Estimation of river and lake heights from CryoSat-2 altimetry
Villadsen, Heidi; Andersen, Ole Baltazar; Stenseng, Lars

As result of global climate change floods and droughts are expected to become more frequent and more severe. It is therefore crucial to be able to monitor the changing water levels in rivers and lakes accurately; both purely for monitoring purposes but also in order to increase our ability to model future changes in land hydrology. So far, these reservoirs have been too small to resolve using satellite radar altimetry but with the introduction of the new high-resolution SRAL SAR altimeters, as carried on-board CryoSat-2 and soon Sentinel-3, it should be heavily improved. A state of the art estimate for these heights is already provided by the CryoSat-2 L2 GDR data from ESA. However, neither the satellite, nor the applied retracker have been developed specifically for inland water purposes, as such there is still room for improvement.

Supported by the recently funded EU 7th Framework LOTUS project, which focuses on the development of applications of Sentinel-3 for land and ocean monitoring for GMES, a customized retracker specifically for inland water purposes will be developed using the SAR altimeter data from CryoSat-2 until Sentinel-3 data are available.

Height estimations of rivers and lakes as given by ESA CryoSat-2 L2 dataset are evaluated and results using several empirical retrackers are presented to evaluate the potential of these new Cryosat-2 data for retrieval of heights on inland water bodies.