1. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 GPS Atmosphere Sounding J. Wickert, G. Dick, G. Gendt, M.Ramatschi, and M. Rothacher GeoForschungsZentrum Potsdam

2. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 From „Errors“ to signals GPS receivers at the ground and aboard satellites Atmospheric excess phase (optical phase length) Bending angle

3. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 Ground based sounding

4. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 Result: Zenith Path Delay (ZPD) (with mm accuracy) PWV = Π (T m ) ZWD ZHD = f (Press) [±1 mm accuracy] ZPD = ZHD + ZWD dry, hydrostatic wet Additional data: pressure and temperature at the station Additional parameter: gradients (North-South, East-West); new: slants Θ isotropic water vapor distribution & known 'mapping'-Function (~1/sin Θ) Ground based GPS

5. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 GPS ground networks Global (Analysis of ~ 180 stations at GFZ)

6. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 GPS ground networks Regional densified (e.g., Germany, ~250 stations in near-real time)

7. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 Comparison of GPS-IWV with WVR, RS and LM at Potsdam/Lindenberg

8. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 Satellite based sounding

9. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 CHAMP (since 2000) GRACE (since 2002) TerraSAR-X (launch 2006/7) Metop (launch June 30, 2006) COSMIC (6; launch April 14, 2006) GPS aboard satellites for occultations

10. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 Vertical structure of the atmosphere Global, very precise, high vertical resolution All-weather, calibration free

11. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 National NRT occultation project Continuous provision and usage of NRT RO data together with weather prediction centers ECMWF, DWD and Metoffice Goals: provision of NRT RO data (~2h latency assimilation to NWP (impact studies) real assimilation to NWP planned other user are invited to use NRT data

12. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 Our contribution to COPS/GOP

13. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 GPS ground stations for COPS/GOP ~60-70 stations in the region Integrated WVP (IWV) slants Near-real time provision (30- 45 min delay) 15 min resolution in time 1-2 mm accuracy

14. GPS Atmosphere Sounding, COPS/GOP, April 10, 2006 + 5 additional GPS ground stations Dry room Power supply Internet (optional) Shoke ring antenna Receiver+laptop