Lake studies from Satellite Altimetry

978-3-642-12795-3Accurate and continuous monitoring of lakes and inland seas has been possible since 1993 thanks to the success of satellite altimetry missions: TOPEX/POSEIDON (T/P), GFO, JASON-1, and ENVISAT. Global processing of the data of these satellites can provide time series of lake surface heights over the entire Earth at different temporal and spatial scales with a subdecimeter precision. Large lakes affect climate on a regional scale through albedo and evaporation. In some regions, highly ephemeral lakes provide information on extreme events such as severe droughts or floods. On the other hand, endorheic basin lakes are sensitive to changes in regional water balance. In a given region covered by a group of lakes, if the records of their level variations are long enough, they could reveal the recurrence of trends in a very reliable and accurate manner. Lakes are thought to have enough inertia to be considered as an excellent proxy for climate change. Moreover, during the last century, thousands of dams have been constructed along the big rivers worldwide, leading to the appearance of large reservoirs. This has several impacts on the basins affected by those constructions, as well as effects on global sea level rise. The response of water levels to regional hydrology is particularly marked for lakes and inland seas of semiarid regions. Altimetry data can provide a valuable source of information in hydrology sciences, but in-situ data (river runoff, water level, temperature, or precipitation) are still strongly needed to study the evolution of the water mass balance of each lake