Helsinki,
Helsinki, Finland, presently at: Department of Applied Environmental Science and Bert Bolin Centre for
Climate Research, SE-10691 Stockholm, Stockholm University, Sweden; Montmessin Franck, Centre
National de la Recherche Scientifique, Université Versailles Saint Quentin, Laboratoire Atmosphères,
Milieux, Observations Spatiales, Guyancourt, France; Ortega, Ismael K.,Department of Physics,
University of Helsinki, Helsinki, Finland; Lebonnois Sébastien, Laboratoire de météorologie dynamique,
Centre national de la recherche scientifique, Université Pierre et Marie Curie, Paris, France
As both the clouds of Venus and aerosols in the Earth's stratosphere are composed of sulfuric acid
droplets, we use a model [1,4] developed for stratospheric aerosols and clouds to study the clouds on
Venus. The model describes key microphysical processes including a parameterization for twocomponent nucleation [8] of water and sulfuric acid, condensation/evaporation, and sedimentation.
Coagulation and turbulent diffusion are being added in the 1-D version of the model. Since the model
describes explicitly the size distribution with tens of size bins (50-500), it can handle multiple particle
modes. The existing nucleation parameterization [7] has been improved to cover the very low relative
humidity (RH) found in the atmosphere of Venus. We have made several modifications to improve the
2002 model [7], most notably ensuring that the two-component model behaves as predicted by the
analytical studies at the one-component limit reached at extremely low RH. We have also chosen to
use a self-consistent cluster distribution [9], constrained by scaling it to recent quantum chemistry
calculations [3]. First tests of the model have been carried out with temperature profiles from VIRA
[2] and from the LMD Venus GCM [5], and with a compilation of water vapor and sulfuric acid profiles,
as in [6]. Preliminary results are evaluated against observations.
[1] Jumelet et al., JGR, 2009. [2] Kliore et al., 1986. [3] Kurtén et al., BER, 2007 [4] Larsen et al.,
JGR, 2000. [5] Lebonnois et al. JGR, 2010. [6] McGouldrick and Toon, Icarus 191, 2007. [7]
Vehkamäki et al. JGR, 2002 [9] Wilemski and Wyslouzil, J.Chem.Phys. 1995.
Abstract Nr. 81
Latitudinal and local time dependence of Venus's cloud-level convection
Takeshi Imamura, Japan Aerospace Exploration Agency, Japan; Takehito Higuchi, The University of
Tokyo, Japan; Yasumitsu Maejima, Meteorological Research Institute, Japan; Masahiro Takagi, Kyoto
Sangyo University, Japan; Norihiko Sugimoto, Keio University, Japan; Kohei Ikeda, Japan Agency for
Marine-Earth Science and Technology, Japan
On Venus, in a manner analogous to the Earth, the energy fluxes of incoming solar radiation and
THURSDAY, 13 JUNE – PAGE 29 outgoing thermal IR radiation do not balance each other out at each latitude: low latitudes are
subjected to excessive solar heating, while high latitudes are subjected to excessive IR cooling. Such
energy imbalance should affect the structure of the cloud-level convection. Excessive heating and
cooling occur also periodically with the period of the atmospheric super-rotation, because irradiation to
a certain cloud-level air changes as the air is advected by the super-rotation. We constructed a twodimensional numerical model of Venus’s cloud-level convection and studied the latitude dependence
and the diurnal variation of the convection stucture. IR heating and cooling are taken from a onedimensional radiative-convective equilibrium calculation for a globally-averaged condition, and solar
heating is given as a function of the local time and the latitude. The result shows a remarkable
variation of the structure of convection with latitude and local time. The suggested latitudinal variation
is qualitatively consistent with observed features of the convection layer depth and the activity of
atmospheric waves.
Abstract Nr. 105
Cloud top variations from Venus Express measurements
Ignatiev Nikolay, IKI-RAS; Piccioni Giuseppe, IAPS-INAF; Drossart Pierre, Observatoire de Paris –
Meudon; Titov Dmitri, ESA-ESTEC; Markiewicz Wojciech, MPS; Khatuntsev Igor, IKI-RAS
Simultaneous observations on the dayside of Venus with VIRTIS-M and VMC instruments onboard
Venus Express have been used to map the cloud top altitude and to search for its possible correlation
with the UV absorption (Ignatiev et al., 2009, JGR 114, E00B43). Despite a very non-uniform view of
Venus in the UV, the location of the upper boundary of the clouds, derived from the observation of the
absorption bands in the reflected IR spectrum, demonstrates a smooth systematic behavior with the
latitudinal trends symmetric with respect to equator. A comparison of the first work with the
measurements made with the high resolution channel (-H) of VIRTIS (Cottini et al., 2012, Icarus 217,
561) suggested that a correction of -2 km in low latitudes has to be applied to the absolute values of
the cloud tops. In low and middle latitudes the cloud top defined as the level of unit optical depth at
1.5 micron is thus located at 72+/-1 km. It decreases poleward of +/-50 degrees and reaches 62–68
km in polar regions. The minimum depression of the cloud tops coincides with the hot eye of the
planetary vortex. Cloud top can experience fast variations of about 1 km in tens of hours, while larger
long-term variations of several kilometers have been observed only at high latitudes. UV markings
sometimes correlate with the cloud top altimetry, however the difference between adjacent UV dark
and bright regions never exceeds few hundred meters. Analysis of periodicities in the data similar to
that found in the cloud top winds has been performed.
Abstract Nr. 100
Venus Clouds: Input to VIRA II model from Venus Express and Venera 15 measurements.
Ignatiev Nikolay, IKI-RAS; Zasova Ludmila, IKI-RAS
The original VIRA model of Venus clouds based on measurements from the Pioneer Venus descent
probes and orbiter described mainly cloud particle sizes, properties and their vertical distribution.
Later measurements from Venera-15 and Venus Express permitted more detailed studies of horizontal
and vertical variations. Imaging of Venus in the UV range shows variety of cloud features that include
mottled and streaky clouds in the low latitudes, bright mid-latitude belt and “polar cap” with imbedded
oval polar dipole. Despite this non-uniform picture the location of the upper boundary of the clouds
demonstrates a smooth systematic behavior with the latitudinal trends symmetric with respect to
equator: from 72+/-1 km to 62–68 km in polar regions, with the effective scale height being changed
from 4 to 0.5-2 km. The upper haze demonstrates a similar latitudinal behavior. Venera-15
measurements revealed solar-related structures in the position of cloud tops. The effective average
particle size radius is equal to (1.3+/-0.5) micron at latitudes of 0–70, and 50% larger in the polar
regions. There are evidences that the two modes, micron and submicron, are still both present at
altitudes higher than 70.0 km. UV markings correlate with the cloud top altimetry, however the
difference between adjacent UV dark and bright regions never exceeds few hundred meters. In
contrast to the relatively uniform upper cloud boundary, the total cloud thickness experience strong
variations. Similar to the cloud top latitudinal behavior, the altitude of the cloud base seems also to
THURSDAY, 13 JUNE – PAGE 30 fall between 50 and 75 degrees from 46 to 42 km.
Abstract Nr. 58
High temperature spectroscopy at the Planetary Emissivity Laboratory in support of present
and future Venus missions"
Jorn Helbert, Institute for Planetary Research, DLR; Alessandro Maturilli, Institute for Planetary
Research, DLR; Nils Mueller,Institute for Planetary Research, DLR
The atmosphere of Venus allows observations of the surface only in very narrow spectral windows
around 1 micron. These have been successfully used by the VenusExpress, Galileo and Cassini
spacecrafts as well as by ground-based observers.
For any other planetary body this spectral range would be observed in reflectance. However for Venus
we can obtain useful data only during nighttime using the thermal emission of the surface. So far no
systematic studies have been done on the emissivity of Venus analog materials at high temperatures
in this wavelength range due to the significant technical challenges of such experiments.
At the Planetary Emissivity Laboratory (PEL) we started 6 years ago to extend our laboratory
capabilities to support specifically missions to Venus and Mercury. Both planets exhibit surface
temperatures up to 500°C and this extreme temperature range affects the spectral characteristics of
the surface minerals.
PEL operates a Bruker Vertex 80V, coupled to a custom build planetary simulation chamber. To obtain
measure with a very high signal to noise ratio at 1 micron a liquid nitrogen cooled MCT/InSb detector
is used. PEL uses an innovative approach for heating samples to Venus surface temperatures of
500°C. chamber. The samples are placed in a stainless steel sample cup, which is heated by a 1.5kW
induction system. This approach minimizes heat loss to the chamber.
We have obtained first test measurements of a carbonatite and an ijolite sample clearly indicating
changes of the emissivity signature with temperature. We will report on the experiments and future
plans for the laboratory.
Abstract Nr. 14
Long-lived Emitters in the Atmospheres of the Terrestrial Planets
Slanger, Tom, SRI International
To a large extent, the study of nightglow emissions from the terrestrial planets requires techniques
that target optically metastable emitters. For all three planets, oxygen atoms and molecules are
particularly important, and their excited states typically exhibit long radiative lifetimes. As a
consequence, collisional processes rather than radiation require evaluation. As the principal absorbers
- CO2 for Mars and Venus and O2 for Earth - produce O-atoms, it is not surprising that in the three
cases, knowledge of O/O2 chemistry is crucial. It is interesting to note that the OH molecule is now
known to be important in the three atmospheres [Soret et al., 2012], and that the long history of
understanding OH kinetics and pathways at Earth is now extended to the cases of Venus/Mars.
Techniques developed at SRI International for metastable collisional processes utilize a variety of
techniques, including resonance-enhanced multiphoton ionization (REMPI) [Slanger and Copeland,
2003] and fluorescence [Pejaković et al., 2005], the key being to interrogate the metastable densities
over time scales far shorter than their actual radiative lifetimes.
Additional kinetic information can be derived from ground-based observations of Venus/Mars, where
O/O2 nightglow spectra are discernible, cf. the oxygen green line, the O2 Herzberg II bands, and the
1.27 μ O2 Infrared Atmospheric band.
Soret, L., J.-C. Gerard, G. Piccioni, and P. Drossart,Planet. Space Sci. 73, 387-396, 2012.
Slanger, T.G. and R.A. Copeland,Chem. Rev. 103, 4731-4765, 2003.
Pejaković, D.A., R.A. Copeland, T.G. Slanger, and K.S. Kalogerakis,Chem. Phys. Lett. 405,372-377,
2005.
THURSDAY, 13 JUNE – PAGE 31 Abstract Nr. 131
Experimental and theoretical studies of CO2 infrared absorption continua
J.-M. Hartmann, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA) CNRS (UMR
7583), Universités Paris Est-Créteil et Paris-Diderot 94010 Créteil Cedex, France
Classical Molecular Dynamics Simulations (CMDS) have been carried for gaseous CO2 starting from the
intermolecular potential energy surface. Through classical calculations for a large number of molecules
treated as rigid rotors, the Auto-Correlation Functions (ACF) of the molecule intrinsic dipole and of the
dipole induced by inter-molecular interactions are calculated. The Laplace-Fourier tranforms of these
ACF then directly yield the absorption spectrum, free of any adjustable parameter. Comparisons with
spectra measured at LISA and in other groups are then made in the far and mid infrared regions. They
show that the proposed approach leads to very satisfactory agreement with experiments, both for
collision-induced absorption and for absorption in the far wings of allowed bands. This opens
promising perspectives for a difficult theoretical problem which cannot be solved by purely quantum
approaches. It also opens the route for the prediction of the "continua" in Venus’ atmosphere whose
importance for radiative transfer and remote sensing is well known and will be discussed.
Abstract Nr. 73
Experimental Stability of Tellurium: Implications for the Venusian Radar Anomalies
Kohler, Erika, Arkansas Center for Space and Planetary Sciences, University of Arkansas, Fayetteville,
AR, 72701, USA; Chevrier, Vince, Arkansas Center for Space and Planetary Sciences, University of
Arkansas, Fayetteville, AR, 72701, USA; Gavin, Patricia,Arkansas Center for Space and Planetary
Sciences, University of Arkansas, Fayetteville, AR, 72701, USA; Johnson, Natasha,National
Aeronautics and Space Administration (NASA) Goddard Space Flight Center, Greenbelt, MD, 20771,
USA
Radar mapping of the surface of Venus shows areas of high reflectivity in the Venusian highlands at
altitudes between 2.5-4.75 kilometers. While theoretical studies have been beneficial, the origins
remain unclear and few experimental investigations have been completed. This research
experimentally investigates the stability of tellurium under Venusian conditions with its implications as
a possible source of the radar anomalies.
Stability and reactive experiments on tellurium and mercury sulfide were conducted in the Venus
simulation chamber at NASA Goddard Space Flight Center under average Venusian surface conditions,
and highland conditions (460°C and 90 bar, 380°C and 55 bar respectively). The latter conditions are
the anticipated temperature and pressure at the anomalies altitude. Both compounds were also
heated in a Lindberg tube oven at the University of Arkansas to 460°C and 380°C at ambient
pressure. After each experiment, the samples were weighed and then analyzed using X-Ray Diffraction
(XRD).
