the superdarn radar network and the rbsp...
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RBSP meeting, Sept. 2010
The SuperDARN Radar network and
the RBSP mission
Tim Yeoman
RBSP meeting, Sept. 2010
RBSP meeting, Sept. 2010
1. The SuperDARN network
2. Radar basics
3. SuperDARN data products
4. Operating modes
5. Radar scheduling and spacecraft coordination
6. SuperDARN and RBSP
The Super Dual Auroral Radar Network
(SuperDARN)
An international cooperation between 11 nations and numerous research groups running ~ 22 high latitude ionospheric radars
RBSP meeting, Sept. 2010
Northern hemisphere SuperDARN radars
1. The SuperDARN network
RBSP meeting, Sept. 2010
Southern hemisphere SuperDARN radars
1. The SuperDARN network
RBSP meeting, Sept. 2010
• A network of coherent radars
– sensitive to field aligned irregularities
• Operates in the frequency range 8 - 20 MHz - frequency is selected to:
– Allow refraction to make the radar wave vector to achieve orthogonality,
and
– Allow propagation conditions to get the signal to the area of interest
2. SuperDARN radar basics
RBSP meeting, Sept. 2010
Typical operations
involve 1 or 2, 7-
pulse sequences
2. SuperDARN radar basics
RBSP meeting, Sept. 2010
Pulse sequence is
transmitted
Sampling ends after
time appropriate to last
pulse and maximum
range
For each range of
interest:-
Auto-correlation is
carried out for all delays
available in the pulse
sequence
22 lags are computed to
generate an ACF
2. SuperDARN radar basics
RBSP meeting, Sept. 2010
Raw and fitted data
Fourier spectrum
Fitted spectrum
Complex ACF
ACF phase variation
2. SuperDARN radar basics
RBSP meeting, Sept. 2010
A SuperDARN summary
plot
Prime measurements
are:
Backscatter power,
Velocity,
Spectral width
3. SuperDARN data products
RBSP meeting, Sept. 2010
Location of
auroral zone –
particle deposition
Auroral zone
and polar cap
Joule heating
Ground scatter:
Ionospheric
Structure and
absorption, AGWs
and ULF waves
Meteor ablation /
Mesospheric winds
and tides
Sp
ec
tra
l w
idth
V
elo
cit
y B
ac
ks
ca
tte
r p
ow
er
3. SuperDARN data products
RBSP meeting, Sept. 2010
Line-of-sight measurements from
northern hemisphere radars
Northern hemisphere convection
pattern
derived using the “map-potential”
technique
The SuperDARN "map-
potential" technique(Ruohoniemi and Baker, 1998)
Chisham et al., 2007
3. SuperDARN data products
RBSP meeting, Sept. 2010
Grocott et al., 2009
Statistical analysis of
global convection keyed
to substorm phase
3. SuperDARN data
products
RBSP meeting, Sept. 2010
Amm et al., 2010Spherical elementary current
analysis for mesoscale structure
3. SuperDARN data products
RBSP meeting, Sept. 2010
Grocott et al., 2006
Field aligned current analysis
3. SuperDARN data products
RBSP meeting, Sept. 2010
Wright et al., 2004
Spectral width: a
diagnostic of overlying
magnetospheric
topology and wave
activity
3. SuperDARN data
products
RBSP meeting, Sept. 2010
3. SuperDARN data products
RBSP meeting, Sept. 2010
Chisham et al., 2007
Raw data sample
analysis
3. SuperDARN data products
RBSP meeting, Sept. 2010
4. SuperDARN operating modes
SuperDARN Operational flexibility
• Range resolution (45,30,15 km)
• Number of range gates
• Integration time (≥ 1 s)
• Lag to first range
• Scan mode
• Transmit frequency
• Plus much more in principle (stereo, alternative pulse
sequences, raw data sampling…)
RBSP meeting, Sept. 2010
The “stereo”
capability allows two
modes to be run
Simultaneously
Can be interleaved on a
mono radar with a loss of
time resolution
4. SuperDARN operating modes
4. SuperDARN operating modes
RBSP meeting, Sept. 2010
High vs standard
temporal
resolution data
4. SuperDARN operating modes
Yeoman
et al., 2010
Yeoman et al., 2010
4. SuperDARN operating modes
RBSP meeting, Sept. 2010
4. SuperDARN operating modes
RBSP meeting, Sept. 2010
4. SuperDARN operating modes
RBSP meeting, Sept. 2010
4. SuperDARN operating modes
RBSP meeting, Sept. 2010
4. SuperDARN operating modes
RBSP meeting, Sept. 2010
SuperDARN Operations scheduling
• Common time 50%
Standard radar scans on all SuperDARN radars
• Discretionary time 30%
Special modes on Individual radars
• Special time 20%
Special modes on all SuperDARN radars
• Spacecraft Special/Common time
Common agreed modes on all SuperDARN radars
5. SuperDARN scheduling and spacecraft coordination
RBSP meeting, Sept. 2010
Previous major SuperDARN/spacecraft coordinated
operations: scheduling and operation modes
Cluster2001 – 2007. ~10 days per month. 180 km to first gate, 75x45 km gates
All radars in the network sounding the same standard mode: 16 beams, 1 min
scans.
