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Potentiel de la mesure GPS sol pour l'étude des pluies intenses méditerranéennes.

Abstract : The Cévennes-Vivarais and the surrounding area up to the Mediterranean has been chosen by the OHM-CV (Mediterranean Hydrometeorological Observatory of the Cévennes-Vivarais) for the frequence and representativity of the intense rainfalls that affect this area. Since 2002, autumnal campaigns of GPS measurements have taken place there to try to improve our understanding of the tropospheric water vapor field which is associated with the intenses rainfalls. GPS meteorological observations are ZTD (Zenith Total tropospheric Delay) and gradients of delays. Expressed by an East-West component (Gew) and a North-South component (Gns), the gradient of delay shows the anisotropy of the water vapor field around GPS site.For the analysis of GPS observations of permanent and temporary networks of the OHM-CV region, an optimal configuration has been researched considering different sensitivity tests. An accuracy of 5 mm can be obtained for ZTD, 6 mm for Gew and 12 mm for Gns. Gns is less precise than Gew because no satellites fly over the North pole.In order to prepare the assimilation of the GPS observations via a Météo-France mesoscale data-assimilation system (ALADIN and AROME -- Météo-France's future operational model), GPS observations (ZTD, STD and gradients) simulators have been implemented in a non-hydrostatic high resolution model called Méso-NH. The digital laboratory, which the model Méso-NH constitutes, has been an effective means of quantifying the sensitivity of delays simulations at different formulations of atmospheric refractivity.
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https://tel.archives-ouvertes.fr/tel-00012085
Contributor : Hugues Brenot <>
Submitted on : Wednesday, October 18, 2006 - 5:21:44 PM
Last modification on : Thursday, November 19, 2020 - 3:54:27 PM
Long-term archiving on: : Friday, November 25, 2016 - 12:13:08 PM

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  • HAL Id : tel-00012085, version 2

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Hugues Brenot. Potentiel de la mesure GPS sol pour l'étude des pluies intenses méditerranéennes.. Océan, Atmosphère. Université Joseph-Fourier - Grenoble I, 2006. Français. ⟨tel-00012085v2⟩

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