1. Center for Atmospheric & Space Sciences
Data Assimilation, Infrastructure Issues, and International Collaboration
R.W. Schunk
Center for Atmospheric & Space Sciences
Utah State University
Logan, Utah 84322
DASI Workshop
June, 2004

2. Large Data Sets Require Data Assimilation Models to Maximize the Science

3. Global Assimilation of Ionospheric Measurements (GAIM) R. W. Schunk, L
Global Assimilation of Ionospheric Measurements (GAIM) R.W. Schunk, L. Scherliess, J.J. Sojka & D.C. Thompson
We use a physics-based ionosphere-plasmasphere-polar wind model as a basis for assimilating a diverse set of real-time (or near real-time) measurements. GAIM provides both specifications and forecasts on a global, regional, or local grid.
Global
Regional
Local

4. GAIM Assimilates Multiple Data Sources
Bottomside Ne Profiles from Ionosondes
In Situ DMSP Satellite Measurements
Ground-Based GPS TECs
TECs Between Ground Stations and Low-Earth-Orbiting Satellites With Radio Beacons
Satellite Occultation Data
Line-of-Sight UV Emissions from DoD Satellites
The Data Must be Real-Time or Near Real-Time.

5. Data Assimilated Exactly as They Are Measured
Bottomside Ne Profiles from Digisondes.
Slant TEC
Ne Along Satellite Tracks
Integrated UV Emissions
Etc.
Modular Construction.
Data Quality Algorithms Needed

6. GAIM Output Continuous Reconstruction of Global Ne Distribution
Ionosphere-Plasmasphere-Polar Wind
90-30,000 km
Quantitative Estimates of the Accuracy of Reconstruction
Auxiliary Parameters
NmF2, hmF2, NmE, hmE
Slant and vertical TEC
Model Drivers
High-Latitude Convection and Precipitation
Low-Latitude Electric Fields
Global Neutral Winds
Global Neutral Composition

7. Data Distribution
080/2002/00:30UT

8. Sample orbits tracks and occultation locations
IOX
SAC-C
CHAMP
Sample orbits tracks and occultation locations

9. Gauss-Markov Kalman Filter Example
November 16, 2003
GPS Ground TEC measurements from more than
900 GPS Receivers (from SOPAC Data Archive)
Includes Receivers from:
IGS
CORS
EUREF
and others

10. Gauss-Markov Kalman Filter Reconstruction
Climate
Kalman Filter
More than 3000 Slant
TEC Measurements
are assimilated every
15 minutes.

11. Reconstruction of the 3-D Ne Distribution

12. Are There Enough Data Available to Make Data Assimilation Useful?

13. NOAA CORS Data
• 332 Sites
• Dual-frequency Receivers
• Slant TEC

14. Japan GPS Receivers of the Earth Observation Network Dual-Frequency
1000 Receivers (25 km separation)
5000 Satellite-Receiver Paths Every 30 Seconds
12,000,000 Paths/Day
Slant TEC

15. SOPAC Online Map Interface

17. Operating Incoherent Scatter Radar Facilities
Jicamarca
Arecibo
Millstone Hill
Kharkov
Irkutsk
Sondrestrom
EISCAT - Tromso
EISCAT - Svalbard

18. Data Sources Ionosondes (>100 Stations)
Global GPS Network (>100 Receivers)
NOAA CORS GPS Network (400 Receivers)
Japan GPS Network (1000 Receivers)
SUOMI GPS Network (100 Receivers)
FAA-WAAS Network (24 Nodes)
2000 GPS Sites Worldwide (SOPAC Network)
DMSP Polar Satellites
C/NOFS Equatorial Satellite
TOPEX Ocean-Sensing Satellite
COSMIC Satellites (3000 Occultations/Day)
Geostationary High-Resolution Ionospheric Imagers
Magnetometer Network (>1000 Stations)
Incoherent Scatter Radar Network
SuperDARN Radars
Fabry-Perot Optical Network

19. DASI ISSUES
Many of the instrument arrays are spread around the world. The international community should participate in DASI. Funding is needed for a U.S. scientist to coordinate this effort.
Data assimilation models not only require data, but the data errors as well. International standards need to be established for ‘errors’ for each data type. Funding is needed for a U.S. scientist to coordinate this effort.
Funding is needed to develop and maintain data assimilation models.

20. Not all scientific studies require real-time measurements and many experimentalists will not be able to provide their data in real time. Therefore, two time windows should be considered ==>
Real-time
48 - hours