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1.
Radio Occultation Data Analysis at the COSMIC Data Analysis & Archival Center (CDAAC)
2. Overview
COSMIC Description
CDAAC data processing and data formats
Successes
Challenges
CDAAC 'Live' demo
3. COSMIC at a Glance
4. COSMIC Launch
5. COSMIC Occultation Distribution
6. COSMIC System
7. COSMIC Spacecraft Orbital Science’s ORBCOM s/c bus
Mass ~ 70 kg, Size ~ 1m diameter
Propulsion: orbit insertion, maintenance, de-orbiting
Attitude:
Control: 2deg pitch, 5deg roll/yaw (2-sigma)
Knowledge: 1deg pitch, 2deg roll/yaw
Nadir orientation, 3-axis stabilized
40 MB on-orbit storage
8. COSMIC Payloads Each COSMIC satellite will carry 3 complementary payloads
GPS - for atmospheric/ionospheric profiling and scintillation
JPL Heritage design
Tiny Ionospheric Photometer (TIP) for F2 layer electron density mapping
NRL Heritage design
Tri-band beacon (CERTO/TBB) for high-resolution ionospheric imaging and scintillation studies
NRL Heritage design
9. COSMIC GPS Receiver: ARGO
10. COSMIC Data Analysis and Archival Center (CDAAC)
11. CDAAC Responsibilities Process all COSMIC observations
LEO/GPS orbit determination
Atmospheric & Ionospheric profiles
Rapid analysis for operational demonstration
Post-processed analysis for climate and other research
Provide data to universities and research laboratories
Provide data feeds (< 3hr) to operational centers
Archive data & provide web interface
12. CDAAC Processing Flow
13. GPS Data Processing
14. LEO POD Quality
15. Calibration of excess phase delay
16. Inversion Details
17. CDAAC Hardware
18. CDAAC Software Software written in perl, C or FORTRAN
Currently consists of around 100 separate packages:
CVS modules for source developed at UCAR
open source packages:
apache
postgres
perl
perl modules
Commercial packages
Bernese
F90 compiler
Includes install system for easy compilation and testing on a basic Linux system
19. CDAAC post processing
20. CDAAC real-time processing
21. Realtime processing (cont.)
22. Question: How to deliver data
23. File Formats
24. BUFR format
25. BUFR format issues
26. Successes
27. Validation Statistics with NCEP
28. ROSE Refractivity Comparisons
29. Tailored experiments with predicted occultations
30. COSMIC Challenges
31. Inversion Q/C: CHAMP 2002.213-243
32. Clock distribution problems
33. L2 signal noise, SAC-C
34. Extrapolation of Ionospheric Correction to process occultations with noisy L2
35. Super-refraction, Ducting
36. Summary COSMIC program on track for 2005 launch: satellites are built at Orbital, GPS at Broad Reach, TIB + Beacon at NRL
CHAMP and SAC-C processing up-to-date
Near-real time processing, ~1 day latency for CHAMP data
~ 70-80% of calibrated occultations are inverted successfully (2002.213-243)
Good agreement between CHAMP and SAC-C
Good agreement with NCEP/ECMWF
Comparisons between GFZ/JPL/UCAR successful
Ongoing work on data delivery to weather centers (formats, protocols)
Web page: www.comic.ucar.edu