1. GPS Instrumentation Specification and Performance
John J. Braun
COSMIC Program
University Corporation for Atmospheric Research
Boulder, Colorado

2. Outline GPS Stations Operating for IHOP
Network Operation and Data Collection Percentage
Homestead Site
General Network Statistics
Data Products
Precipitable Water Vapor
Slant Water Vapor
Tomography Solutions

3. GPS Stations In IHOP Region
NOAA/FSL and DOT Stations
OU/ARM/SuomiNet Stations
Special Stations for IHOP
41 Stations Total
Map of Central United States. GPS stations used in IHOP are shown.

4. Acknowledgements CNRS - CNRM/GAME - France (contact: Joel Van Baelen)
NOAA Forecast Systems Laboratory (contact: Seth Gutman)
University of Oklahoma (contact: Randy Peppler)
ARM Program (contact: James Liljegren)
NASA/GSFC (contact: Dave Whiteman)

5. Homestead (SA14) Data Collection
Homestead GPS station data collection percentage. Generally, worked well - days133, 167, 173 are all short in time.

6. ARM CF (SG01) Data Collection
ARM CF SuomiNet station data collection percentage. First week or so, data not available, but after day 150 things worked ok.

7. French Station (BLAC) Data Collection

8. GPS Data Products Data Product Time Resolution Accuracy Location PW
30 Min
1.5 mm
Station Specific SW
2 Min
~1.5 mm
Tomography
15 Min
??? (g/m3)
ARM CF Region
Vital Specifications of PW Data

9. GPS PW and SW and Descriptions
PWV SW
SW is the integrated water vapor along single GPS ray paths
PWV is the average (estimate) of all SW observations in a cone scaled to zenith
Simultaneous observations along 8-12 GPS ray paths
GPS and WVR sensed SW and PWV agree to ~1.5 mm rms

10. Precipitable Water Vapor
Animated PW map of IHOP region

11. Slant Water Vapor
Homestead Slant Wate Vapor (right) on day when dryline formed and oscillated over Homestead site. Refractivity measurements from SPOL radar are shown on the left.

12. Example of SW During Storm
Example of polar sky plots of SW. Note the difference in azimuthal variability between the station in the clear air region and the station under the convective cell. Fifteen minutes of observations are plotted here.

13. International H20 Project Tomography Solution
Example skyplots of SWV during IHOP. The station under the clear sky has less azimuthal variability than the station under the convective cell.

14. Conclusions 41 GPS Stations in IHOP_2002 Region
Homestead station had high percentage of data availability
PW (30 min), SW (2 min), and Tomography Solutions Available
All GPS data are processed. PW data are available at JOSS web site. If someone is interested in SW and/or tomography data, they should contact me directly