Tellurium is unstable under all Venusian conditions and reacts with atmospheric CO2 to form
paratellurite (TeO2). Mercury sulfide vaporizes under all Venusian conditions leaving the mercury to
react with tellurium forming coloradoite (HgTe). The chamber experiments show the same phase
changes for both compounds. However, the Venusian highland conditions are more favorable for the
formation of coloradoite with XRD results showing 3% of the sample was coloradoite at 460°C and
30% forming at 380°C. Coloradoite forms primarily under conditions corelating with the anomaly
altitudes and is a semiconductor, indicating coloradoite could be the source for the Venusian radar
anomalies.
Abstract Nr. 88
Experimental set-up to study optical properties of gases at typically planetary conditions
Stefani Stefania, IAPS-INAF ; Piccioni Giuseppe, IAPS-INAF; Snels Marcel, ISAC-CNR; Adriani
Alberto, IAPS-INAF
THURSDAY, 13 JUNE – PAGE 32 In this work we present an experimental set-up used to study the optical properties of the CO2, the
main constituent of the Venus’s atmosphere, at extreme conditions. This apparatus consists of a
Fourier Transform InfraRed (FT-IT) interferometer and a customized gas cell, designed to support
pressure up to 350 bar and temperature up to 300 ◦ C. Varying the pressure and temperature of the
carbon dioxide according to a real vertical profile, we recreated the same physical conditions of the
Venus deep atmosphere. The CO2 absorption coefficients, recorded with a resolution of 2 cm-1, give us
information about the behavior from an altitude of 50 km down to 16 km. Experimental data have
been compared with synthetic spectra obtained by using a Line Mixing Model (LMM), which take into
account the line mixing effect. The comparison between measured and simulated data leads us to
conclude that the LMM reproduces the data with an integral deviation better than 6% on the full range
explored. The integration of the FT-IR with a multi-pass gas cell, recently acquired, will allow us to
study in more details the complex phenomenon of the Collision-Induced-Absorption (CIA), in addition
to the line mixing and far wings absorption. All the measurements in the lab will significantly improve
the knowledge and the prediction of the radiative transfer calculations, in particular for the Venus
deep atmosphere.
Abstract Nr. 55
Carbon dioxide collision induced absorption in the 1.18 micron atmospheric window of
Venus
Snels Marcel, ISAC/CNR, via del Fosso del Cavaliere, 100, 00133, Rome, Italy; Stefani Stefania, IAPSINAF, via del Fosso del Cavaliere, 100, 00133, Rome, Italy; Piccione Giuseppe, IAPS-INAF, via del
Fosso del Cavaliere, 100, 00133, Rome, Italy; Adriani Alberto, IAPS-INAF, via del Fosso del Cavaliere,
100, 00133, Rome, Italy
The carbon dioxide absorption in the atmospheric windows of Venus is mainly due to collision induced
processes. Whereas absorption close to the band centres of allowed absorption bands is proportional
to the number density, collision induced absorption scales with the square of the density, since twobody forces are involved. These processes can be divided in three categories; collision induced bands,
far wings of allowed bands and continuum absorption.
Collision induced bands are infrared inactive bands which become active due to an collision induced
transition dipole moment. They can be observed as isolated bands or they can be superimposed on
allowed bands. Presently no theoretical model is available to predict the collision induced absorption of
carbon dioxide. The so-called far wings of allowed bands are described in an empirical way, scaling
their intensity with line shape correction factors (chi-factors), which are determined from experimental
spectra. The continuum absorption is a spectrally flat contribution which is taking into account
extreme far wings and any other contributions.
A dedicated cavity ring down spectrometer with an effective optical path of several km has been
developed to measure attenuation of monochromatic light around 1180 nm, through a
CO2 atmosphere at room temperature and at pressures ranging from 0- 40 bar. Preliminary results
showed that this attenuation had a linear variation with density due to Rayleigh scattering and a
quadratic component due to collision induced processes. The wavelength dependence of these collision
induced processes has also been measured from 1179.5 to 1182.7 nm.
THURSDAY, 13 JUNE – PAGE 33 Friday, 14 June Abstract Nr. 115
The influence of surface conditions on global mantle evolution
Moresi, Louis, Monash University; Lenardic, Adrian, Rice University
The ability of the lithosphere to participate in convection is controlled by the mantle stresses and
whether they induce failure in the uppermost few kilometres of the thermal boundary layer. These
stresses can change markedly with moderate changes in the surface temperature because mantle
viscosity is so sensitive to temperature. The effective strength of the lithosphere can also be
influenced by the surface properties such as the presence of water which can produce weaker faults,
for example. We will summarise the approach to understanding the global effects of changes in the
surface conditions.
Abstract Nr. 18
Long term evolution of Venus through Mantle/Atmosphere coupling.
GILLMANN Cedric, ORB (Royal Observatory of Belgium), Bruxelles, Belgium; TACKLEY Paul, ETHZ,
Institute für Geophysik, Zürich, Switzerland
We propose to investigate the evolution of the atmosphere and surface conditions on Venus and how
they are linked with mantle dynamics. Coupling occurs outward due to mantle degassing, and inward
through surface temperature providing boundary conditions for convection processes. Atmospheric
escape is taken into account. During early evolution, hydrodynamic escape is dominant. We use a
model developed to take into account the linked escape of Hydrogen and Oxygen. A significant portion
of the early atmosphere can be removed this way. For later evolution, we focus on non-thermal
escape, as observed by the ASPERA. Post 4 Ga escape is low. The atmosphere is replenished by
volcanic degassing. We use the advanced StagYY code for mantle dynamics and corresponding
volcanic output. We use a gray radiative-convective model for the atmosphere of Venus. By tracking
the evolution of greenhouse gasses in the atmosphere (water and CO2) we follow surface conditions
and temperature over time. We are able to obtain a Venus-like behavior, with resurfacing events. We
are also able to create evolutions leading to present-day conditions. CO2 pressure stays nearly stable
but water pressure is strongly sensitive to volcanic activity, leading to variations in surface
temperatures of up to 200K. We observe a clear negative feedback of the atmosphere on volcanic
activity, as higher surface temperatures lead to a stagnant or episodic lid convection and less melt
production. On the other hand, a lower surface temperature seems to favor mobile lid convection.
Abstract Nr. 60
Thermal evolution of an early magma ocean in interaction with the atmosphere: conditions
for the condensation of a water ocean
Lebrun Thomas, Univ. Paris Sud, Lab IDES CNRS; Massol Hélène, Univ. Paris Sud, Lab IDES CNRS;
Eric Chassefiere, Univ. Paris Sud, Lab IDES CNRS; Davaille Anne, Univ. Paris Sud, Lab FAST CNRS;
Marcq Emmanuel, LATMOS, CNRS; Sarda Philippe, Univ. Paris Sud, Lab IDES CNRS; Leblanc
François, Univ. Paris 6, LATMOS, CNRS; Brandeis Geneviève, IPGP, CNRS
The thermal evolution of magma oceans produced by collision with giant impactors late in accretion is
expected to depend on the composition and structure of the atmosphere through the greenhouse
effect of CO2 and H2O released from the magma during its crystallization. In order to constrain the
various cooling timescales of the system, we developed a 1D parameterized convection model of a
magma ocean coupled with a 1D radiative convective model of the atmosphere. We conducted a
FRIDAY, 14 JUNE – PAGE 34 parametric study and described the influences of the initial volatile inventories, the initial depth of the
magma ocean and the Sun-planet distance. Our results suggest that a steam atmosphere delays the
end of the magma ocean phase by typically 1 Myr. Water vapor condenses to an ocean after 0.1 Myr,
1.5 Myr and 10 Myr for, respectively, Mars, Earth and Venus. This time would be virtually infinite for
an Earth-sized planet located at less than 0.66 AU from the Sun. Using a more accurate calculation of
opacities, we show that Venus is much closer to this threshold distance than in previous models. So
there are conditions such as no water ocean is formed on Venus. Moreover, for Mars and Earth, water
ocean formation time scales are shorter than typical time gaps between major impacts. This implies
that successive water oceans may have developed during accretion, making easier the loss of their
atmospheres by impact erosion. On the other hand, Venus could have remained in the magma ocean
stage for most of its accretion.
Abstract Nr. 117
Early evolution of telluric atmospheres in the magma ocean stage
Marcq, Emmanuel, LATMOS / Univ. de Versailles Saint-Quentin; Lebrun, Thomas, IDES / Univ. Paris
11; Massol, Hélène, IDES / Univ. Paris 11; Chassefière, Éric, IDES; Leblanc, François, LATMOS
In order to investigate the evolution of telluric planets, we have to understand the possible outcome of
the very early stages, when interactions between the primitive atmosphere and the solid planet are
much more pervasive than at later stages. A joint work between LATMOS (atmosphere) and IDES
(interior) has thus been led by H. Massol, and have already led to two publications (E. Marcq, 2012 ;
Lebrun et al., 2013). This talk will focus on the behaviour of the atmosphere, modeled following
Kasing et al. (1988) work with minimal adjustement of the thermal profile and calculations of the
outgoing IR (0-104 cm-1) flux only using k-correlated and continuum opacities. The main results are :
Above a certain threshold surface temperature dependent on the total amount of CO2 and H2O, the
blanketing effect becomes inefficient (i.e., even the upper radiative part of the atmosphere becomes hot
enough to cool efficiently) and rapid thermal cooling may occur ;
Below this threshold, the thermal flux becomes nearly constant and independent on the surface
temperature. This behavior was already known (Nakajima-Kombayashi-Ingersoll limit), but the value we
find for this flux (about 200 W/m2) is much lower than previous estimates.
Future work will imply a redesign of the atmospheric model and a incorporating atmospheric escape
processes so that the simulations may be extended far after a few million years at it is presently the
case.
Abstract Nr. 38
Volcanism and Climate on Venus: An Updated Model
Taylor, Fred, Oxford University
An attempt is made to represent the climate history of Venus by a single time-dependent model. This
aims to incorporate all known facts and data, interpolated with simple physical models, analogies with
Earth, and considered assumptions. In each epoch, a key factor is the level of volcanic emission of
different gases into the atmosphere and this must be estimated from the evidence. The case is
presented for the overall activity being similar, or somewhat higher, than Earth at the present time,
and 5 to 100 times higher in the fairly recent past. Future Venus will have little or no volcanic
emission, like present-day Mars, and the climate may relax to the tropical Earth-like state predicted by
Arrhenius and others before the space era.
Abstract Nr. 133
New calculations of the runaway greenhouse limit: bad news for early Venus and future
Earth
Goldblatt C., University of Victoria, Canada
FRIDAY, 14 JUNE – PAGE 35 We all know that Venus went through a runaway greenhouse in the past, with hydrogen escape from
the resultant steam atmosphere giving rise to the observed D/H enrichment. In this talk, I will review
the physics of the runaway greenhouse in terms on limits on outgoing thermal radiation and on the
absorption of solar radiation, present new calculations of these limits and discuss the implications for
Venus and Earth.
Planetary atmospheres must be in long-term radiation balance, with solar radiation absorbed matched
by thermal radiation emitted. For hot moist atmospheres, however, there is an upper limit on the
thermal emission which is decoupled from the surface temperature. If net absorbed solar radiation
exceeds this limit the planet will heat uncontrollably, the so-called ``runaway greenhouse''.
We have calculated the clear-sky radiation limits at line-by-line spectral resolution for the first time.
The thermal radiation limit is lower than previously reported (282Wm-2 rather than 310Wm-2) and
much more solar radiation would be absorbed (294Wm-2 rather than 222Wm-2, using the Solar
constant at Earth as a reference).
For Earth, the implication is that a runaway greenhouse steam atmosphere may be a stable state
under the present insolation, contrary to previous results. Avoiding a runaway greenhouse under the
present solar constant requires that the atmosphere is subsaturated with water, and that cloud albedo
forcing exceeds cloud greenhouse forcing. For Venus, these results make an early habitable period
more difficult to justify. Possible saviours for early Venus could be a dense nitrogen atmosphere (more
Rayleigh scattering would mean less sunlight woruld be absorbed) or more low cloud.
