1. C. Champollion (1,2), C. Flamant (2), F. Masson (3), P. Gégout (3), P. Brousseau (4), G. Dick (5), J-Van Baelen (6) and E. Richard (7 ) (1) Géosciences Montpellier UM2/CNRS, (2) Service d'Aéronomie UPMC/IPSL, (3) Institut de Physique du Globe de Strasbourg EOST/CNRS, (4) Centre National de Recherches Météorologiques Météo-France/CNRS, (5) GeoForschungsZentrum Potsdam, (6) Laboratoire de Météorologie Dynamique OPGC/CNRS, (7) Laboratoire d'Aérologie OMP/CNRS COPS 6 th Workshop., Hohenheim, Feb. 2007 ANRANRANRANR First results from GPS tomography during the COPS field experiment

2. Why GPS measurements ? 1- Additional data with good temporal sampling for CI case studies 2- Impact of GPS data assimilation in numerical modeling: need to determine the best GPS network configuration for future operational applications 3- Synergy between the GPS tomography and the profiling instruments (RS, LIDAR,IASI)‏ 4- Real interest of the GPS tomography: - Quantitative evaluation of the GPS tomography accuracy - Are they new information in GPS tomography inversion compared to numerical simulation with GPS data assimilated?

3. The COSP GPS Network A few numbers: - 25 GPS (20 Fr. et 5 All.) installed during COPS - ~80 GPS on a large COPS area - A regional network (50 km)‏ - A E-W dense profil (10 km)‏ - 3 months of continuous measurements - About 15 people participated to the field experiment

4. What has been done - A complete raw data base have done. Concerning the French GPS stations, only 3 have experienced technical problems (power supply). - A near real time (H+90) GPS data processing (ZTD) have been done and published on the web (P. Gégout; EOST / IPGS): eost.u-strasbg.fr/COPS (web site still active with new reprocessed data). - A rapid post-processing have been done to provide quicklooks of non real-time data. - Definitive GPS data post-processing (ZTD and IWV) available at cedric.champollion@gm.univ-montp2.fr.

5. What will be done (and when?)‏ - Slant delay processing and Tomographic inversion (until the end of March)‏ - Slant delay processing and cross-validation with GFZ results. - Validation of the IWV and the tomographic inversion with the help of RS and LIDAR measurements (IPSL / GM)‏ - Studies of the water vapour temporal variability near the Bruche Valley (and diurnal cycle) (IPGS / IPSL / GM)‏ - Participation in CI case studies (IPSL / MF)‏ - Assimilation of ZTD (IPSL / MF)‏ - Evaluation of the accuracy of NRT GPS data processing (IPGS / GM)‏

6. Exemple of Quicklooks available on the web site - IWV maps - IWV Time series

7. Meteorological GPS Measurements: The troposphere is modelled by two variables: - Integrated Water Vapour - Gradients NS and EW: azimuthal water vapour variations Meteorological GPS Measurements: The troposphere is modelled by two variables: - Integrated Water Vapour - Gradients NS and EW: azimuthal water vapour variations

8. Three months of continuous water vapour measurements in Strasburg

9. The good day First IASI / GPS Integrated water vapour inter comparison

10. Meteorological GPS Measurements: The troposphere is modelled by two variables: - Integrated Water Vapour - Gradients NS and EW: azimuthal water vapour variations Meteorological GPS Measurements: The troposphere is modelled by two variables: - Integrated Water Vapour - Gradients NS and EW: azimuthal water vapour variations

11. The Gradients

13. The GPS tomography validation

14. What we to see: The famous dry air intrusions P. Brosser

15. AVION GPS VOSGES What we to see: Orographic circulations

16. Thanks to the: GPS INSU division Secretaries of SA and IPGS Field participants (Diana, Sophie, Myrto, Karen, Frederic, Phillipe, Joel, Pascal, Cécile, Caroline, Bernard,...). GPS data providers: Orphéon, RGP, GFZ, Engref de Nancy, SwissTopo Meteorological data providers: Météo-France, SwissMeteo, DWD, SAFIRE GM and GA for free GPS rent.

17. Solution: assimilation de radiosondages Solution: assimilation de radiosondages - Taille de la cellule horizontale et verticale imposée par la densité du réseau GPS - Résolution verticale limitée par la géométrie du problème Limites de la tomographie