The Purposes of
Synoptic Observations
Synoptic Network Workshop, Boulder, April 2013
Oskar von der Lühe
Kiepenheuer-Institut für Sonnenphysik, Freiburg
Synoptic observations have a long
tradition
Sunspot drawings by Galileo from 1613 (Rice Galileo Project)
• The first modern solar physicist: Galileo proposed the solar origin of
sunspots
What are synoptic solar observations?
• Time-resolved measurements of a physical characteristic
of the Sun
– with a scope of the entire solar disk and the solar space
environment
– with a scope of long time periods
– often with high cadence (minutes)
• Similar paradigms – repeated measurements of large
volumes of targeted and untargeted astrophysical
quantities with long duration and high cadence - now
enter nighttime astronomy where they are called “time
domain astrophysics” and create billion-$ projects
ADS KW search: (sun | solar) & synoptic
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Examples of synoptic observations
NSO/GONG
Udaipur
H
Intensity
2012/02/14
GONG, MDI, AIA,
MSFC, SOLIS, LASCO,
PMOD, SWPC
Role of contemporary solar physics
• Distinct field of research since the introduction of stellar
spectroscopy in the 19th century
– Leading stellar spectroscopy for many decades, still leading in
polarimetry
– Leading in theoretical understanding of stellar atmospheres
– Only discipline in astrophysics which has direct impact on modern
civilization
• The “Easy Experiments” have mostly already been done
• Big steps of discovery and understanding of the Sun which result from
simple experiments require new technologies
• Nobel Prize level discoveries are not likely
• Progress means hard and tedious work
– Advanced technology, techniques and methods in theoretical and
experimental solar physics
Role of contemporary solar physics
Stellar
Physics
(non-stellar)
Astrophysics
Stellar dynamos
Stellar structure
Exoplanets
Cosmic magnetic fields
Abundances
Solar Physics
Particle physics
General relativity
Fundamental
Physics
Flares and CMEs
Solar „constant“
Terrestrial
Physics
Role of contemporary solar physics –
relation to stellar physics
• Stellar physics has reached a
similar level of maturity as
has solar physics
• Currently active links are
stellar magnetic activity and
asteroseismology
• Stellar physics has
experienced a tremendous
boost since the discovery of
exoplanets
• Advances in Stellar physics
reflect back on Solar physics
C. Schrijver / LMSARL
Role of contemporary solar physics –
solar-terrestrial relations
• Monitoring of solar activity and
energetic events is essential for
spacecraft operations
• Impact of solar activity on the
Earth‘s magnetic field may impact
large infrastructures
• Predicting solar activity, solar
energetic events and their impact
in Earth is the bread-and-butter
raison d'être for solar research
Stereo A
WSA-Enlil (NOAA)
Solar Physics in the 21st Century –
scientific questions
• How is the solar magnetic field generated, maintained and
dissipated?
–
–
–
–
Discriminate solar dynamo models
Determine the role of induction effects near the surface for the global field
Determine the characteristics of angular momentum transport inside the Sun
Observe, identify and characterize magnetic reconnection
• How does solar magnetism influence the internal structure and the
luminosity of the Sun?
– Compare the Sun with stars with differ in magnetic activity through
asteroseismology
– Determine impact on exoplanet detection and characterization
• How are the solar corona and the solar wind maintained and what
determines their properties?
– Observe, identify and characterize acoustic and magneto-acoustic waves in
the upper atmosphere
• What triggers transient energetic events?
– Determine the role of the interaction of interior flow and magnetic fields
– Establish reliable space weather prediction
Which observing capabilities are needed to
address current and future science questions?
• Detailed studies of magnetic field and plasma physics processes in the solar
atmosphere including the corona
Several
largetemporal
aperture
telescopes
– Consistently
highest spatial,
and spectral
resolution
and in space
– High sensitivity,on
verythe
highground
SNR
– Modest fields of view and temporal coverage
– Access to a large part of the electromagnetic spectrum
• Comprehensive studies of large to medium scale processes in the solar
interior and atmosphere including the corona
Small to
medium
aperture
ground
based
– Medium/high
spatial
resolution,
limited spectral
resolution
and/or
coverage, selected
spectral lines
networks
and space facilities
– Full solar disk, entire electromagnetic spectrum
– Long term uninterrupted temporal coverage
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Why do we need large solar telescopes?
