Combined Measurement of Dongting Lake Level and Surface Extent Change
Wu, Geli; Elmi, Omid; Tourian, Mohammad; Sneeuw, Nico
University of Stuttgart, Institute of Geodesy, GERMANY
The technique of using satellite radar altimetry data to investigate the spatial and temporal variation of inland water bodies for hydrology purposes has been demonstrated in the past. At the same time, satellite SAR and optical imagery has been broadly used to monitor water surface extent. We here investigate the combination of these two spaceborne technologies for improved estimation of water volume changes and, hence, for a better characterization of the hydrological dynamics.
In this study, we select Dongting Lake (the second biggest freshwater lake in China), which is located across the Hunan and Hubei provincial border. It can be considered as key natural flood control and reduction element within the Yangtze middle basin. Dongting lake water level will be monitored through the Envisat and Jason data from June 2003 to December 2010. We analyze the waveforms of the altimetry data in order to improve the estimation of the water level fluctuations. We also calculate the surface extent changes observed over ASAR and optical imagery during the same time scale and identify the inundated area. The relationship between water extent and height is also analyzed.
Our approach to combine lake height and surface area allows the estimation of the water volume change over time. As such it represents a valuable geodetic contribution to quantify part of the hydrological cycle.