Simulation of ASIRAS Altimeter Echoes for Snow-Covered First-Year Sea Ice

We have developed a simulator for the European Space Agency´s Airborne SAR/Interferometric Radar Altimeter System (ASIRAS) altimeter echoes from snow-covered first-year sea ice. The simulated echoes are used to investigate how measurements are affected by the snow and ice characteristics. Our simulations show that when the snow cover is dry, the echo from the upper ice surface typically dominates. The simulated echoes prove to be very sensitive to the presence of liquid water in snow and the small-scale roughness of the ice surface. The accurate estimation of the ice freeboard is likely possible only under dry snow conditions and when the snow load is known. The ASIRAS simulator concept can also be used for the CryoSat altimeter.