Mid-Latitude / Plasmasphere Boundary Layer Radar
Millstone Hill ISR
John Foster
MIT Haystack Observatory
AMISR-Ethiopia
Workshop
March 1, 2012
MIT Millstone Hill Radar
50 Years of Discovery in the ‘Well-Understood’ Mid-Lat Ionosphere
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LOCATION
– Mid-Latitude/PBL
Trough & SAR Arc Studies
Space Weather Studies
Sub-Auroral Polarization Stream
SED: Storm Enhanced Density
Plasma redistribution
Coherent Backscatter
ERB – current-enhanced
ion line backscatter
Atmosphere – Ionosphere Coupling
(SSW)
“Build a capable system and
explore the unknown”
Haystack Observatory
Millstone Hill
Observatory
Millstone Hill Radar
Wide Coverage with the
MISA Antenna
1979
Zenith Antenna Studies of the Mid-Latitude Trough
MHR: Trough-PBL Phenomena
SAR (Stable Auroral Red) Arcs
SAPS
SAR
Broad Coverage of MidLatitude Geospace for Event
Studies & Modeling
Foster, J. C., J. M. Holt, R. E. Musgrove, and D. S.
Evans, Ionospheric Convection Associated with
Discrete Levels of Particle Precipitation,
Geophys. Res. Lett., 13, 656-659, 1986.
ISRIM Empirical Ionospheric Models
• Statistically constructed from
5+ decades of ISR data
• Local and regional models
available
• Coverage through E and F
region (topside in some cases)
• Ne, Te, Ti, Velocity
• Empirical convection models
also available
J. M. Holt, S.-R. Zhang (MIT)
Publications: 2002 and following
Model code, runs available
at MIT Haystack website
Parameterized: F10.7, Ap, DOY, SLT, Gdlat
ISRIM Empirical Ionospheric Models
Statistical Characterization of the Madrigal ISR Data Archives
Long-term temperature changes in the upper atmosphere
A significant long-term cooling trend in the upper atmosphere has been detected using
incoherent scatter radar observations made over nearly 40 years above Millstone Hill.
This cooling is associated with the so-called global warming in the ground temperature,
and has impact on human space activities due to atmospheric density reduction. (left, ion
temperature trends in K/year; right, ion temperature trends in %/decade. Midday data.)
Location: Plasmasphere / Ring Current M-I Studies
Discovery: Sub-Auroral Polarization Stream
Empirical 2-Cell
Convection plus
SAPS Electric Field
SAPS Convection Channel
Yeh et al.[1991]
Ring Current M-I Coupling drives SAPS
(Sub Auroral Polarization Stream)
Duskside
Region-2 FACs close
poleward across lowconductance ionosphere
AURORAL
OVAL
SAPS:
Strong poleward
Electric Fields are set up across
the sub-auroral ionosphere
SAPS
erodes the cold plasma
of the ionosphere and the outer
plasmasphere
LOW S
SAPS E FIELD
Coherent F-B returns
@ range < 1300 km
SAPS
PBL: SAPS & Ionospheric Trough
Radar Scan: Elevated TEC and Steep Gradients
[Foster, JGR, 1993]
Millstone Hill IS Radar
Discovery: Storm Enhanced Density
Geodetic Latitude
Electron Density at 500 km Altitude
noon
midnight
Universal Time 18-19 March 1990
Foster, JGR, 1993
Snapshots of the Plasmasphere Boundary Layer
Storm Enhanced Density (SED)
Mid-Latitude Ionosphere
Radar Scan
Composite picture of SED plume
(ISR & DMSP) lying at inner extent
of SAPS Channel
SED lies where equatorward extent
of SAPS overlaps plasmasphere field
lines
F-Region flux ~ E15 (m-2s-1)
Ion Flux is
Product of
Density times
Velocity
Log Ion Flux:
14 – 15 m-2 s-1
SAID
Ion Flux – Geospace Plasma Redistribution
GPS
TEC
Plasma Redistribution
