Seasonal Fluctuations of Water Storage in the Mekong River Basin from Satellite Altimetry, GRACE and other Remote Sensing data

We investigate the seasonal water storage over the Mekong basin using GRACE data over 2002-2004 which provides the total water storage (soil and underground waters plus surface waters). In parallel, we determine the seasonal variations of the surface water volume using 6 years (1998-2004) of SPOT/Vegetation imagery and Topex/Poseidon, ERS-2 and ENVISAT altimeter data. Surface water heights over seasonally inundated areas are measured using combined altimetry data from Topex/Poseidon, ERS-2 and ENVISAT. The seasonally varying extent of the inundated areas are derived from SPOT/Vegetation NDVI data. Over the common period of data (2002-2004), the surface water storage is subtracted to the total GRACE water storage to estimate the soil and underground water contributions. These results are compared with global/regional hydrological predictions. We also investigate the spatio-temporal response of each reservoir (surface, upper soil and underground water reservoirs) to seasonal precipitation forcing.