Abstract Nr. 79
The origin and early evolution of Venus, Earth and Mars: Clues from bulk properties and the
abundances and isotopic ratios of noble and light gases
Baines, K. H., SSEC, University of Wisconsin - Madison; Atreya, S. K., University of Michigan; Bullock,
M. A., Southwest Research Institute; Grinspoon, D. H., Denver Museum of Natire and Science;
Mahaffy, P. R., NASA Goddard Space Flight Center; Russell, C. T. , University of California, Los
Angeles; Schubert, G. , University of California, Los Angeles; Zahnle, K. J., NASA/Ames Research
Center
Based on similar bulk compositions, Venus, Earth and Mars likely formed in the same realm of the
solar nebula. However, variations in the noble gas content of each – particularly in the isotopic ratios
of xenon, krypton and neon, can distinguish whether the trio of terrestrial planets that bear significant
atmospheres had major contributions to their makeup contributed by (1) asteroids, (2) the outer solar
system via comets, (3) inner-solar-system objects that were markedly processed by the solar wind,
and/or (4) erosional processes, such as the EUV and charged-particle precipitation from the bright,
early Sun or from large impacts during the late stages of accretion. While the entire inventory of
noble gases is known accurately for Earth and Mars,.our knowledge of the inventory for Venus is
severely lacking. Indeed, there are no measurements for the nine isotopes of xenon, the
measurements of the krypton abundance range over more than an order of magnitude, and many of
the other noble gas isotopic abundances are known to just the ~ 10-20 % level. In this talk, we
discuss specific origin and early evolutionary scenarios for the planets of the inner solar system based
on their bulk properties (e.g., size, composition, magnetic fields, rotation rate, and satellites) and on
what is known and unknown about the inventories of their noble gases and light isotopes, highlighting
hypotheses that could be confirmed or rejected through the acquisition of more precise data,
especially for Venus.
Abstract Nr. 43
Present status of AKATSUKI
Nakamura Masato, ISAS; AKATSUKI Project team, ISAS
Japanese Venus Climate Orbiter 'AKATSUKI' (PLANET-C) was successfully launched at 06:58:22JST on
May 21, by H-IIA F17. The malfunction, which happened during the Venus Orbit Insertion (VOI) on 7
FRIDAY, 14 JUNE – PAGE 36 Dec, 2010 is as follows. Orbital maneuver engine (OME) was fired 08:49 JST on Dec. 7. 1min. after
firing the spacecraft went into the occultation region and we had no telemetry, but we expected to
continuous firing for 12min. Recording on the spacecraft told us later that, unfortunately the firing
continued just 152sec. and stopped. The reason of the malfunction of the OME was the blocking of
check valve on the gas pressure line to push the fuel to the engine. We failed to make the spacecraft
the Venus orbiter, and it is rotating the sun with the orbital period of 203 days.
Most of the fuel still remains, but the OME was found to be broken. We decided to use only RCS for
orbit maneuver and 3 minor maneuvers in November 2012 were successfully done so that AKATSUKI
will meet Venus in late 2015. We are considering several scenarios only using RCS for VOI. In the
presentation we will show the possible orbits and how we put the spacecraft into those orbits. They
have higher apoapsis than we expected in the initial design, but they are still westward and equatorial
that is ideal to reveal the mechanism of the super-rotation of the atmosphere, and we think we will be
able to achieve the scientific goals which we have been proposing.
Abstract Nr. 123
Future Exploration of Venus
Limaye, University of Wisconsin; International Venus Exploration Working Group, COSPAR
By the end 2015, Venus Express will have observed Venus for nearly ten years, just short of one solar
cycle, or nearly fifteen Venus days. A number of significant discoveries have been made and a lot of
new questions have been raised by these observations. The knowledge gained from these results is
helping refine ideas for future exploration of Venus for the questions that have not been addressed by
Venus Express, others that can be refined or narrowed and new ones that require new
measurements. These will also be helped by the assessment of the Venus atmospheric observations
available to date through the efforts of the international teams that are proposing to the International
Space Science Institute to discuss the thermal structure, sulfur dioxide abundance and
clouds/aerosols.
The Comparative Climatology of Terrestrial Planets Conference sponsored by all four Divisions within
NASA's Science Mission Directorate considered Venus as a natural laboratory for better understanding
of climates of extra-solar planets and also our own in the context of the continuing discussion of solar
and cosmic ray influences on the climate that encourage long term monitoring of Venus to refute or
confirm such connections.
The opportunities for future exploration missions to Venus are available through the competed
programs such as ESA's Cosmic Vision Program for M and L class missions and through NASA's
Discovery and New Frontiers Programs. the US National Academies Decadal Survey of Planetary
Science has recommended the Venus Climate Mission to be carried out during 2013-2022. The
constrained budgets predicted in the near future for NASA however make the prospects for launch of
this mission unpredictable at present and can improve only through coordinated international efforts.
Other agencies appear to have cintinuing interest in exploring Venus, and we await the insertion of
JAXA's Akatsuki mission into orbit in Venus in 2015 or 2016.
The Venus Exploration Analysis Group (VEXAG) has initiated a Roadmap activity to focus some
attention on the future exploration efforts and also provides opportunities for international dialog
through the International Venus Exploration Topical Group. At the last COSPAR meeting in July 2012
a Venus International Exploration Working Group was formed.
Continuing inter agency dialog is critical to the success of a coordinated strategy to explore Venus as a
system as considered by the decadal survey. Small missions can answer focused questions about
Venus, while larger, Cooperative, international missions are more able to address a broader range of
science.
Abstract Nr. 12
Beyond Venus Express : clues for future infrared remote sensing experiments
FRIDAY, 14 JUNE – PAGE 37 Pierre Drossart, LESIA, Observatoire de Paris
Along the Venus Express nominal and extended mission, infrared remote sensing instruments (VIRTIS,
SPICAV, and VMC) have provided numerous parameters of the Venus surface and atmosphere,
expanding by a large factor our knowledge of the planet. To go beyond, there is no doubt about the
necessity for a future mission to access to the atmosphere and surface through in situ sounding by
landers or balloon experiments, but there are still many aspects accessible to remote sensing which
would provide first rank scientific investigations. Among still almost unexplored domains are the
studies of the Venus seismology, on the one hand, and of the upper mesospheric wave activity on the
other hand. A comparison with the first clues obtained from VIRTIS on board Venus Express on gravity
waves (Garcia et al, JGR, 2010) observed in the upper atmosphere from CO2 non-LTE emissions will
give access to science specifications for an instrument devoted to upper atmosphere wave activity
measurements. Some of the wave activity can be produced by a coupling between Venus seismic
activity and wave propagation in the ionosphere, as exemplified by Earth tsunami detection from
ionospheric disturbances (e.g. Makela et al, GRL, 2011), and threshold of detection depending on
instrument sensitivity will be discussed.
Abstract Nr. 39
Venus III Book Status
Taylor, Fred, Oxford University
As a contribution to the session on 'Venus International Reference Atmosphere, VIRA II', it is proposed
to present an update on the status of the proposed 'Venus III' book that has been discussed at several
earlier Venus-oriented meetings (eg Madison 2010) or sessions at larger meetings (eg DPS 2010).
There has been little forward progress recently,and colleagues are invited to consider whether the idea
still has validity, and if so what might be a reasonable schedule, alongside or after VIRA II.
FRIDAY, 14 JUNE – PAGE 38 POSTER CONTRIBUTIONS Poster Sessions will take place on Monday afternoon (10 June) and Wednesday afternoon
(12 April) at the Polifunzionale Hall.
Poster Size
Each poster board has a dimension of 100 cm (width) x 200 cm (height). Posters, portrait
orientation, must not exceed 100 cm on width and 120 cm on height to fit the assigned
space and be easily readable.
All poster contributions will have a number and an assigned space on poster boards.
Mounting the Posters
Posters of group 1 can be mounted Monday afternoon and removed on Wednesday
afternoon. Posters of group 2 can be mounted on Wednesday afternoon and may be
removed on Friday morning, before the end of the workshop.
All necessary material for poster display (pins, etc) will be provided on site.
POSTER CONTRIBUTION Group 1 poster – Mon‐Wed Abstract Nr. 92
Errors and Artifacts in the Magellan Imagery of the Surface of Venus
C G Cochrane, Imperial College; R C Ghail, Imperial College
NASA’s plan for Magellan did not include a ground truth campaign or stereo imaging. After 2 Cycles
of imaging covering 98% of the surface of Venus, and following a stereo trial, NASA did approve a
third Cycle for stereo mapping. Cycle 3 coverage was limited by Tracking Station availability and
radar performance, and ended on radar failure. There are no published papers on the systematic
errors in the Magellan stereo data. Here, 62 Digital Elevation Model (DEM)s are used to characterise
these horizontal plane ground position errors and show them to be within the range of 118 to 128 m.
This range is rather larger than some previous authors have estimated but comparable to the 100 m
positioning accuracy required for InSAR imaging during the EnVision Mission. The paper goes on to
show how mapping from the Magellan might be used for EnVision navigation, the importance of
characterising EnVision’s imaging performance by terrestrial ground truth comparison, and how the
Magellan DEMs illustrate the types of artefact to be avoided by EnVision.
Abstract Nr. 65
Stereo-Derived Topography To Aid Emissivity Estimates at Tesserae on Venus
Nunes, Jet Propulsion Lab, NASA/Caltech; Mitchell, Jet Propulsion Lab, NASA/Caltech; Hensley, Jet
Propulsion Lab, NASA/Caltech; Mueller, German Space Agency (DLR); Smrekar, Jet Propulsion Lab,
NASA/Caltech
Though dominated by plains volcanism and thick-lid lithosphere, earlier periods of the recorded
geologic history of Venus display, in the form of tesserae, considerable lateral deformation, thin
lithosphere, and thick crust. Tessera formation is not understood; models include mantle-crust
coupling above downwellings, volcanic underplating, and even compositionally distinct crust. Surface
emissivity for the southern hemisphere was derived from surface brightness acquired at 1.18 µm by
the VIRTIS instrument on Venus Express. Large tessera terrains seen by VIRITS (e.g., Alpha Regio)
have low emissivity signatures, possibly indicating relatively high silica [Mueller et al., 2008]. Such
more evolved composition generally indicates lower solidus, lower mechanical strength, and may
hold significant implications for crustal evolution.
To obtain emissivity values from VIRTIS data it is necessary to correct for terrain elevation, but
Magellan altimetry is neither accurate nor spatially resolved for properly correcting for elevation in
tesserae. We seek to lessen this limitation by creating high resolution DEM’s from stereo coverage of
Magellan SAR imaging.
Our technique [Hensley and Shaffer,1994] uses a hierarchical scheme that applies a 2-D normalized
correlation function to determine offsets between two images with formal error calculation, which is
of crucial importance in constraining emissivity values. Our preliminary results with lateral resolution
of 600 m and vertical resolutions of less than 100 m, similar toHowington-Kraus et al.[2006], are a
marked improvement over Magellan altimetry. We are currently processing data for tessera near
Alpha Regio and will use the resulting DTM and uncertainties to constrain tessera emissivity.
Abstract Nr. 69
A global comparison between VeRa radio science observations of the Venus dayside
ionosphere and the IonA model
Peter, Kerstin, Rheinisches Institut für Umweltforschung, Abt. Planetenforschung, Cologne,
Germany; Pätzold, Martin,Rheinisches Institut für Umweltforschung, Abt. Planetenforschung,
Cologne, Germany; Tellmann, Silvia, Rheinisches Institut für Umweltforschung, Abt.
GROUP 1 POSTER – MON‐WED – PAGE 39 Planetenforschung, Cologne, Germany; Häusler, Bernd, Institut für Raumfahrttechnik, Universität
der Bundeswehr München, Munich, Germany; Bird, Michael K., Argelander-Institut für Astronomie,
Bonn, Germany
The radio science experiment VeRa on Venus Express has been sounding the atmosphere and
ionosphere of Venus since 2006. To date, more than 400 complete vertical electron density profiles
have been recorded for a large variety of observational parameters (solar zenith angle, latitude, local
time, season, solar activity cycle). IonA (Ionization in Atmospheres), a fast and flexible software
package for the 1D photochemical modeling of lower planetary ionospheres, is examined here for the
ionosphere of Venus. The background neutral atmosphere for Venus is taken from the VenusGRAM
model, which interpolates temperature/density profiles of the most important atmospheric species as
a function of planetary latitude, solar local time and zenith angle from the VIRA database. The solar
radiation for the IonA model is taken from the Solar2000 program. These underlying databases allow
the direct modeling of the Venus ionosphere for the given VeRa observational parameters and
therefore a direct comparison between the observation and the IonA model. Although the general
structure of the lower Venus ionosphere is reproduced by IonA, the inadequate VIRA neutral
atmosphere model induces significant differences between observation and IonA. The actually
encountered neutral atmosphere at ionospheric altitudes is either warmer or of higher density (or
both) than the VIRA predictions.
Abstract Nr. 07
ULF and ELF Electromagnetic Waves in the Venus Ionosphere: Separating Atmospheric and
Magnetosheath Sources
Russell, Christopher T., UCLA; Hart, Richard A., UCLA; Leinweber, Hannes, UCLA; Wei,
Hanying, UCLA; Strangeway, Robert J., UCLA; Zhang, Tielong, Austrian Academy of Sciences
The Venus Express magnetometer has two tri-axial sensors separated by a one-meter boom that
allows the separation of spacecraft and ambient contributions to the observed spectrum. In the
ionosphere two distinct wave types are seen: circularly-polarized right-handed waves and linearlypolarized largely compressional ULF waves. The first type is detected over the entire spectral band.
