The global remote sensing of lakes, wetlands and rivers for hydrological and climate research

Remote sensing, particularly the use of radar altimeters and imaging radiometers, offers a global perspective for some hydrological parameters. Satellite radar altimetry with its all-weather operation can be used to derive lake, river and wetland levels and infrared imagery can be used to derive lake and wetland areas. These remote sensing measurements can be applied to several programmes including the determination of regional scale hydrological variability and in the proxy monitoring of precipitation changes. A remote sensing programme at the Mullard Space Science Laboratory (MSSL) thus aims to monitor globally and continually all large inland water bodies. Level time series, derived from the current TOPEX/POSEIDON altimeter mission are presented here for the Caspian Sea, the Sudd wetlands and the Amazon River. The accuracy of these level variations is ~5 cm rms