Hydrologie spatiale :Développement d'applications pour l'utilisation de la télédétection sur les grands bassins fluviaux

Abstract : Remote sensing can be considered as an important tool for studying the variations of water masses in large river basins due to a homogeneous sampling both in space and time. The objective of this PhD thesis was to develop new hydrological applications using measurements acquired by various types of satellite mission: radar altimetry, satellite imagery, gravimetry from space. Space altimetry is commonly used to study time variations of water level of large rivers, lakes and flooded zones. New hydrological products such as hydrological profiles or river slopes. Levelled limnimetric networks can thus be defined, with gauge stations on the rivers as well as on the flooded zones. Used in combination with imagery from space, satellite altimetry can be used to determine surface water volume variations in large river basins. These parameters are fundamental for hydrologists because hydrological profiles are necessary for hydrodynamic studies and distribution of water volume variations constrains the distribution of water masses between flooded zones and hydrographic network. Examples of use of these techniques are presented for the Amazon and the Mekong basins. In March 2002, a new generation of gravity missions was launched: the Gravity Recovery and Climate Experiment (GRACE) space mission. The objective of GRACE is to measure spatio-temporal variations of the gravity field with an unprecedented resolution and precision, over time scales ranging from a few months to several years. As gravity is an integral of mass, these spatio-temporal gravity variations represent horizontal mass redistributions only to the extent they are assumed to be caused by surface water changes. On time scales from months to decades, mass redistribution mainly occurs inside the surface fluid envelopes (oceans, atmosphere, ice caps, continental reservoirs) and is related to climate variability. An analysis of the evolution of water and snow mass is presented using the first monthly geoids from the GRACE mission, at global and regional scales, as well as the estimation of evapotranspiration rate at basin scale. These results are compared with surface water volume variations previously obtained for the Mekong basin.
Document type :
Theses
Other. Université Paul Sabatier - Toulouse III, 2005. French


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Submitted on : Tuesday, June 20, 2006 - 2:18:22 PM
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Frédéric Frappart. Hydrologie spatiale :Développement d'applications pour l'utilisation de la télédétection sur les grands bassins fluviaux. Other. Université Paul Sabatier - Toulouse III, 2005. French. <tel-00080744>

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