1. New Satellite Capabilities and Existing Opportunities Bill Kuo 1 and Chris Velden 2 1 National Center for Atmospheric Research 2 University of Wisconsin

2. GPS Occultation Basic measurement principle: Deduce atmospheric properties based on precise measurement of phase delay and amplitude.

3. Radiosonde Stations and Manufacturers Vaisala/Australia IM-MK3/India Shang/China MEISEI/Japan Mars/MRZ VIZ AIR Others From Junhong Wang

4. Quantifying Regional Differences n Calculate the mean absolute difference in refractivity between CHAMP and Radiosondes (N CR ) between 5 ~ 25 km. n Calculate the corresponding mean of the absolute value of the difference in refractivity between CHAMP and the ECMWF (N CE ) n Perform calculation using radiosonde data from different regions of the world from June 2001 to March 2004. From D.Rossiter (UCAR Summer Student)

5. Statistics of CHAMP - Radiosonde Comparison RegionSonde Type Average # of matches IndiaIM-MK3870.82/3.20.15/1.0 RussiaMars10030.30/1.30.09/0.9 JapanMEISEI1070.26/1.70.14/1.1 ChinaShanghai4020.19/1.40.15/1.0 AustraliaVaisala3660.18/1.30.13/0.9 Fractional Refractivity Differences between 5 ~ 25 km

6. CHAMP - radiosonde comparison India Australia

7. CHAMP - ECMWF Comparison India Australia

8. COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) 6 Satellites launched in early 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

9. COSMIC sounding distribution in a day

14. COSMIC Data Analysis n New GPS “Open Loop” (OL) tracking firmware was implemented and tested on SAC-C satellite n Initial OL results indicate: –Setting and Rising occultations are working –No more instrumental bias in the lower troposphere –>50% of soundings penetrate into lowest km n Additional improvements are possible and currently discussed with JPL First GPS rising occultation that was inverted at UCAR, with raw data provided by JPL

15. COSMIC GPS RO Soundings in 24 h over the Pacific

16. A Short Summary n COSMIC will be launched in early 2006, and will produce ~2,500 GPS RO soundings per day, uniformly distributed around the globe. COSMIC is expected to last for 5 years (2006 ~ 2011). n New signal tracking algorithm (open-loop tracking) has shown real promises for much improved soundings in the lower troposphere (remove negative bias, deep penetration). n GPS RO soundings have very high accuracy and very high vertical resolution (great for detecting upper level disturbances). n Loci of GPS RO soundings can be predicted two weeks in advance (very useful for experiment planning). n Many more missions are being planed beyond COSMIC. GPS RO technique is here to stay (so we better learn how to use the data effectively).

17. GPS radio occultation missions MissionLaunch-Duration# Soundings/dayRemarks GPS-MET4/1995 2+~125Proof of Concept CHAMP11/2000 ~5~250Improved receiver, tracking SAC-C11/2000 ~3~500Improved receiver, open loop tracking test GRACE5/2002 ~5~500RO data not yet available COSMIC3/2006 ~52500 - 3000Real time-ops RoadRunner USAF 11/2005 ~1+ (slated, Falcon LV) ~350Spacecraft in Test – waiting on rocket and next years fiscal dollars TerraSAR-X, German8/2006 ~5~400COSMIC RX & Antennas EQUARS Brazilian/Japanese ~ 2009 ~3~400COSMIC RX & CHAMP antennas, funding not yet secured by INPE, METOP5/2007 ~5~500Real time - ops COSMIC II3/2009 ~52500 - 3000Real time-ops. Ionosphere

18. o: EQUARS o: COSMIC Distribution of GPS Occultation events in 24 hrs with EQUARS (2009, inclination angle<20 o ) and COSMIC (2006, 6 LEO satellites at 72 o ) EQUARS Dense data rate in equatorial region COSMIC Global coverage, but less data at low latitudes +

19. Space - based GOS KALPANA (India) &