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 cedric.champollion@gm.univ-montp2.fr.

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