Water Level Change in the Mekong Region
Buchhaupt, Chris¹; Fenoglio-Marc, Luciana¹; Prigent, Catherine²; Becker, Matthias^1
1Institute of Geodesy, Technische Universität Darmstadt, GERMANY; ²Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique, CNRS, Observatoire de Paris, FRANCE

The Mekong Delta is one of the most productive agricultural areas in the world. The Mekong basin has a total cachment area of about 800,000 km2, its delta is a fertile alluvial region. The potential for sea level increases and extreme floodings due to global warming makes the Delta a place where local, regional, and global environmental changes are converging. This very flat region is referred as the Mekong lowlands.

We analyse changes in the water level in the river observed by the altimeter satellite Envisat in 2002-2010 and estimate monthly surface water volume change over successive years (2002-2007) by combining the surface water extent data set with altimetric observations over the Mekong river delta.

The surface water extent is evaluated at 25 km sampling intervals over fifteen years (1993-2007). The multisatellite methodology captures, at the global scale, the extent of episodic and seasonal inundations, wetlands, rivers, lakes, and irrigated agriculture, using passive (SSM/I) and active (ERS scatterometer) microwaves and visible and near�]IR (AVHRR) observations.

The river water level time-series used are obtained from the Hydroweb and River-Lake databases and constructed from the altimetry GDR data and SGDR altimeter waveforms retracked using dedicated retrackers.

Seasonal and interannual variability in river and total water change is compared to the water level change in the area derived from the GRACE gravity mission and simulated by the hydrology model WaterGAP2.