The latter waves are seen usually at lowest frequencies below about 10 Hz, but when the ambient
field strength is high (~50 nT), the linearly polarized waves can be detected over the entire
frequency band of the magnetometer. The behavior of these "ULF" linearly polarized waves is
consistent with their propagation across the magnetic field from below or above the spacecraft. The
behavior of the ELF circularly polarized waves is consistent with their propagation along the magnetic
field from a nearby source (~300 to 600 km away). We examine the occurrence of both wave modes
at low altitudes and high, and conclude that the circularly polarized waves are produced below the
spacecraft in the atmosphere and that the linearly polarized waves are produced in the solar wind
interaction region at high altitudes.
Abstract Nr. 94
Solar wind precipitation on Venus
Stenberg Gabriella, Swedish institute of space physics; Futaana Yoshifumi, Swedish institute of
space physics; Barabash Stas,
Solar wind ions are known to precipitate onto the atmosphere of Mars. The large gyroradii of hot
particles in the magnetosheath compared to the size of the induced magnetosphere/magnetic barrier
make it possible for the ions to gyrate through the barrier. Venus interacts with the solar wind in a
similar way and an induced magnetosphere is formed around the planet. However, the scale-sizes
are different and precipitation of solar ions onto the atmosphere of Venus is less frequently
occurring. We use ion data from ASPERA-4 on Venus Express to investigate how often precipitation
of protons and alpha-particles occurs on Venus. With a statistical approach we also estimate the net
inflow of solar wind ions onto the ionosphere of Venus. We highlight the differences between solar
wind ion precipitation at Mars and Venus and suggest possible explanations for the observed
differences.
GROUP 1 POSTER – MON‐WED – PAGE 40 Abstract Nr. 108
A new dawn-dusk asymmetry in the photoelectron flux of Venus’s Ionosphere
Molaverdikhani Karan, Laboratory for Atmospheric and Space Physics, University of Colorado,
Boulder, Colorado, USA; Brain David A., Laboratory for Atmospheric and Space Physics, University of
Colorado, Boulder, Colorado, USA; Mcenulty Tess,Laboratory for Atmospheric and Space Physics,
University of Colorado, Boulder, Colorado, USA
Photoelectrons are excellent tracers of ionospheric plasma. Produced via photoionization of
atmospheric neutral particles by solar EUV and X-ray radiation, photoelectrons remain tightly bound
to magnetic field lines passing through their location of origin. Spacecraft measurements of
photoelectrons therefore allow us to infer which regions of space around a planet are magnetically
connected to the ionosphere.
We have developed and tested an automatic algorithm to detect the presence of photoelectrons in
ASPERA-4 ELS measurements. The algorithm identifies ionospheric photoelectron distributions as a
localized peak between 20 to 30 eV in electron energy spectrum. We have applied the filter to six
years of Venus Express data to determine the distribution and variability of photoelectrons near the
planet, with special emphasis on altitudes <1000 km .
We present the characteristics of the measured photoelectron energy distributions, and show how
they vary temporally and spatially at Venus. We have identified a new dawn-dusk asymmetry in the
ionosphere. Photoelectron flux is enhanced on the dawn side at solar minimum below 250 km and
enhanced on the dusk side to higher altitudes as solar activity increases. We find no correlation
between these flux enhancements and Interplanetary Magnetic Field strength or direction. We
present some plausible ideas to explain the newly found asymmetry based on the asymmetry of
neutrals near Venus and plasma transport mechanisms.
Abstract Nr. 78
Limb fitting and cloud tracking for the study of the Venus atmosphere
OGOHARA Kazunori, Japan Aerospace Exploration Agency; KASHIMURA Hiroki, Japan Aerospace
Exploration Agency; KOUYAMA Toru, National Institute of Advanced Industrial Science and
Technology; SATO Naoki, Tokyo Gakugei University; TAKAGI Masahiro, Faculty of Science, Kyoto
Sangyo University; IMAMURA Takeshi, Japan Aerospace Exploration Agency; HORINOUCHI
Takeshi, Hokkaido University
We have developed the new image processing system for the study of the planetary atmosphere. We
have successfully corrected attitude information of the satellite, which has a serious effect on the
accuracy of cloud motion vectors (CMVs). We can transform accurately a Venus image into a
longitude-latitude map of brightness using the "limb fitting" technique and can obtain CMVs by
tracking cloud features on such longitude-latitude maps of brightness. The attitude correction by
limb fitting has so large impacts on CMVs that the direction of the meridional component of CMVs in
low latitudes is completely changed. We have already obtained longitude-latitude maps of brightness
and CMVs as NetCDF files using our system from all VMC images (UV, NIR1, NIR2 and VIS) that
have been released to the public (ftp://psa.esac.esa.int/pub/mirror/VENUS-EXPRESS/VMC/). We will
be able to progress the study of the Venus atmospheric dynamics using such brightness and CMV
datasets.
Abstract Nr. 119
Mesospheric Temperature at Terminator using SDO/HMI Aureole Photometry, DST/FIRS
CO2 absorption spectroscopy and comparison with Venus Express
Widemann Thomas, LESIA - UMR CNRS 8109, Observatoire de Paris-Meudon - Place Jules-Janssen,
92190 Meudon cedex; Tanga Paolo, Laboratoire LAGRANGE – UMR CNRS 7293, Observatoire de la
Côte d’Azur, Université de Nice Sophia Antipolis BP4229 – 06304 Nice Cedex 4 – France ; Vandaele
GROUP 1 POSTER – MON‐WED – PAGE 41 Ann Carine , Belgian Institute for Space Aeronomy, Brussels, Belgium; Wilquet Valérie, Belgian
Institute for Space Aeronomy, Brussels, Belgium; Mahieux Arnaud, Belgian Institute for Space
Aeronomy, Brussels, Belgium; Jaeggli Sarah A. , Montana State University, MT; Reardon
Kevin, National Solar Observatory, Tucson, AZ; Penn Matthew J., National Solar Observatory,
Tucson, AZ; Pasachoff Jay M., Williams College-Hopkins Observatory, Williamstown, MA
We report on Solar Dynamical Observatory/HMI photometric observations and Dunn Solar
Telescope/FIRS Adaptative Optics spectropolarimetric observations of CO2 absorption at 1.57 and
1.61um during the June 5-6 transit of Venus. Close to ingress and egress phases, the fraction of
Venus disk projected outside the solar photosphere is outlined by an irregular thin arc of light called
the “aureole”. We have shown that the the aureole photometry reflects the local density scale height
and the altitude of the refracting layer (Tanga et al. 2012). SDO measurements are in agreement
with the VEx/SOIR temperatures obtained during orbit 2238 at evening terminator during solar
ingress (46.75N - LST = 6.075PM) and solar egress (31.30N - LST = 6.047PM) as seen from the
orbiter. The polar aureole, significantly brighter than the mid-latitude aureole due to the larger scale
height of the polar mesosphere, appears consistently offset toward morning terminator by about 15
deg. latitude near 75N. This result reflects local latitudinal structure in the polar mesosphere, both in
temperature and aerosol altitude distribution. The Facility IR Spectropolarimeter is a multi-slit
spectropolarimeter designed for the Dunn Solar Telescope at the National Solar Observatory on
Sacramento Peak in New Mexico to study magnetism on the solar surface. Sun-subtracted Venus
limb observations show intensity distribution of vibrational CO2 bands 221 2nu + 2nu2 + nu3 at
1.571um and 141 nu1 + 4nu2 + nu3 à 1.606um. Comparison with ESA / Venus Express / SOIR
mean profiles (Mahieux et al., 2012) and temperature modeling at terminator will be discussed at
the meeting.
Mahieux et al., J. Geophys. Res. , VOL. 117, E07001, doi:10.1029/2012JE004058 (2012)
Tanga et al., Icarus 218, 207-219 (2012)
Abstract Nr. 27
Vertical structure of the Venus vortex
Ando Hiroki, ISAS/JAXA; Imamura Takeshi, ISAS/JAXA; Bernd Häusler, Universität der Bundeswehr
München; Martin Pätzold,Universität zu Köln
The existence of the Venus vortex which orbits the polar with the period of ~3 days has been know
from the Pioneer Venus mission, and there are some theoretical studies which explain how this
phenomena are maintained. However, the definitive dynamical model has not been constructed yet
because vertical structure of the Venus vortex is not clearly known.
In this study, we used the vertical temperature profiles obtained from January 20th to 26th 2008
and examined the deviations from the mean temperature field within the altitude range of 55-70 km.
As a result, we found the quasi-periodic fluctuations with the period of ~3.2 days at each altitude.
Then, the phases and amplitudes of these fluctuations are calculated to find that the structure of the
vortex seems to be barotropic.
Abstract Nr. 30
Temperature variation of the cloud top of Venus obtained by photometry observation by
LIR onboard Akatsuki
Fukuhara Tetsuya, Hokkaido Univ.; Kouyama Toru, AIST; Imamura Takeshi, ISAS/JAXA; Futaguchi
Masahiko, Rikkyo Univ.; Shima Yuna, Hokkaido Univ.; Taguchi Makoto, Rikkyo Univ.; LIR team,
Although Akatsuki failed to enter the Venus’ orbit, the Longwave Infrared Camera (LIR) successfully
acquired 52 photometry data of day-side Venus between February and March 2011 at a distance of
1.2-1.7×107 km. The spatial resolution of LIR and an apparent diameter of Venus being almost
equivalent, Venus' disk in the image extends to several pixels that include both Venus and the
background radiation. All brightness pixels that included Venus were summarized and background
radiations were removed from them to estimate a Venus' original brightness components. They have
been converted to the brightness temperatures by using calibration data acquired in the laboratory
GROUP 1 POSTER – MON‐WED – PAGE 42 before the launch, and variation during the observation has been obtained. These discrete data
having heterogenous data gaps, the Lomb-Scargle periodgram, which is better suitable than Fast
Fourier Transform, has been applied to obtain a power spectrum density. The result shows spectrum
peaks at 5-day and 8-day period. The 5-day period may be caused by the super rotation, and the 8day period may be a planetary-scale wave that has the phase velocity of ~50 m/s.
Abstract Nr. 84
Gravity waves in Venus mesosphere observed by the Venus Monitoring Camera on board
Venus Express
Piccialli Arianna, LATMOS-UVSQ, Guyancourt,France
High resolution images of Venus Northern hemisphere obtained with the Venus Monitoring Camera
(VMC/VEx) allow studying small-scale dynamical phenomena at the cloud tops (~66 km altitude) and
mesoscale features like wave trains. A systematic visual search of these waves was performed; more
than 1500 orbits were analyzed and wave patterns were observed in about 300 images. Four types
of waves were identified in VMC images on the base of their morphology: long, medium, short and
irregular waves. With the aim to characterize the wave types and their possible source of excitation,
we retrieved wave properties such as location (latitude and longitude), local time, solar zenith angle,
packet length and width, orientation, and wavelength of each wave. Thelong type wavesappear as
long and narrow straight features extending more than a few hundreds kilometers and with
wavelengths between 7 and 17 km.Medium type wavesexhibit irregular wavefronts extending more
than 100 km and with wavelengths in the range 8 – 21 km.Short wave packetshave a width of
several tens of kilometers and extend to few hundreds kilometers and are characterized by smaller
wavelengths (3 – 16 km).Irregular wave fieldsappear to be the result of wave breaking or wave
interference. The waves are often identified in all VMC filters and are mostly found at high latitudes
(60–80ºN) and seem to be concentrated above Ishtar Terra, a continental size highland that includes
the highest mountain belts of the planet.
Abstract Nr. 40
Polar Vortex: a common element of the Earth and Venus.
Prof. Lucia Marinangeli, Dr. Arturo Cannito, DISPUTer - Universita' G. d'Annunzio - Chieti
Polar vortices are common structures and can be found at the poles of any planet with an
atmosphere.Earth and Venus have a persistent, large-scale cyclone located near one or both of a
planet's geographical poles, although with different origins.
On Earth, the polar vortices are located in the middle and upper troposphere and the stratosphere.
They surround the polar highs and lie in the wake of the polar front. These cold-core low-pressure
areas strengthen in the winter and weaken in the summer. ]They usually span 1000–2000 kilometers
in which the air is circulating in a counter-clockwise manner in the northern hemisphere and
clockwise manner in the southern hemisphere. The reason for the rotation is the same as any other
cyclone, the Coriolis effect.
Instead, on Venus where the Coriolis force is negligible, the polar vortices are due to a complex
atmospheric patterns. Images from (VIRTIS) instrument have shown that the Venus’ polar vortex
change continuously internal structure and position with a period of 5 to 10 Earth days. This
situation could be related to what happens at the Earth’s South Pole over Antarctica to understand
climate evolutions and change of planets with atmosphere.
