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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 6th Workshop., Hohenheim, Feb. 2007
AANNRR
First results from GPS tomography during the COPS field experiment
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?
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
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 [email protected].
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)
Exemple of Quicklooks available on the web site- IWV maps- IWV Time series
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
Three months of continuous water vapour measurements in Strasburg
The good day
First IASI / GPS Integrated water vapour inter comparison
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
The Gradients
The GPS tomography validation
What we to see:The famous dry air intrusions
P. Brosser
AVIONGPS
VOSGES
What we to see:Orographic circulations
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.
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 tomographieLimites de la tomographie
