Conjunctive Radar and Laser Altimetry Data Processing to Measure Snow Thickness

Sea ice is generally covered with snow. Information about snow thickness is essential to estimate sea-ice thickness from freeboard measurements and to model ocean-ice-atmosphere interactions. This paper discusses an algorithm to measure snow thickness by processing of coincident radar and the laser altimetry data. Radar return is dominated by the reflected signal from the snow-ice interface whereas laser return by the snow-air interface. Radar data are processed to obtain an accurate estimate of range to the snow-ice interface using aircraft trajectory derived from differential Global Positioning system (GPS) and Inertial Navigation System (INS). Laser data are processed to obtain range to the snow-air interface. The snow cover thickness is estimated from the difference in the radar and laser range estimates. The snow-thickness estimates obtained from radar and laser altimeter are comparing with the in situ snow thickness data collected over the Chukchi and Beufort lines.