Recent developments in radar altimetry over land and applications to future altimetric missions

Satellite radar altimetry, which was initially designed for accurate measurements of sea surface height, has been demonstrated to be suitable for land surfaces as well. In this paper, a simplified expression of the flat surface impulse response (PFS), which enters in the computation of the radar Impulse Response (IR), has been found which is valid for a nadir pointing system as well as for small mis-pointing angles. On the basis of this model, simulations have been performed taking into account the system characteristics of the new sensor SIRAL (Cryosat-2), considered operating in LRM (Low Resolution Mode) varying some key parameters such as backscattering coefficient, off-nadir angle, surface RMS height in order to investigate the performance of the model itself. The outputs of the simulations show consistent and expected results in the various simulated scenarios. The simulated IRs were compared with real altimetric data from ENVISAT RA-2 and Cryosat-2 SIRAL for different types of targets such as Desert, Ocean, Ice.