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COSMIC: Constellation Observing System for Meteorology, Ionosphere and Climate

COSMIC: Constellation Observing System for Meteorology, Ionosphere and Climate. Status and Results with Emphasis on the Ionosphere Christian Rocken, Stig Syndergaard, Zhen Zeng UCAR COSMIC Project. FORMOSAT-3. Outline. COSMIC Introduction Results Some neutral Atmosphere Results Ionosphere

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COSMIC: Constellation Observing System for Meteorology, Ionosphere and Climate

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  1. COSMIC: Constellation Observing System for Meteorology, Ionosphere and Climate Status and Results with Emphasis on the Ionosphere Christian Rocken, Stig Syndergaard, Zhen Zeng UCAR COSMIC Project FORMOSAT-3

  2. Outline • COSMIC Introduction • Results • Some neutral Atmosphere Results • Ionosphere • GPS TEC Arcs • GPS Electron Density Profiles • Scintillation • Validation / Comparison to Models • TIP • TBB • Latency and Data Distribution • Summary

  3. COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) • 6 Satellites launched • 01:40 UTC 15 April 2006 • Three instruments: • GPS receiver, TIP, Tri-band beacon • Weather + Space Weather data • Global observations of: • Pressure, Temperature, Humidity • Refractivity • Ionospheric Electron Density • Ionospheric Scintillation • Demonstrate quasi-operational GPS limb sounding with global • coverage in near-real time • Climate Monitoring

  4. Tangent point The LEO tracks the GPS phase while the signal is occulted to determine the Doppler vGPS LEO vleo The velocity of GPS relative to LEO must be estimated to ~0.2 mm/sec (velocity of GPS is ~3 km/sec and velocity of LEO is ~7 km/sec) to determine precise temperature profiles

  5. Tangent point The LEO tracks the GPS phase while the signal is occulted to determine the Doppler vGPS LEO vleo The velocity of GPS relative to LEO must be estimated to ~0.2 mm/sec (20 ppb) to determine precise temperature profiles

  6. COSMIC Soundings in 1 Day COSMIC Radiosondes Sec 3, Page 10

  7. Atmospheric refractive index where is the light velocity in a vacuum and is the light velocity in the atmosphere Refractivity (1) (2) (3) • Hydrostatic dry (1) and wet (2) terms dominate below 70 km • Wet term (2) becomes important in the troposphere and can • constitute up to 30% of refractivity at the surface in the tropics • In the presence of water vapor, external information information is needed to obtain temperature and water vapor • Liquid water and aerosols are generally ignored • Ionospheric term (3) dominates above 70 km

  8. 6 Micro Satellites - USAF Minotaur Rocket Integration

  9. Launch on April 14, 2006, Vandenberg AFB, CA • All six satellites stacked and launched on a Minotaur rocket • Initial orbit altitude ~500 km; inclination ~72° • Will be maneuvered into six different orbital planes for optimal global coverage (at ~800 km altitude) • Satellites are in good health and providing data-up to 2200 soundings per day to NOAA COSMIC launch picture provided by Orbital Sciences Corporation

  10. COSMIC Current Constellation

  11. COSMIC - Final Deployment • 6 Planes • 71 Degrees inclination • 800 Km • 2500 Soundings per day • Latency 50-140 minutes from observation to NOAA

  12. Some Neutral Atmosphere Results

  13. 00:07 UTC 23 April 2006, eight days after launch Vertical profiles of “dry” temperature (black and red lines) from two independent receivers on separate COSMIC satellites (FM-1 and FM-4) at 00:07 UTC April 23, 2006, eight days after launch. The satellites were about 5 seconds apart, which corresponds to a distance separation at the tangent point of about 1.5 km. The latitude and longitude of the soundings are 20.4°S and 95.4°W.