On the Earth, synoptic perturbations of the Antarctic polar vortex such as distortion or displacement
away from the geographic pole, might influence drought in Australia.
We explore possible analogies between the terrestrial and venusian polar vortex which may help to
explain why arid climatic conditions are getting worst in Southern Australia and if there is a direct
link between polar vortex and weather conditions elsewhere.
Prof. Lucia Marinangeli
Dr. Arturo Cannito
GROUP 1 POSTER – MON‐WED – PAGE 43 Abstract Nr. 01
Towards a general classification of atmospheric waves on Venus
Peralta J., IAA/CSIC (Spain); Luz D., OAL/CAAUL (Portugal); Imamura T., JAXA (Japan); Piccialli
A., LATMOS-UVSQ (France)
The atmospheric superrotation of Venus goes on being a puzzling phenomenon in the Solar system
and is still considered an open problem in geophysical fluid dynamics. A general agreement exists
among numerous works concerning the main role that atmospheric waves should have in the
generation and maintenance of the superrotation, although most of them try to study the impact of
the waves with complex GCMs or using adapted terrestrial dispersion relations by considering frames
fixed to the winds. In this work we derive, for the first time, the dispersion relations for a wide
variety of possible atmospheric waves in Venus. These dispersion relations are analytically extracted
from the primitive equations under reasonable assumptions valid for the cloud region of Venus and
above, and the effect of the meridional shear of the wind and the vertical variation of the static
stability are also considered. Noteworthy similarities are found for small-scale and mesoscale waves
in comparison with the Earth; the global-scale waves, however, exhibit significant differences. These
dispersion relations allow building dispersion graphs for different regions of the atmosphere of Venus
and classifying a number of waves identified in Venus Express remote sensing data. Finally, a new
type of global-scale wave whose restoration force is the centrifugal force is predicted by our
equations, which has been confirmed by observations.
Abstract Nr. 17
Simulation of Venus’ polar vortex in the presence of diurnal thermal tide
Yamamoto, Masaru, RIAM, Kyushu University
Dynamical impacts of diurnal thermal tide on Venus' polar vortex have not been fully understood,
though polar diurnal tides were observed in the Pioneer Venus IR observation. In this study, polar
vortex in the presence of thermal tide is investigated using a Venusian middle atmosphere general
circulation model (Yamamoto and Takahashi 2012). At 70 km, warm polar region is formed by the
thermal-wind relation associated with a high latitude jet in the cloud layer, and cold collar and hot
oval (monopole) near the pole are enhanced by the polar diurnal tide. In such a zonally non-uniform
basic field (of zonal mean with slowly traveling diurnal tide), unstable vortices with higher zonal
wavenumbers form hot dipole and tripole. A hot dipole appears and breaks up into a tripole, when
divergent eddies with zonal wavenumbers 2 and 4 are predominant in the polar hot oval region. Hot
(cold) anomalies correspond to convergences (divergences) of horizontal wind, and are by 90 deg
out of phase with the eddy vorticity component. Because the vortical eddies transport heat toward
the cold region, the polar vortices are mainly formed by baroclinic waves in the presence of polar
diurnal tide. The present work suggests that both thermal tide and baroclinic wave are dynamically
important in the formation of the Venusian polar vortices.
Abstract Nr. 85
Venus cloud tops winds with ground-based Doppler velocimetry and comparison with
cloud tracking method
Machado, Pedro, ) LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules
Janssen, 92195 Meudon cedex, France.; Widemann, Thomas, ) LESIA, Observatoire de Paris, CNRS,
UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon cedex, France.; Luz,
David, CAAUL-Centro de Astronomia e Astrofísica da Universidade de Lisboa, Portugal, ; Peralta,
Javier, Instituto de Astrofísica de Andalucía (CSIC), Granada, Spain.
We present new results based on Doppler wind velocimetry obtained with the 3.60 m CanadaFrance-Hawaii telescope (CFHT) and the Visible Spectrograph ESPaDOnS in 2009 and 2011. These
observations consisted of high-resolution spectra of Fraunhofer lines in the visible range (0.37–1.05
mm) to measure the winds at cloud tops using the Doppler shift of solar radiation scattered by cloud
GROUP 1 POSTER – MON‐WED – PAGE 44 top particles in the observer’s direction (Widemann et al., 2007, 2008). The complete optical
spectrum was collected over 40 spectral orders, at a resolution of about 80000. We measured the
winds using Doppler shifted solar lines and compare with our measurements with VLT/UVES
(Machado et al., 2012) and with synchronized coordinated observations by the Venus Monitoring
Camera (VMC) and the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instruments
from Venus Express (ESA). The observations included various points of the dayside hemisphere at a
phase angle of 67º, between +10° and -60° latitude, in steps of 10°, and from +70° to -12°
longitude in steps of 12°.
Doppler retrievals are in general good agreement with measurements based on cloud tracking, as
was the case in previous investigations. Our analysis technique allows characterizing the latitudinal
zonal wind profile and its variability, using repeated acquisitions extending over several days, as well
as the effect of large-scale planetary waves in the maintenance of superrotation. To provide the best
description of the wind field observed, we compare our results to a series of wind models. New
constrains on detection of a meridional circulation will be assessed.
Abstract Nr. 19
The time evolution of O2(a1Δ) individual observations acquired by VIRTIS-M on board
Venus Express
Soret Lauriane, ULg - LPAP; Gérard Jean-Claude, ULg - LPAP; Piccioni Giuseppe, IAPS - INAF;
Drossart Pierre, Observatoire de Paris Meudon - LESIA
The O2(a1Δ) nightglow emission at 1.27 µm may be used as a tracer of the Venus upper
mesosphere dynamics. This emission has been observed with VIRTIS-M-IR on board Venus Express.
Previous studies showed that the emission maximum is statistically located close to the antisolar
point at ~96 km. This airglow results from the production of oxygen atoms on the Venus dayside by
photodissociation and electron impact dissociation of CO2 and CO, which are then transported to the
nightside by the subsolar to antisolar general circulation, where they recombine to create metastable
O2(a1Δ) molecules. Their radiative deexcitation produces the O2(a1Δ) nightglow with a maximum
near the antisolar point. However, VIRTIS individual observations indicate that the O2(a1Δ)
nightglow emission is highly variable, both in intensity and location. Individual observations acquired
during a short period of time can also be grouped sequentially. Bright emission patches can thus be
tracked and both their displacement and intensity variations can be analyzed. The peak intensity can
vary from 1 to 6 megaRayleighs. We show that the emission peak moves with a mean value of ~80
m s-1, in good agreement with an earlier study by Hueso et al. (2008). The velocity vector in
intensity and direction is evaluated approximately every 60 min. These displacements are highly
variable, but some dynamical characteristics can be deduced from the observations. These results
will be compared with other results of velocity determination in the upper mesosphere.
Abstract Nr. 132
The variable upper atmosphere of Venus - data from drag and torque measurements by
Venus Express
Håkan Svedhem , ESA/ESTEC, Research and Space Science Dep., Noordwijk, Netherlands
(hsvedhem@rssd.esa.int); Ingo Müller-Wodarg , Imperial College, London, UK; Pascal Rosenblatt
, Royal Observatory, Brussels, Belgium
Until recently the only information on the structure of the polar upper atmosphere of Venus available
has been based on the reference atmosphere models such as the VTS3 or VIRA models. These
models extrarpolate the values from low latitudes to high latitudes by using equivalent solar zenith
angles. New measurements by Venus Express show that such extrapolations not always give correct
results and that there is a permanent overestimate of the density at high latitudes.
These new results have been reached by using two different but related techniques, both using an
atmospheric drag effect on the spacecraft. By reducing the pericentre altitude the total mass density
in the altitude range 150-200km can be measured in situ by monitoring the orbital decay caused by
the drag on the spacecraft by the atmosphere via direct tracking of the Doppler signal on the
GROUP 1 POSTER – MON‐WED – PAGE 45 telecommunication link. Such measurements have been performed with Venus Express several times
during the last years as part of the Venus Express Atmospheric Drag Experiment (VExADE). The
results indicate a large variability within only a few days and have led to questions if these variations
are real or within the uncertainty of the measurements. A completely different and independent
measurement is given by monitoring the torque asserted by the atmosphere on the spacecraft. This
is done by monitoring the momentum accumulated in the reaction wheels during the pericenter pass
and at the same time considering all other perturbing forces. This requires the spacecraft to fly in an
asymmetric attitude with respect to the center of gravity, center of drag and the velocity vector. This
technique has proven very sensitive, in particular if the geometric asymmetry is large, and offers an
additional method of measuring atmospheric densities in-situ that previously had not been explored
with the Venus Express spacecraft. Similar measurements have been done in the past by Magellan at
Venus and by Cassini at Titan. Between 2009 and 2012 several campaigns, with altitudes going as
low as 165 km, were held. The highest density measured was 7.7 10-12kg/m3 which is significantly
less than earlier models predict. The results largely confirm the density measurements by the
VExADE drag measurements and add to the confidence in the results from these measurements. By
using these drag and torque results and assuming a hydrostatic diffusive equilibrium atmosphere a
new model has been constructed.
Abstract Nr. 111
Mapping the lower thermosphere of Venus using VIRTIS/VEx Nadir non-LTE observations
at 4.3 um
López-Valverde, Miguel A. , IAA/CSIC, Granada (Spain); Peralta, Javier, IAA/CSIC, Granada (Spain);
Gilli, Gabriella, IAA/CSIC, Granada (Spain); Drossart, Pierre, LESIA, Observatoire de Paris (France);
Piccioni, Giuseppe, IAPS, Rome (Italy)
A specific set of measurements by VIRTIS/Venus Express is analyzed, that of the infrared emissions
of CO2 during daytime in a nadir geometry at 4.3um, originated under breakdown of local
thermodynamic equilibrum (LTE) in the upper atmosphere.
The scientific exploitation of this nadir dataset is challenging. Non-LTE observations are normally
taken in the limb and their vertical variation is used to sound the atmosphere in detail. Our goal here
is not the vertical but the spatial variability on the horizontal at the layer of the emission, which
according to our non-LTE model is located in the upper mesosphere/lower thermosphere of Venus, at
about 110-135 km.
Non-LTE theory predicts such CO2 emissions after direct solar pumping to be observed in nadir, to
present large variations with SZA and emission angle and to consist of a mixture of individual
contributions from a large number of different ro-vibrational CO2 bands, whose intensities respond
to diverse collisional and radiative relaxations. All this is confirmed by the measurements, however,
a precise simulation is difficult. In addition to the non-LTE complexities and uncertainties, a careful
geometrical ray-tracing at the monochromatic level is needed, as well as a correction for the
contamination from solar scattering at the Venus clouds.
We will present the peculiarities of these non-LTE emissions, the selection of observations from
VIRTIS-H, the best fits to the measurements achieved with our simulations, and the results of the
inversion scheme designed to obtain and map the temperatures in the Venus lower thermosphere.
Abstract Nr. 56
Visible and Infrared nightglow investigation in the Venus atmosphere by means of VIRTIS
on Venus Express
Migliorini Alessandra, IAPS-INAF, Rome; Piccioni Giuseppe, IAPS-INAF, Rome; Gérard JeanClaude, LPAP,ULg, Liége; Soret Lauriane, LPap, ULg, Liége; Slanger Tom G., MPL, SRI International;
Politi Romolo, IAPS-INAF, Rome; Snels Marcel, ISAC-CNR, Rome; Drossart Pierre, LESIA,
Observatory of Paris, Paris
The oxygen Venus nightglow emissions in the visible spectral range have been known since the early
observations from the Venera spacecraft. The major emissions are attributed to the Herzberg II band
system, observed in the 400-700 nm spectral range. Additional transitions, belonging to the
GROUP 1 POSTER – MON‐WED – PAGE 46 Chamberlain system, have been also identified. Recent limb observations with the VIRTIS instrument
on board Venus Express allowed to study the vertical distribution of the Herzberg II system of O2, in
particular the 0-v''(with v''= 7 to 13) bands. The integrated intensity of the Herzberg II bands with
v''= 7-11 varies in the range 83.8-116.4 kR at peak, for the analyzed data. The peak intensity of the
emission is observed at an altitude of 93-98 km for the same dataset.
Three bands of the Chamberlain system, centred at 560nm, 605 nm, and 657 nm have been
identified as well in the VIRTIS data. The peak position is observed about 4 km higher than the
emissions due to the Herzberg II and the IR atmospheric systems. This puzzling issue can be
addressed with a 1-dimensional model developed starting from realistic O2 and CO2density profiles.
By adjusting the uncertainquenching coefficients, we are able to reproduce the peak intensities and
altitudes of the three systems.
Finally, a comparison with simultaneous observations in the IR shows that the IR atmospheric bands
peak 1-2 km higher than the Herzberg II system bands. This is also in agreement with the
simulations of the 1-D model.