TEC/Plasmasphere Plume
March 31, 2001
Magnetosphere-Ionosphere Coupling
Ground-Based GPS Maps
TEC Plume
[Foster et al., GRL 2002]
Radar
Flux
Direct Observation of Velocity
and Flux by Millstone Hill ISR
Plasmasphere / Ring Current Interactions
April 17, 2002
NASA IMAGE
SAPS Channel
Sun
(Merged image courtesy J. Goldstein)
Plasmasphere Erosion Plume
Sub-Auroral Ion Drifts (SAID):
Variability/Instability in the
Sub-Auroral Polarization Stream
s > 10-11 m-1
[Foster and Tetenbaum (1990, 1992)]
Subauroral Electric Field Experiments Using UHF F-B Coherent Scatter
[Sensitivity maps convolve beam pattern, magnetic field geometry, aspect sensitivity]
Fine scale probe of
E region electric
field dynamics
Scatter sensitivity all along
zero aspect line (in
antenna sidelobes)
Magnetic aspect
angle controls
scatter sensitivity
Geometry allows range to
lat/lon conversion
Strong scatter
appears in main
beam and sidelobes
Zero aspect scatter
goes to radar
horizon @ 1300 km
Main hotspot
Erickson et al, 2002
SAID: Instability in SAPS Channel
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Radar Bean Spans
SAPS Channel Equatorward
of Electron Precipitation
40 mV/m E-field Magnitude
Variability
~200 – 300 s periodicity
Enhanced Radar Backscatter (ERB) from Topside F Region
(Destabilization of Ion Acoustic Waves at PBL)
[Foster et al., GRL, 1988]
Mid-Latitude Topside
non-Thermal Backscatter
ERB associated with
Current Closure across
SAPS Channel
(Millstone Hill Azimuth Scan)
[Foster , 1988]
Plumes/Gradients Modify Radiation Belt WPI
SAPS
Discovery: Polar Tongue of Ionization (TOI)
[Foster et al., 1989]
Global Phenomenon:
Multi-Instrument
Observations Provide
Geophysical Context
and System Viewpoint
ISR Fields of View
Merged SuperDARN/DMSP Convection
Common projection: maglat/MLT @ 350 km alt
[Foster et al., JGR 2005]
Millstone Hill ISR
10x Enhancement of Topside
F-Region Density as SED
Traverses the Cusp
Feb 06, 1986 Millstone Hill
Nov 30, 2003 Millstone Hill
SED in the Cusp Creates a Strong Source of Ionospheric
Heavy Ions for Magnetosphere-Injection Processes
Coupling between the lower and upper atmosphere
•Recent studies show a strong
connection between the high-latitude
stratosphere (20-30 km above ground)
and low-latitude ionosphere (100-1000
km above ground)
•Ionospheric effects of SSW by
Millstone Hill ISR (Goncharenko and
Zhang, 2008), Jicamarca ISR (Chau et al.,
2009), GPS TEC (Goncharenko et al.,
2010)
•Selected as Focused Research Topic
for NASA 2012 LWS TR&T
“These new results have triggered an explosion of studies of mechanisms and types of possible
connections between terrestrial and space weather during SSW and other large-scale
perturbations in the lower atmosphere” – Wang et al., 2011
Temperature variations during SSW
Data: Millstone Hill ISR, 42oN
Model: TIMEGCM
You are
here
Goncharenko and Zhang, 2008
Liu and Roble, 2002
•Data: warming at 120-140km; cooling above ~150 km; 12-hour wave;
•First experimental evidence of alternating warming and cooling of upper
atmosphere
•Model: mesospheric cooling and secondary lower thermospheric
33
warming
PFISR, RISR & New Mid-Latitude SuperDARN Radars
Extend Global-Scale Ionospheric Coverage
2011
Aleutian
Islands, AK
2012
Azore Islands,
Portugal
OSU – 2010
Corvallis, OR
FHSU – 2009
Hays, KS
Large Field of View of Millstone Hill
Complements Multi-Instrument Regional DASI