Aim: to ensure maximum network coverage of standard scans
Themis2007 – present. ~10 days per month. 180 km to first gate, 75x45 km gates
Mono radars sound 16 beams (2 min scans) with single interleaved beam (6s).
Stereo radars sound 16 beams Channel A (1 min scans), with single beam on
Channel B (3 s).
Aim: to ensure maximum network coverage of standard scans with added
high time resolution coverage
RBSPShould we be trying out “responsive scheduling” to catch storms?
5. SuperDARN scheduling and spacecraft coordination
RBSP meeting, Sept. 2010
The combination of RBSP and SuperDARN offer the opportunity of
studying the coupled inner magnetosphere and ionosphere-thermosphere
as a system.
Science examples:
• Direct comparision of magnetosphere pressure gradients (RBSP) and
field aligned and ionospheric currents (SuperDARN)
• Stormtime global convection and substorm electrodynamics
(SuperDARN) vs. in situ electric fields and particles (RBSP), X-rays
(BARREL)
• Storm effects in the ionosphere
• ULF wave activity and storms
Key SuperDARN data products:
Global electrodynamics, storm conditions, convection, cross polar cap
potential, location of OCFLB, mesoscale convection structures
6. SuperDARN and RBSP
RBSP meeting, Sept. 2010
•ULF wave activity and storms.
SuperDARN can measure ULF wave fields, frequency, ionospheric electric
field, azimuthal structure locally and globally. m up to ~100, (attenuation
factor of ~50 in ground magnetometer data) whilst RBSP measures
energetic particles and chorus waves.
Pc3-5 band (1000 - 10s): Direct measurement on a global scale from all
radars. Ionospheric and ground scatter can provide information (direct
measurement of electric field and Doppler shifts due to wave modulation of
the reflection height). Covered by existing THEMIS mode or similar.
ULF EMIC 10 - 0.2 s: Direct measurement at the lower end of the frequency
scale (all radars), Raw data analysis in the middle (partial array coverage),
spectral width broadening as a diagnostic at the upper end of frequency
scale (all radars).
VLF whistlers 100 Hz- 5 kHz no measurements from SuperDARN
6. SuperDARN and RBSP
RBSP meeting, Sept. 2010
What are the key SuperDARN measurements required by the RBSP
community, for radar operations planning?
• Storm quantification and alerts (together with magnetometers)?
• HF absorption as a low altitude precipitation indicator?
• Global convection response to storms, mesoscale convection?
ULF waves.
• Azimuthal structure?
• Integrated wave power in defined frequency bands?
• Global measurement or latitude/MLT distribution?
• Combined data products with ground magnetometer measurements?
6. SuperDARN and RBSP
RBSP meeting, Sept. 2010
The SuperDARN Radar network and
the RBSP mission
Tim Yeoman
RBSP meeting, Sept. 2010
• ULF waves generated by
interactions with energetic
particles within the Earth’s magnetosphere
Baddeley et al. (2004)
Wright & Yeoman (1999)
Powerful radio waves
from SPEAR modify
the upper
atmosphere.
This creates targets
for the CUTLASS
radar
Natural ULF waves
from space then
become visible
RBSP meeting, Sept. 2010
Wright et al., 2004
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