Abstract Nr. 99
Global imaging of the Venus O2 visible nightglow with the Venus Monitoring Camera
García-Muñoz Antonio, ESA/RSSD, ESTEC, Noordwijk, Netherlands ; Hueso Ricardo, Dpto. Física
Aplicada I, Escuela Técnica Superior de Ingeniería, UPV/EHU, Bilbao (Spain); Sanchez-Lavega
Agustin, Dpto. Física Aplicada I, Escuela Técnica Superior de Ingeniería, UPV/EHU, Bilbao (Spain);
Markiewicz Wojciech J. , (6) Max Planck Institute for Solar System Research, Katlenburg-Lindau,
Germany; Titov Dimitri V., ESA/RSSD, ESTEC, Noordwijk, Netherlands ; Witasse Olivier, ESA/RSSD,
ESTEC, Noordwijk, Netherlands ; Opitz Andrea, ESA/RSSD, ESTEC, Noordwijk, Netherlands
We have investigated the Venus O2 visible nightglow with imagery from the Venus Monitoring
Camera (VMC) on Venus Express. The images show a faint but distinct emitting layer at about 100
km altitude attributed to the so-called Herzberg II system of O2, first detected in the Venus
atmosphere by the Venera 9 and 10 missions. The VMC visible filter (passband of 502-568 nm at 1/4
maximum transmission) is most sensitive to the v”=9, 10 bands of the c(0)-X(v”) progression, that
occur at 513 and 551 nm, respectively. Drawing from data collected between April 2007 and January
2011, we studied the emission’s global distribution. The inferred limb-viewing intensities are on the
order of 150 kR at the lower latitudes and seem to drop somewhat towards the poles. The emission
is generally stable, although there are episodes when the intensities rise up to 500 kR. Our mapping
complements past in-orbit surveys of the O2 visible nightglow, namely those from the Venera
missions and Pioneer Venus Orbiter, and provides simultaneous temporal, latitudinal/longitudinal and
vertical resolution of the emission. We compare a set of VMC observations with coincident
measurements of the O2nightglow at 1.27 micron made with the Visible and Infrared Thermal
Imaging Spectrometer, also on Venus Express. We do not find conclusive evidence for a different
behavior between the visible and near-infrared emissions.
Abstract Nr. 41
The Effect of Coronal Mass Ejections and Solar Flares on the Venusian Nightglow
Gray, Candace, New Mexico State University; Chanover, New Mexico State University; Tom
Slanger, SRI International
The study of planetary nightglow provides us with ways of determining a planet's
upper atmosphere composition, chemistry, transport, and evolution. Venus has
several strong nightglow features, including the O(1S-1D) transition at 5577.3 Å
(oxygen green line). This feature is known to be highly temporally variable, unlike
the Earth's green line. The reason for this variability is unknown. We propose that
the variability is due to large amounts of extreme ultraviolet (EUV) light and/or
charged particles that interact with Venus' upper atmosphere following solar flare
GROUP 1 POSTER – MON‐WED – PAGE 47 eruptions, coronal mass ejections (CMEs), and strong solar wind streams (SWS)
from the Sun.
To test our hypothesis, we observed Venus on the 3.5m Astrophysical Research
Consortium (ARC) telescope at Apache Point Observatory with the ARC high
resolution echelle spectrograph. Observations were made between April - July 2012
following large solar events. We detected Venusian green line after two separate
events: after a CME impact not preceded by a flare, and after an X-flare eruption and
a large CME impact. Less than a day after the large CME impact, we found the
Venusian green line emission strength to be comparable to the original detection,
which was the strongest emission ever detected. The green line strength decayed
over the next two nights. From this we conclude that charged particles from CMEs
are a likely source of green line emission. We did not detect emission after solar
flares that were not followed by a CME, but there are several reasons this may have
occurred, as we will discuss.
Abstract Nr. 134
Mt. Etna and the Eistla volcanoes: Comparative studies to constrain venusian volcano
evolution and flow emplacement
S.W. Anderson, ; E.R. Stofan, ; S.E. Smrekar,
The magnitude and change of volumetric flow rates at basaltic volcanoes are known to affect both
the morphology of individual lava flows, and the shape of the volcano itself. The episodic nature of
most eruptions are a function of how energy is stored, and released in volcanic systems, which in
turn affects the surface morphology of the erupted products. Therefore, a careful analysis of basaltic
surfaces and vent locations can be used as a means by which to understand the both the volcanic
history and eruption dynamics for older volcanoes and those in planetary environments. Previous
studies of Mount Etna (Italy), Kilauea (Hawaii) and Krafla (Iceland) volcanoes show effusion rate
trends that relate to both surface morphology and eruption dynamics that can be used to assess the
formation of venusian volcanoes. Sif Mons shows gross morphological characteristics, such as a
central vent complex and flows with varying surface morphologies that are similar to that found at
Mount Etna, suggesting that eruptions are fed by overflow of the time-averaged magma supply with
individual eruptive events that are characterized by steady effusion and long-term eruption rates. In
contrast, Gula shows a well-establish rift system and a less complex surrounding flow field that are
typically produced by eruptions that have high intensity peaks early followed by exponentiallydecreasing effusion and long-term eruption rates.
Abstract Nr. 135
Temperatures in Venus' Lower Thermosphere: Comparison of VTGCM and SOIR Profiles at
the Terminator
S. Bougher , U. of Michigan; C. Parkinson , U. of Michigan; A. Brecht, NASA ARC, CA, USA ; J.
Fischer , GSFC, Greenbelt, MD, USA; A-C. Vandaele , BIRA, Brussels, Belgium; V. Wilquet , BIRA,
Brussels, Belgium; A. Mahieux , BIRA, Brussels, Belgium
The thermospheric general circulation model for Venus (VTGCM) produces temperatures, densities,
and winds over ~70-200 km that can be compared to Venus Express measurements (Brecht et al.
2012). This study will examine the modeled temperatures and the corresponding CO2 density
distributions near the terminators in comparison with observations from the Solar Occultation in the
InfraRed (SOIR) instrument. Currently, SOIR terminator profiles of CO2 densities and temperatures
GROUP 1 POSTER – MON‐WED – PAGE 48 have been compiled for 79-selected orbits obtained between 2006-2011 (Mahieux et al. 2012).
These profiles represent a global view of the atmospheric characteristics at the Venusian terminator
over an altitude range from ~70 to 170 km. These profiles show a general trend revealing a strong
temperature minimum around 125 km and the weaker of two temperature maxima near 100-115
km. The temperature structure is reflected in the CO2 density profiles. These profiles provide detailed
constraints for global circulation models of the upper atmosphere of Venus, including their simulated
temperatures and underlying thermal balances.
For comparisons, VTGCM temperature profiles are extracted from the terminator that corresponds to
five latitude bins (0-30N, 30-60N, 60-70N, 70-80N, 80-90N) presently used in the SOIR data
analysis. Sensitivity tests with the VTGCM are conducted to show possible sources of variability in
the temperature profiles. Also, the impacts of upward propagating waves (e.g. Kelvin wave) on these
temperatures are examined. The study will help characterize Venus’ upper atmosphere near the
terminators and provide insight into the physical mechanisms responsible for the mean structure and
its variability.
GROUP 1 POSTER – MON‐WED – PAGE 49 Group 2 poster – Wed‐Fri Abstract Nr. 97
Observations of the near-IR nightside windows of Venus during Maxwell Montes transits
by SPICAV IR onboard Venus Express
Fedorova Anna, Space Research Institute (IKI); Moscow Institute of Physics and Technology (MIPT);
Bézard Bruno, LESIA, Observatoire de Paris, section de Meudon, CNRS; Bertaux JeanLoup, LATMOS-UVSQ; Korablev Oleg, Space Research Institute (IKI); Moscow Institute of Physics
and Technology (MIPT)
One of the difficulties in modeling of Venus’ nightside windows is an additional CO2 continuum
opacity due to collision-induced CO2 bands and/or extreme far wings of strong allowed CO2 bands.
Characterization of the CO2 continuum absorption at near-IR wavelengths and also search for a
possible vertical gradient of minor species near the surface require observations over different
surface elevations. The largest change of altitudes occurs during a passage above Maxwell Montes at
high northern latitudes. In 2011 and 2012 the SPICAV IR performed two sets of observations over
Maxwell Montes during 8 and 6 orbits, respectively, in the 1.10-, 1.18- and 1.28-μm windows with a
variation of surface altitude from -2 to 9 km. We will present results on the CO2 continuum
absorption for the 1.10- and 1.18-μm windows and an investigation of the H2O mixing ratio gradient
from the SPICAV data.
Abstract Nr. 16
Ground-based IR observation of oxygen isotope ratios in the Venus atmosphere
IWAGAMI Naomoto HASHIMOTO George ROBERT Séverine O, University of Tokyo Okayama
University Belgian Institute of Space Aeronomy Senshu University University of Tokyo
The oxygen isotope ratios 17O/16O and 18O/16O in the solar system show a clear systematic
relation. And the relation differs planet by planet. For example, the 17O/16O ratio as a function
of 18O/16O ratio in Mars appears to be larger than that in the Earth-Moon system by 0.05 %.
This fact indicates that the proto-Earth-Mars matter was so well mixed but with a systematic
localization. In such a way, the isotope ratios may provide information about the origin and
evolution of the planets. However, 17O/16O ratio in Venus has never been quantified, and may
provide further information about the mixing history of the early solar system if measured.
The ratios may be quantified by ground-based CO2 IR spectroscopic measurements. By
assuming a use of IRTF CSHELL spectrometer with a nominal resolution of 42000, we looked
for suitable wavenumber regions to quantify the17O/18O and 18O/16O ratios. The suitable region
for the former is found at 2648 cm-1, and for the latter at 4582 cm-1. Preliminary analysis shows
that δ17O=+38±53 ‰ and δ18O=-41±52 ‰ where the uncertainties include random errors only;
they coincide with those of the earth-moon system within random errors. However, the
systematic error anticipated in the line intensities seems to be larger.
Abstract Nr. 67
Abundance of sulfuric acid vapor in the Venus atmosphere derived from the Venus Express
Radio Science Experiment VeRa
Oschlisniok Janusz, Rheinisches Institut für Umweltforschung, Abteilung Planetenforschung,
Universität zu Köln, Köln, Germany; Pätzold, Martin, Rheinisches Institut für Umweltforschung,
Abteilung Planetenforschung, Universität zu Köln, Köln, Germany; Häusler, Bernd, Institut für
GROUP 2 POSTER – WED‐FRI ‐ PAGE 50 Raumfahrttechnik, Universität der Bundeswehr München, Neubiberg, Germany; Tellmann,
Silvia, Rheinisches Institut für Umweltforschung, Abteilung Planetenforschung, Universität zu Köln,
Köln, Germany; Bird, Michael K., Rheinisches Institut für Umweltforschung, Abteilung
Planetenforschung, Universität zu Köln, Köln, Germany; Andert, Thomas, Institut für
Raumfahrttechnik, Universität der Bundeswehr München, Neubiberg, Germany; Remus,
Stefan, European Space Astronomy Centre (ESAC), Villanueva, Spanien
The radio science experiment VeRa probes the Venus atmosphere with radio signals at 3.6 cm (XBand) and 13 cm (S-Band) wavelengths. The planet Venus is enshrouded by a roughly 20 km thick
cloud layer extending from 50 km to 70 km altitude. While the clouds are mostly composed of liquid
sulfuric acid droplets, a haze layer of sulfuric acid vapor exists below the clouds. A decrease in the
signal intensity caused by gaseous H2SO4 absorption is observed in VeRa radio occultation
experiments below the cloud region (Oschlisniok et al., 2012). This radio absorption is used to
determine the abundance of H2SO4 in the cloud and sub-cloud region. The VEX orbit enables study of
the global distribution of gaseous sulfuric acid abundance. Vertical absorptivity profiles and the
resulting sulfuric acid vapor profiles are presented and compared with previous missions. Together
with results from other Venus Express experiments, the derived global distribution of gaseous
sulfuric acid is used to study Venus atmospheric dynamics.
Abstract Nr. 128
Water vapor near the cloud tops of Venus from VIRTIS Venus Express day side data
Cottini Valeria, NASA GSFC, Greenbelt, USA; Ignatiev Nikolay, Space Research Institute or Russian
Academy of Sciences (IKI RAN), Moscow, Russia; Piccioni Giuseppe, INAF IAPS, Roma, Italy;
Drossart P. , LESIA, Observatoire de Paris, Meudon, France; Markiewicz W., Max Planck Institute for
Solar System Research, Katlenburg-Lindau, Germany
We observe the dayside of Venus with VIRTIS [1] instrument on board Venus Express to measure
the cloud top altitude and water vapor abundance near this level. An extended analysis of these
measurements by Cottini et al. [2] was limited by a northern hemisphere due to geometry of
observations on first 1000 orbits of the mission. Further measurements significantly improve the
latitudinal coverage and demonstrated symmetric behavior of clouds and water vapor in both
hemispheres.