Numerical simulation (M. Rempel, HAO)
Observations with GREGOR (v. d. Lühe, KIS)
New Large Solar Telescopes
BBSO New Solar
Telescope
1.6m USA
Yunnan Obs. Solar
Telescope
1m China
Advanced
Technology Solar
Telescope
European Solar
Telescope
Gregor
4m EUR
1.5m D/ES
National Large
Solar Telescope
2m India
4m USA
Design Construction
Commissioning
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Purposes of synoptic observations
• How is the solar magnetic field generated, maintained and
dissipated?
–
–
–
–
Discriminate solar dynamo models
Determine the role of induction effects near the surface for the global field
Determine the characteristics of angular momentum transport inside the Sun
Observe, identify and characterize magnetic reconnection
• How does solar magnetism influence the internal structure and the
luminosity of the Sun?
– Compare the Sun with stars with differ in magnetic activity through
asteroseismology
– Determine impact on exoplanet detection and characterization
• How are the solar corona and the solar wind maintained and what
determines their properties?
– Observe, identify and characterize acoustic and magneto-acoustic waves in
the upper atmosphere
• What triggers transient energetic events?
– Determine the role of the interaction of interior flow and magnetic fields
– Establish reliable space weather prediction
Synoptic facilities - Space
• Space missions offer
unique
opportunities
– Access to the entire e.
m. spectrum
– Absence of
detrimental impact of
the Earth‘s
atmosphere
– Stable conditions and
very consistent data
SoHO
Stereo
Hinode
Solar Dynamics Observatory
Solar facilities - Ground
• Ground based
observatories offer
unique opportunities:
– Large telescopes and
instruments
– Flexibility
– High data rates
GREGOR/KIS
Synoptic facilities – Space vs. Ground
• There is no synoptic measurement
which cannot in principle be done from
space
– many measurements can only be done
from space
• Limiting factors for space missions are
cost and telemetry
– ground missions are required to get the
complete picture
• Solar physics has a fair share of space
missions
• Scientific goals and data products of
space and ground missions must
complement and be well aligned
Solar Dynamics Observatory
– Redundancy is part of that
PMOD/WRC
Solar observing facilities - Ground
Synoptic Realm
Networks for helioseismology
and space weather prediction
GONG
BiSON
SOON
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Solar Physics in the 21st Century –
Synoptic networks
• Future solar networks should provide:
– Velocity maps at different heights
– Maps of vector magnetic fields at different heights
– Maps of quantities relevant for space weather
– At multiple wavelengths
– With high cadence, duty cycle and lifetime
– With high sensitivity to velocity and magnetic fields
– Complement space missions
Solar Physics in the 21st Century –
Synoptic networks
• Operating even a small network (BISON, GONG)
is a big effort for a national community
• Designing, deploying and operating a
distributed, comprehensive, ground based
network requires a new level of international
collaboration
– SOLARNET - SPRING
• Opportunity to involve and sustain smaller
research groups in solar physics
What else do we need?
Data management and archiving
• Synoptic facilities on the ground and in space
produce large amounts of data which must be
digested to produce useful products
• Procedures for data calibration, reduction and
archiving are similar, if not the same
– MDI and GONG share a lot of data reduction
procedures
• Space projects come with data management
funding
• Ground facilities share these needs and also
require adequate funding
What now are the purposes of
synoptic observations?
• Solar physics is relevant because of its societal
impact
• Synoptic solar observations are essential for
answering relevant key questions
– Both space and ground facilities are indispensible.
They must be complementary
– Future ground based networks should be an
international endeavor
• The importance of synoptic observations is veiled
by the visibility of large projects which has
adverse effects on funding