Lake Level Monitoring Based on Satellite Altimetry
Jean-François Crétaux(1) , Muriel Bergé Nguyen(1) , Anny Cazenave(1) , and Alexei Kouraev(2)
14 Avenue Edouard Belin,
(2) LEGOS, 14 Avenue Edouard Belin, 31400 Toulouse, France
Accurate and continuous monitoring of lakes and inlands seas are available since 1991 thanks to the of satellite altimetry missions (Topex-Poseidon, GFO, Jason-1 and Envisat). Global processing of the data of these satellites could provide temporal and spatial times series of lakes surface height from 1993 to 2005 on the whole Earth with a sub-decimeter precision. The Legos laboratory is involved in this field of analysis since many years. The response of water level to regional hydrology is particularly marked for lakes and inland seas of semi-arid regions. Altimetry data can provide invaluable source of information in hydrology sciences, but in-situ data (rivers runoff, temperature, or precipitation) are still strongly needed to study the evolution of water mass balance of each lakes. Moreover, sea level variations that result from variation of hydrological parameters such as river discharge, precipitation and evaporation, are very sensitive indicators of regional climate variations.
Special focus on the Central Asian lakes will be presented, in particular which type of hydrological informations can be deduced from a combination of in-situ and altimetry data.