[1] Drossart, P., Piccioni, G., and 29 co-authors: Scientific goals for the observation of Venus by
VIRTIS on ESA/Venus Express mission, Planet. Space Sci., Vol. 55, pp. 1653-1672, 2007.
[2 Cottini, V., Ignatiev, N. I., Piccioni, G., Drossart, P., Grassi, D., and Markiewicz, W. J.: Water
vapor near the cloud tops of Venus from Venus Express/VIRTIS dayside data, Icarus, Vol. 217, pp.
561-569, 2012.
Abstract Nr. 44
On the Possibility of Gamma Ray Flashes from Venusian Lightning
Lorenz, Ralph, JHU Applied Physics Lab
Venus lightning remains mysterious, with some electromagnetic indications of discharges but
predominantly negative optical searches. In the mid-1990s, earth-orbiting astrophysical
observatories surprisingly discovered a new window on lightning - terrestrial gamma ray flashes
(TGFs) produced by the bremmstrahlung of relativistic electrons accelerated upwards from the
lightning discharge. Could this phenomenon occur on Venus ?
In fact, the Pioneer Venus Orbiter (PVO), in orbit at Venus for some 14 years, carried an Orbiter
Gamma Ray Detector (OGBD) for astrophysical studies. Since PVO burned up on entry in 1992,
before TGFs were discovered, we do not believe the OGBD data has been examined for Venusian
flashes. We have correlated the OGBD data from NSSDC with the ephemeris from the PDS
Planetary Magnetospheres node to search for variations in count rate that may be associated with
altitude, geographic location and time of day. Unfortunately the data are too coarsely binned in time
to detect an obvious signal.
GROUP 2 POSTER – WED‐FRI ‐ PAGE 51 Nonetheless, the possibility remains that future gamma ray instrumentation in Venus orbit could
search more deeply for Venus Gamma-ray Flashes (VGFs). To inform such proposals, we have set
up a gamma-ray propagation model for the Venus atmosphere using full photon and electron physics
in the MCNPX code (Monte Carlo Neutral Particle eXtended) to explore at what altitude VGFs must
occur to be visible from orbit.
Abstract Nr. 90
Modeling and observations of mesospheric sulfur chemistry
Mills, Australian National University and Space Science Institute; Sandor, Space Science Institute;
Clancy, Space Science Institute
Observations of SO2 and SO in Venus' mesosphere have raised a number of interesting questions,
including the consistent detection of a layer above 85 km with greater gas-phase mixing ratios than
are found below 85 km, substantial temporal and time-of-day variations in mixing ratios, and
substantial variations in the SO2/SO ratio. The last is an important observational test for
photochemical models of the sulfur oxide chemistry in Venus' mesosphere. Initial comparisons of
model simulations and observations found reasonable agreement on the day side (albeit with
considerable variability in the observations) and factor of 100 differences on the night side. Further
analysis of the observations has identifed distinct and different patterns in the SO2/SO ratio on the
day and night sides. This poster will discuss these analyses and their interpretation via time-of-day
model simulations.
Abstract Nr. 35
Spectral inventory of the SOIR spectra onboard Venus Express
Robert Séverine, IASB-BIRA; Mahieux Arnaud, IASB-BIRA; Wilquet Valérie, IASB-BIRA; Drummond
Rachel, IASB-BIRA; Vandaele Ann Carine, IASB-BIRA
The set of spectra recorded by the SOIR instrument on board Venus Express have been carefully
studied from a spectroscopic point of view. The SOIR instrument combines an echelle spectrometer
and an Acousto-Optical Tunable Filter for order selection. It performs solar occultation
measurements in the IR region (2.2 - 4.4 µm) at a resolution of 0.10 - 0.24 cm-1. The wavelength
range probed by SOIR allows a detailed chemical inventory of the Venus atmosphere above the
cloud layer (65 to 180 km) with emphasis on the vertical distribution of gases (CO2, CO, H2O, HCl,
HF…).
The sensitivity of the SOIR instrument and the high concentration of CO2 on Venus, coupled with the
long absorption paths sounded during solar occultation observations, enable us to detect weak
absorption bands of rare CO2 isotopologues.
Different tools (manual and automatic calibration, automatic assignment with respect to HITRAN
2008) were developed and applied to the SOIR spectra leading to the creation of the wavenumber
list of each observed line.
The tools used to calibrate the spectra and to produce the line list will be described extensively for a
selected number of orbits.
Abstract Nr. 62
Three-dimensional modelling of Venus photochemistry
Stolzenbach Aurelien, LATMOS; Lefevre Franck, LATMOS; Lebonnois Sebastien, LMD; Maattanen
Anni, LATMOS
We have developed a new code of the Venus atmospheric chemistry based on our photochemical
model already in use for Mars (e.g., Lefèvre et al., J. Geophys. Res., 2004). For Venus, the code also
includes a parameterized treatment of cloud microphysics that computes the size distribution and
GROUP 2 POSTER – WED‐FRI ‐ PAGE 52 composition of sulphuric acid droplets. Recently, we coupled this photochemical-microphysical
package to the LMD general circulation model (Lebonnois et al., J. Geophys. Res., 2010). We will
describe preliminary results obtained with this first three-dimensional model of the Venus
photochemistry. The distribution of key chemical species as well as their variations in space and time
will be compared to observations performed from Venus Express and from the Earth.
Abstract Nr. 72
Variations in Venus’ cloud top SO2 and SO gas density with latitude and time of day
Jessup, Kandis-Lea, Southwest Research Institute
Venus’ H2SO4 clouds are formed from SO2 gas via the sulfur-oxidation cycle, beginning with
SO2 photolysis; followed by the formation of SO3 via SO2oxidation, which then reacts with H2O
forming H2SO4. In spite of decades of effort, we do not fully understand the way in which the sulfuroxide cycle proceeds (Sandor et al. 2010, Sandor et al. 2011). In order to establish patterns in the
sulfur-oxide photochemical behavior as a function of latitude and time of day 200-300 nm HST/STIS
observations were obtained on Dec 28, 2010, Jan 22, 2011 and Jan 27, 2011 that recorded Venus’
cloud top (65-75 km) SO2 and SO gas absorption signatures at 0.3 nm spectral resolution at
latitudes ranging from 20N to 60 S at multiple times of day (Jessup et al. 2012). We present an
overview of the results, showing that i) an SO2 abundance of ~ 10-350 ppb was retrieved, consistent
with previous Venus Express SPICAV observations made at ±25° latitude (Marcq et al. 2011, Marcq
et al. 2013); and, ii) similar to the SPICAV observations, the observed SO2 gas density decreased as
the latitude increased from 20 S towards 20 N. The observed SO2 gas density also decreased with
local time from the morning terminator towards noon, as expected for a gas density controlled by
photochemical destruction; while variation in the observed SO gas density per latitude paralleled
that of the SO2 gas, indicating that the latitudinal distribution of the SO gas density was NOT solely
controlled by SO2 photolysis. Interpretation of the data is on-going.
Abstract Nr. 102
VIRTIS-VEX data analysis for the study of the Venus
Politi Romolo, INAF-IAPS, via del Fosso del Cavaliere, 100, 00133, Rome, Italy; Migliorini
Alessandra, INAF-IAPS, via del Fosso del Cavaliere, 100, 00133, Rome, Italy; Piccioni
Giuseppe, INAF-IAPS, via del Fosso del Cavaliere, 100, 00133, Rome, Italy; Drossart Pierre, LESIA,
5, place Jules Janssen, 92195 Meudon, Paris, France
The Venus Express spacecraft has performed more then 2500 orbits around Venus in more than 6
years of mission. In this time VIRTIS was able to acquire more than 1 TB of data using the visible
channel. . In this work we analyze the Bright Factor evolution, on short and long time scales,
through the available dataset. The Bright Factor is defined as the ratio between the Venus' VIRTIS
spectrum, M-Vis channel, and the Solar spectrum, scaled to the Venus distance. The geometric
configuration of the observation is taken in account dividing the spectrum acquired from VIRTIS by a
factor proportional to the cosine of the incidence angle. The VIRTIS data are filtered on the local
time in order to select only the data from the day side, and the emergence angle, by excluding too
high angles of observations. The range explored is between 300 and 1000 nm. We start from an
analysis of a global averaged map, that cover all the mission period, to arrive to the single orbit
maps, through seasonal variations. We also report the temporal evolution at selected locations and
specific wavelengths. Finally, we report the profiles of the Bright Factor versus latitude and local time
with the help of 3D maps.
Abstract Nr. 42
Progress in a refined calibration of the Venus Express VIRTIS-M instrument with
application to Venus’s ultraviolet absorber
Carlson, Robert W., Jet Propulsion Laboratory, California Institute of Technology; Piccioni,
GROUP 2 POSTER – WED‐FRI ‐ PAGE 53 Giuseppe, Istituto di Astrofisica e Planetologia Spaziali
The VIRTIS experiment on Venus Express has collected a wealth of spectra that are useful for
studying the ultraviolet absorber present in Venus’s clouds and for possibly identifying the species
providing this absorption. However the spectrometer, similar to most grating instruments, suffers
from the presence of scattered light that has hindered easy interpretation of the spectra. We have
developed methods to satisfactorily remove the scattered light and have recalibrated the response
using standard star spectra. Analysis of Venus spectra is now proceeding and preliminary scientific
results, as well as the description of the refinement methods, will be presented in the poster.
Abstract Nr. 77
Venusian upper hazes observed by Imaging-Polarimetry system HOPS
Enomoto Takayuki, The Graduate University for Advanced Studies; Satoh Takehiko, Japan Aerospace
Exploration Agency; Yoshikazu Nakatani, Kyoto University; Nakakushi Takashi, Wakayama
University; Sato Takao, NICT; Ohtsuki Shoko, Senshu University; Hosouchi Mayu, University of
Tokyo
Physical properties of the aerosols in the Venusian upper atmosphere can be derived by
measuring the polarization of light scattered by them. Kawabata et al. [1980] obtained polarization
maps of Venus from the data of Orbiter Cloud Photopolarimeter (OCPP) onboard the Pioneer Venus
Orbiter, and found numerous haze particles distributed mainly on polar region. The variability of
hazes and clouds can change latitudinal balance of solar absorption and atmospheric dynamics.
Two dimensional polarization maps are needless to say advantageous as they allow us to
selectively pick up the local characteristics. We developed a planetary imaging-polarimetry system
HOPS (Hida Optical Polarimetry System), which can take polarization maps. The optical system of
HOPS includes a Wollaston prism and a half wave retarder, and the observation channels are 930,
647(650), 548(546), and 438nm.
For the purpose of monitoring of Venusian upper hazes, we performed observations at the
Hida observatory of Kyoto Univ. in May, Aug., and Oct. 2012. From quick-looks of the data, it may
be indicated that the distribution of haze particles at the time of HOPS observations is somewhat
similar to that was observed by PVO/OCPP. We are planning to observe at other phase angles and
developing the computational code for multiple light scattering including the effect of polarization for
the purpose of quantitative evaluations.
Abstract Nr. 76
Latitudinal cloud structure in the Venusian northern hemisphere
Express/VIRTIS observations
evaluated from Venus
M. Kuroda, Tohoku Univ.; Y. Kasaba, Tohoku Univ.; T. Kuroda, Tohoku Univ.; P. Drossart, Obs. de
Paris; G. Piccioni, INAF-IAPS
The averaged latitudinal distributions of Venusian northern cloud, i.e, its opacity, temperature at the
top, altitude at the top and the carbon monoxide under the cloud, were evaluated from the Venus
Express/VIRTIS nadir observations. There are several characteristics related to the polar region
clouds: (1) The cloud optical thickness around the polar region in 65-80° N is 1.5 times larger than
that in the mid-latitudes. It suggests that the number of cloud particles is larger or the optical
characteristics of cloud particles are different. (2) The averaged cloud top temperature is gradually
decreases from 0-40° N (232±2 K) to 70° N (223±5 K), and increases again to the north pole
(233±6 K), while the averaged cloud top altitude monotonously decreases from the equator
(68.2±1.6 km) to the north pole (58.3±1.0 km). Both suggest that the Venusian cold and hot polar
structures are lower cloud top regions. (3) The averaged CO mixing ratio under the cloud increases
from the equator (16±3 ppm) to 70o N (24±5 ppm), and decreases to 80o N (19±5 ppm). This
profile has a negative correlation to the cloud top temperature. Since CO under the cloud is
transported from the upper cloud layer, it suggests that the cold collar is the down-welling region.
Those results are used as the baseline of the Venus General Circulation Model (VGCM) [Kuroda et
al., in this meeting.]
