1. Formosat3 / COSMIC: Constellation Observing System for Meteorology, Ionosphere and Climate
Mission Status and Data Distribution
Unidata Policy Committee Meeting 29 Oct. 2007
COSMIC is called Formosat-3 in taiwan. Taiwan’s NSPO is the primary sponsor (80%) and mission operator of COSMIC.

2. Current Constellation Oct. 28, 2007

3. The LEO tracks the GPS phase
while the signal is occulted to determine the Doppler
LEO
vleo
vGPS
Tangent point
The velocity of GPS relative to LEO must be estimated to ~0.2 mm/sec (20 ppb) to determine precise temperature profiles
… so once the orbits have been determined well it is possible to determine atmospheric profiles.
The lower right panel on this slide shows a birds-eye view of the CHAMP satellite in LEO. The white line indicates the ray to the GPS which is not shown and the while dot shows the location of the tangent point introduced in the top left panel.
As the tangent point descends through the atmosphere the temperature profile is shown in the little panel to the right of the globe.
The temperature profiles is obtained in post processing.

4. Evolving COSMIC Constellation
Temperature [C] at 100 mb (16km)

5. Comparison of collocated Profiles
Fig. 7a: Vertical profiles of “dry” temperature (blue and red lines) from two independent receivers on separate COSMIC satellites (FM-3 and FM-4) on 3 August, The satellites were approximately 5 seconds apart, which corresponds to a distance separation at the ray tangent point of about 1 km. The latitude and longitude of the soundings are 21.8°S and 32.9°W. The black line (GFS) is the NCEP analysis of temperature interpolated to the time and location of the COSMIC soundings.

6. Animation of COSMIC determined water vapor at 1 km altitude for several months

7. Statistical comparison of FM3-FM4 Soundings separation < 10 km
0.2% precision between km
Difference for pairs of GPS RO measurements (FM3-FM4) with tangent point separation less than 10 km. The blue line shows the number of pairs of nearby soundings with height. The red line shows the mean difference, and the green lines show the standard deviations of the differences plotted around the mean.
The RMS difference of refractivity between 10 and 20 km altitude is less than 0.2%,
Schreiner et al. 2007

8. Detection Of Boundary Layer With RO
Figure 5. Examples of COSMIC RO-retrieved bending angle and refractivity profiles in the sub-tropics, showing sharp ABL top (bending angle is a function of ray tangent height) compared to ECMWF analyses.

9. ABL Height Observations During COSMIC Year 1
(bending angle gradient > 1e-2 rad/dH, height < 3 km)

10. Leading Weather Center Newsletters

12. Using COSMIC for Hurricane Ernesto Prediction
With COSMIC
Without COSMIC
Effect of assimilation of COSMIC data on Hurricane prediction. Left with COSMIC, right w/o COSMIC. Integrated cloud liquid from model output is shown in grey shades.
Results from Hui Liu, NCAR

13. Using COSMIC for Hurricane Ernesto Prediction
With COSMIC
GOES Image
.. . And now compreed to the GOES image of the same storm
GOES Image from Tim Schmitt, SSEC

14. 6-Year RO Temperature Anomaly Trend Tropics, 200 mb (~12 km)

15. Preliminary 2002 - 2007 RO Temperature Trends (12, 17, 21, 27 km)
Ramaswamy, V., M-L. Chanin, J, Angell, J. Barnett, D. Seidel, M. Gelman, P. Keckhut, Y. Koshlekov, K. Labitzke, J-J. Lin, A. O'Neill, J. Nash, W. Randel, R. Rood, K. Shine, M. Shiotani, and R. Swinbank, Stratospheric temperature trends: Observations and model simulations, Reviews of Geophysics, 39, (2001).
The large cooling in polar regions may be related to large variability in this region.
Chanin et al., 2001: 0.75 C/decade cooling in km NH
QBO not removed (significant for 6 years)
Need to add slope uncertainties

16. Number of Profiles (Oct. 28, 2007)
752,000 Neutral Atmosphere
1,006,000 Ionosphere

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

18. Processing Center Status
30 TB downloaded
( Gbytes/day)
80% of soundings delivered in < 3 hours
All data post-processed with CDAAC 2.0 software (until June 2007)
New firmware currently tested at JPL

19. 619 data users from 42 countries are registered
COSMIC Data Access
619 data users from 42 countries are registered
* Select the 'Sign Up ' link under
COSMIC
Accept data use agreement
* Enter information:
Name, Address, , user_id,
Password, planned use of data
An will be sent within 2-3
business days to indicate
access has been granted.
COSMIC data are open to public, and freely available.
Use of COSMIC data requires registration-a simple process.
More than 350 users have registered as of November 1, 2006.

20. COSMIC Data Availability
Data opened up to public in July 2006
All Data (including raw data) available at the end of each day
Real-time products (profiles of bending, refractivity, …) in WMO standard format available via the GTS
Post-processed data for climate research will be updated every few months
Data use agreement with NSPO required for use of all data and data products (via TACC or CDAAC website)

21. COSMIC Data Policy
Real-time data (raw data, excess phase data, etc.) available upon approval of letter request to NSPO director and UCAR president
All requests have been approved
Data policy must be revised for distribution of near-real-time data products to Unidata community
Users should still register

22. Summary
Deployment to final constellation almost complete (raising FM1)
Large amount of high quality data resulted in:
600+ registered data users
~80% of soundings penetrate to lowest km of atmosphere
Operational use by world’s leading weather centers
Demonstration of 0.2% precision of RO observation in km height range
Extened climate record
Remote sensing of global ABL / Convection
Improvements to ionospheric models
Global scintillation observations
COSMIC presently faces several difficulties
Frequent unexplained drops in SNRs from GPS antennas
Lost 1 solar panel on FM2
Stuck solar array drive on FM3
No communications presently with FM6
Chances for a Follow - on mission would benefit from wider user community