  14. Comparison of Pairs of COSMIC soundings with GFS analysis

  15. Using COSMIC for Hurricane Ernesto Prediction With COSMIC Without COSMIC Results from Hui Liu, NCAR

  16. Using COSMIC for Hurricane Ernesto Prediction With COSMIC GOES Image GOES Image from Tim Schmitt, SSEC

  17. Southern Hemisphere Forecast Improvements from COSMIC Data Sean Healey, ECMWF

  18. Northern Hemisphere Forecast Improvements from COSMIC Data Sean Healey, ECMWF

  19. Space Weather

  20. 2 Antennas for orbits, TEC_pod (1-sec), EDP COSMIC s/c Vleo High-gain occultation antennas for atmospheric profiling (50 Hz) GPS Antennas on COSMIC Satellites Nadir

  21. Total electron content data (podTEC) • COSMIC generates 2500 - 3000 TEC arcs per day • Sampling rate is 1 -sec

  22. Absolute TEC processing • Correct Pseudorange for local multipath • Fix cycle slips and outliers in carrier phase data • Phase-to-pseudorange leveling • Differential code bias correction

  23. Satellite Multipath and Solar Panel Orientation P1 Multipath P2 Multipath

  24. Pseudorange multipath calibration

  25. Phase-to pseudorange leveling statistics

  26. COSMIC DCBs for ~ 1 year Quality of absolute TEC from COSMIC ~2 TECU

  27. Observed TEC Rays in 12-hour period

  28. … observed in Local time

  29. Latency of COSMIC podTec data

  30. Profile retrieval method TEC = solid - dashed [Schreiner et al., 1999] • Inverted via onion-peeling approach to obtain electron density N(r) • Assumption of spherical symmetry

  31. First collocated ionospheric profiles From presentation by Stig Syndergaard, UCAR/COSMIC

  32. Comparisons with ISR data[Lei et al., submitted to JGR 2007]

  33. Comparison of Ne(h) between COSMIC (red), Ionosondes (green)and TIEGCM (black) on Aug. 17 - 21nd COSMIC agree well with ionosonde obs, especially the HmF2; Vertical structures from COSMIC coincide well with TIEGCM in the mid-lat, but not in the tropics. TIEGCM shows a bit higher HmF2 compared with obs.

  34. From presentation by Ludger Scherliess, Utah State University Comparisons during quiet and disturbed Conditions COSMIC #2 GAIM Quiet COSMIC #2 GAIM Storm

  35. From presentation by Zhen Zeng, NCAR/HAO Comparison of NmF2 and HmF2 between COSMIC and GAIM during Apr. 21-28, 2006 Good agreement of NmF2 between COSMIC and GAIM; Higher peak heights from GAIM than those from COSMIC

  36. Using GAIM to correct for gradients From presentation by Stig Syndergaard, UCAR/COSMIC Courtesy of Zhen Zeng

  37. Scintillation Sensing with COSMIC No scintillation S4=0.005 Scintillation S4=0.113 Where is the source Region of the scintillation? GPS/MET SNR data

  38. Formosat-3/COSMIC Observations of Scintillations From presentation by Chin S. Lin, AFRL RED = COSMIC sat BLUE = GPS sat

  39. Observed TEC Rays in 12-hour period

  40. TIP 135.6-nm passes 14 Sep 2006FM1 FM3 FM6 0-24 UT (2100 LT) From presentation by Clayton Coker, NRL

  41. Chung-Li COSMIC TBB/CERTOTEC and Elevation Angle From presentation by Paul A. Bernhardt, NRL

  42. Getting COSMIC Results to Weather Centers Neutral Atmosphere Operational Processing TACC JCSDA NCEP Input Data NESDIS CDAAC ECMWF CWB GTS UKMO BUFR Files WMO standard 1 file / sounding JMA Canada Met. Science & Archive NRL Data available to weather centers within < 180 minutes of on-orbit collection

  43. Summary • COSMIC generates large amount of high quality space weather data • Data available for real-time (significant amount of data with less than 60 min latency) and for post-processing • Data are used for model comparison /improvement • Global scintillation data will be available within months

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