GROUP 2 POSTER – WED‐FRI ‐ PAGE 54 Abstract Nr. 23
Study of Venus cloud layers by polarimetry using SPICAV/VEx
Rossi Loic, LATMOS/UVSQ; Marcq Emmanuel, LATMOS/UVSQ; Montmessin Franck, LATMOS/CNRS;
Fedorova Anna, Space Research Institute (IKI); Bertaux Jean-Loup, LATMOS/CNRS
The study of Venus's cloud layers is important in order to understand the structure and dynamics of
its atmosphere. The main cloud layers between 50 and 70 km are thought to consist in ~1 um radius
droplets of a H2SO4-H2O solution. Nevertheless, the composition and the size distribution of the
droplets are difficult to constrain more precisely. In the early 1980s, Kawabata et al.(1980) used the
polarization data from Pioneer Venus' OCPP instrument to constrain the properties of the haze. We
introduce here the model we developed, based on the BH-MIE scattering model. Taking into account
the same size distribution of droplets as Kawabata et al., we obtained the polarization degree after a
single Mie scattering given the effective radius and variance of the distribution and the refractive
index of the droplets. We also present the first application of our model to the so-far unexploited
SPICAV-IR polarization data under the single scattering assumption. We then plan to integrate our
model into a radiative transfer model which will take into account the multiple scattering. With
polarization and phase function observations in wavelengths ranging from 650 to 1625 nm, we will
be able to put better constraints on the properties of cloud and haze particles, with a primary focus
on the cloud droplets characterization.
Abstract Nr. 28
High-altitude source for the Venus’ upper haze found by SOIR/Venus Express
TAKAGI Seiko, University of Tokyo
The Solar Occultation at InfraRed (SOIR) on board Venus Express is designed to measure the
atmospheric transmission at high altitudes (60-220 km) in the IR (2.2-4.3 µm) with high resolution
by solar occultation. The SOIR data obtained in 2006-2009 are analyzed to obtain knowledge of the
Venus’ upper haze layer. Vertical distributions of upper haze extinction and mixing ratio (defined as
extinction divided by the total density) are derived from the SOIR data. Mixing ratio is found to
increase at 90 km and above at both high and low latitudes. It means that haze production is
present in this altitude region competing with the vertical eddy diffusion. From comparison with the
vertical distributions of SO and SO2 mixing ratios reported by Belyaev et al. (2012), it is speculated
that sulfide is closely related to the haze chemistry. At high latitude, mixing ratio is found to be
constant at 70-90 km. It means that the vertical eddy diffusion is dominant over the chemistry.
Whereas at low latitudes, mixing ratio decreases with altitude at 70-90 km. It means that haze
production in the cloud-top region is competing with the vertical eddy diffusion.
Abstract Nr. 53
Simulation of the formation, evaporation and transport of sulfuric acid clouds on Venus
using a general circulation model
Takeshi Kuroda, Tohoku University; Fumiya Kato, Simulation of the formation, evaporation and
transport of sulfuric acid clouds on Venus using a general circulation model; Akira Nitta, The
University of Tokyo; Morihiro Kuroda, Tohoku University; Yasumasa Kasaba, Tohoku University;
Masaaki Takahashi, The University of Tokyo
Sulfuric acid clouds, which exist in 50-70 km altitudes of the Venus' atmosphere, are considered to
have a strong influence on the thermal balance. We are investigating the formation and movement
of the clouds using a Venus general circulation model (VGCM), and showing the preliminary results
in this presentation.
Our VGCM is based on the CCSR/NIES/FRCGC AGCM [Ikeda, 2011] which extends from the surface
up to ~95 km. The model reproduces the consistent zonal wind fields of super-rotation with
observations in the cloud layer with the forcing of gravity waves and a new comprehensive radiative
transfer model considering the effects of molecules (CO2, H2O, CO, SO2 and OCS), 75% H2SO4 cloud
GROUP 2 POSTER – WED‐FRI ‐ PAGE 55 particles and unknown UV absorber at the cloud top.
We have implemented the radiatively-passive tracers of 75% H2SO4 cloud particles with four
different size modes into the VGCM. The condensation and evaporation processes between the
clouds and H2SO4 vapor are implemented, and the formed clouds are distributed into the four size
modes according to the observed abundance ratios at each altitude. The release of latent head
during condensation is also implemented.
After the calculations for 1 Venusian day (117 terrestrial days) from the horizontally-uniform states,
the cloud abundances of all size modes tended to increase in higher latitudes in comparison with the
simulations without the condensation/evaporation processes [Kuroda M. et al., 2013]. This may be
because the evaporations of clouds enhance the transport of H2SO4 to the polar regions by the
Hadley circulation.
Abstract Nr. 21
Planetary Radio Interferometry and Doppler Experiments for current and future Venusian
missions.
Giuseppe Cimo, Joint Institute for VLBI in Europe; Guifre Molera Calves, Joint Institute for VLBI in
Europe; Sergei Pogrebenko,Joint Institute for VLBI in Europe; Dmitry Duev, Joint Institute for VLBI
in Europe; Tatiana Bocanegra Bohamon, Joint Institute for VLBI in Europe; Leonid Gurvits, Joint
Institute for VLBI in Europe
Planetary Radio Interferometry and Doppler Experiment (PRIDE) is a technique to track spacecraft
using Very Long Baseline Interferometry (VLBI) in order to estimate state-vectors with high
accuracy. PRIDE provides a wide range of scientific outcomes, from geodynamics to fundamental
physics. The Venus Express (VEX) spacecraft has been the main target for tests and scientific
experiments of the PRIDE team at the Joint Institute for VLBI in Europe (JIVE). My contribution will
focus on PRIDE measurements of the Venus Express spacecraft. I will talk about our VLBI
observations of the VEX signal presenting the scientific outcomes of these experiments. A number of
VLBI images of the VEX spacecraft will be presented, including data of the latest Venus atmospheric
drag campaign, when the VEX periapsis was lowered in order to study the upper atmosphere of
Venus above its North Pole.
Abstract Nr. 31
Interplanetary scintillations study retrieved from Venus Express communications signal
Molera Calves, Guifre, Joint Institute for VLBI in Europe
Very Long Baseline Interfererometry (VLBI) and Doppler tracking is one of the most powerful tools
for determining accurately the position of a spacecraft. The Planetary Radio Interferometry and
Doppler Experiment (PRIDE) has been included as a part of the scientific suite by a number of future
planetary science missions. PRIDE provides estimates of spacecraft state vectors based on VLBI
phase referencing and radial Doppler measurements. Furthermore, the phase of the transmitted
signal can be precisely extracted by using the reference clocks at the ground stations.
The fluctuations of the phase of the received signal are associated to propagation along the
interplanetary plasma. We present here a new study of the interplanetary scintillations retrieved
from the Venus Express spacecraft communication link. The observations at X-band were performed
for more than three years. We have used several radio telescopes from the European VLBI Network
(EVN) to track and monitor the behaviour of the signal at different distances and solar elongations of
VEX with respect to Earth. The results obtained provide a model of the phase scintillation index and
the Total Electron Content (TEC) for the orbit of Venus around the Solar System. These results are
important for precise orbit determination in future planetary and deep space missions.
Abstract Nr. 89
GROUP 2 POSTER – WED‐FRI ‐ PAGE 56 Using Venus Express to perform sounding experiments on lunar ionosphere
Pluchino Salvatore, INAF-IRA; Schilliro' Francesco, INAF-IRA
The Lunar Radio Occultation (LRO) program performed at the INAF-IRA Medicina and Noto
radiotelescopes consists in collecting data of the lunar Total Electron Content, at different limb
longitudes and time, in order to study long-term variation of the Moon's ionosphere. We analyse the
effects on the wave amplitude and phase modifications of VEX signals, that are correlated to the
electron density (ED) of the crossed lunar ionosphere.
Pioneer-7 in 1966 first proved the existence of a thin lunar ionosphere (ED ~4x107el/m3). Further
readings of the ED ~104el/cm3 were provided in situ by the CPLE-Experiment onboard the Apollo14
mission. Few years later, measurements performed with the spacecrafts Luna-19 and Luna-22
revealed a 10 km plasma layer, with an ED ~0.5-1x103el/cm3. Recently the interest in the study of
the lunar ionosphere has risen due to the space-agencies programs about lunar radioastronomical
stations. New measurements are important to build a long-term map of the ED distribution of the
lunar ionosphere. LRO program started at Medicina in September 2006 with the observation of
SMART-1 during its impact on the Moon. It proceeded in 2007 and 2008 with the observation of the
lunar occultations of Saturn, Venus, and Mars (where Cassini, VEX, MEX, MRO and MO were occulted
by the Moon). On Dec 2008 we performed the first Italian-VLBI tracking experiment by detecting the
VEX carrier signals with the 3 radiotelescopes (IRA and ASI). We are planning new VEX signals
tracking during the next Venus-lunar occultations: on Sep 8, 2013 and on Feb 26, 2014.
Abstract Nr. 13
A Compact, Low Power Tunable Laser Spectrometer for Trace Gas Measurement in the
Venus Atmosphere
Rafkin, Scot, Southwest Research Institute; Silver, Joel, Southwest Sciences, Inc.; Stanton,
Alan, Southwest Science, Inc.
A newly developed tunable laser spectrometer (TLS) capable of simultaneously measuring many of
the key photochemical species in the atmosphere of Venus is presented. The instrument consists of a
low-power (<10 mW) and low mass (<50 mg) vertical cavity emitting laser source and
photodetector, a multi-pass optical cell to provide a long absorption path in a compact design, and
laser driving and digital signal processing electronics. The sensor takes advantage of two key
technological developments: 1) a patented multiple-pass optical cell design that uses small mirrors
and dense spot patterns to give a long optical path with a small footprint; and 2) a low power and
compact electronics system. The design for Venus is robust in the corrosive sulfuric acid environment
and is capable of operating at temperatures of up to at least 370 K; the instrument is ideal for an
atmospheric balloon investigation at altitudes of 50 km or higher. The major advantage of this
system over previously developed TLS instruments is the multichannel gas measuring capability, an
increase in path length and sensitivity without an increase in mirror size, a dramatic decrease in
mass and power, and the robust nature of the design in a hostile environment. Most of the
instrument components and electronics are at TRL-6 with the combined system at TRL-4. Current
best estimates of total instrument mass and power are 750 mW and 1 kg, respectively.
Abstract Nr. 127
A compact, lightweight infrared heterodyne spectrometer for studies of Venus atmosphere
Rodin Alexander, Moscow Institute of Physics and Technology, Space Research Institute; Klimchuk
Artem, Moscow Institute of Physics and Technology, General Physics Institute; Nadezhdinsky
Alexander, General Physics Institute, Moscow Institute of Physics and Technology; Ignatov
Anton, Moscow Institute of Physics and Technology; Benderov Oleg, Moscow Institute of Physics and
Technology; Pereslavtseva Anastasia, Moscow Institute of Physics and Technology, General Physics
Institute
A new concept of the near- and mid-heterodyne spectrometer, based on
waveguide coupling of the signal and local oscillator radiation channels and
GROUP 2 POSTER – WED‐FRI ‐ PAGE 57 sweeping LO frequency is proposed for spacecraft application. In the nearIR spectral range, radiation of a tunable DFB diode laser, dynamically
stabilized on a reference gas cell is used as LO, is combined with the signal
channel by a single mode optical fiber. In the mid infrared range, where
single mode fiber is not available, tunable QCL laser and integrated
waveguide system are employed. This concept allows to build a compact
and lightweight instrument for solar occultations, limb and nadir
observations, which may be installed onboard future Venus orbiter.
Scientific objectives of the proposed experiment include trace gas analysis,
independent profiling of temperature and pressure and search for nonhydrostatic regions in the Venus atmosphere, observations of NLTE
emissions and high resolution Doppler measurements of wind field.
The work has been supported by the Ministry of Education and Science of
Russian Federation grant #11.G34.31.0074
Abstract Nr. 87
Analysis of MESSENGER/MASCS data during second Venus flyby
S. Perez-Hoyos, UPV/EHU; A. Garcia-Muñoz, ESTEC; A. Sanchez-Lavega, UPV/EHU; G.
Holsclaw, LASP - University of Colorado; W. McClintock, LASP - University of Colorado
In June 2007, the MESSENGER spacecraft performed its second Venus flyby during its travel to
Mercury. The spacecraft acquired several spectra of the reflected sunlight from the equatorial region
of the planet and covering from the middle ultraviolet (195nm) to the near infrared (1450 nm) using
the MASCS instrument (MUV-UVVS and VIRS channels). In this work we present an analysis of the
data and their spectral and spatial variability following the mission footprint on the Venus disk. In
order to reproduce the observed reflectivity and obtain information on the upper clouds and the
unknown UV absorber, we use XtraRT, a radiative transfer code based on DISORT and the HITRAN
database, which includes SO, SO2, CO2 and H2O absorption together with absorption and scattering
by mode-1 and mode-2 cloud particles. We discuss the sensitivity of our models to key atmospheric
parameters and some preliminary results. The MASCS observations of Venus mean a valuable
opportunity for cross-calibration with VIRTIS, the spectrometer on board the Venus Express mission.
GROUP 2 POSTER – WED‐FRI ‐ PAGE 58