1
The FORMOSAT3/COSMIC MissionSpace Weather Application
AMS San Diego Jan. 11, 2005Christian Rocken [email protected]
2
Concept & Goals Constellation Observing System for Meteorology Ionosphere
and Climate (COSMIC) 6 satellites launched in 2005 Weather + Space Weather data Global observations of:
– Pressure, Temperature, Humidity– Refractivity, Bending– Ionospheric Electron Density, TEC
– Ionospheric Scintillation
Demonstrate quasi-operational GPS limb sounding with global coverage in near-real time
Demonstrate highly synergistic space weather observations from three payloads: GPS-OS, TIP, and TBB
Total project cost is ~$100 M, $80 M will be paid by NSPO in Taiwan, and $20 M will be funded by US agencies.
3
Mission science payloads
•High-resolution (1 Hz) absolute total electron content (TEC) to all GPS satellites in view at all times (useful for global ionospheric tomography and assimilation into space weather models)
•Occultation TEC and derived electron density profiles (1 Hz below the satellite altitude and 50 Hz below ~140 km), in-situ electron density
•Scintillation parameters for the GPS transmitter–LEO receiver links
•Data products available within 15 - 120 minutes of on-orbit collection
Tri-band Beacon (TBB)•Phase and amplitude of radio signals at 150, 400, and 1067 MHz transmitted from the COSMIC satellites and received by chains of ground receivers.•TEC between transmitter and receivers•Scintillation parameters for LEO transmitter - receiver links
Tiny Ionosphere Photometer (TIP)•Nadir intensity on the night-side (along the sub-satellite track) from radiative recombination emission at 1356 Å•Derived F layer peak density•Location and intensity of ionospheric anomalies (Auroral Oval)
GPS Occultation receiver
4
JOINT CERTO/TBB, GPS-GOX, TIP OPERATIONS ON COSMIC
From GPS Satellite
Ground Receivers
TIP EUV Field of View
5
COSMIC Status
6Figure: T. Yunck
7
Location of Profiles
1.5 months after launch
Final constellation
8
CHAMP Electron Density profiles
9
GPS and Langmuir Probe Comparison
10
GPS vs. Ionosonde Comparisons
Matches = 2183mean = 0.001 MHzstd = 0.81 MHz
Matches = 370mean = -9 kmstd = 39 km
11
COSMIC high resolution profiles
Area dominated by noise - used for noisecalibration of profile
Area affected by noise - profiles are noisy and/or affected by climatology
Highest quality profiles 5-30 km
Some profiles affected by boundary layer effects (super refraction)
Profile the (sporadic) ionosphericE-layer with ~1-km vertical resolution
12
Figure from the paper by Nishida et al., J. Met. Soc. Japan, 78(6), p.693, 2000.
RO provides best results between 8-10 and 25-30 km (effects of moistureand ionosphere are negligible). Is capable of resolving the structure of thetropopause and gravity waves above the tropopause.
13
Scintillation Sensing with COSMIC
No scintillationS4=0.005
ScintillationS4=0.113
GPS/MET SNR data
Where is the sourceRegion of the scintillation?
14
Localization of Irregularities
3000 4000 5000 6000 7000 8000 9000
X2-X (km)
-20
-10
0
10
20
Y (km)
3000 4000 5000 6000 7000 8000 9000-20
-10
0
10
20
Y (km)
-0.8 -0.4 0.0 0.4 0.8
B
C
Numerical Simulations 2 GPS/MET Occultations
15
Input
Data
CDAAC
NESDIS
GTS
NCEP
ECMWF
CWB
UKMO
Canada Met.
JMA
BUFR FilesWMO standard1 file / sounding
Getting COSMIC Results to Weather CentersThis system is currently under development by UCAR, NESDIS, + UKMOData available to weather centers within < 180 minutes of on-orbit collection
A similar system needs to be developed to deliver COSMICSpace Weather data to users!
16
GPS radio occultation missions
Mission Launch-Duration # Soundings/day Remarks
GPS-MET 4/1995 2+ ~125 Proof of Concept
CHAMP 11/2000 ~5 ~250 Improved receiver, tracking
SAC-C 11/2000 ~3 ~500 Improved receiver, open loop tracking test
GRACE 5/2002 ~5 ~500 Only few RO data available
ROAD RUNNER 6/2005 1-3 ~300 COSMIC receiver tests and risk reduction
COSMIC
FORMOSAT 3
9/2005 ~5 2500-3000 Real time-ops
TerraSAR-X 7/2005 ~5 ~400 COSMIC RX & Antennas
EQUARS 7/2006 ~3 ~400 COSMIC RX & Antennas
METOP 5/2007 ~5 ~500 Real time - ops
NPOESS 3/2011 ~10 ~500 May fly COSMIC II instead
17
18
Radio Beacon Receiver Chainsto Observe CERTO Beacons
UK
ARCTIC
Alaska
India
Taiwan
South America
Americas
South Africa
Ascension Kwajalein
Finland
Indonesia
Spain
Christmas
19
Orbit
Receiver
Irregularity
CERTO BeaconTransmissions
Antenna Orientation for Electron Density and Scintillation Region Tomography
20
TIP / GPS Occultation Concept
COSMIC
GPS Occultation Ray Path
TIP Line-of-Sight
COSMIC Orbit Track
21
22
CDAAC Processing Flow
LEO data Level 0--level 1
Orbits and clocks
Excess Phase(27 sec)
Can. Transf.Abel Inversion354 sec
1-D VarMoisture Correction23 sec
Fiducial data
Atmospheric processing
Excess Phase Abel InversionCombinationwith other data
Ionospheric processing
Profiles
Real time Task Scheduling Software
2 min
6.7 min
Current processing time for 35 occultations + 100 minutes of fid data: 9min
23
TIP Payload
TIP measures nighttime FUV emission of neutral atomic oxygen
TIP and GPS data can be processed together for improved ionospheric profiling
Radiative recombination: O++e- O+h– 135.6 nm produced by radiative recombination of O+ ions and
electrons– O+ and e- densities equal in the F-region – 135.6 emission intensity proportional to electron density
squared– Simple algorithm relates electron density to 135.6 nm intensity
measured by TIP Aurora: O+e- O +e- +h
– 135.6 nm produced in aurora through electron impact excitation
– TIP can determine auroral boundaries