SEASAT SAR sea-ice imagery: summer melt to autumn freeze-up

Abstract

Some salient aspects of SEASAT L-band SAR sea-ice imagery are presented. High backscatter attributed to water-saturated surface layers reduces the ability to interpret ice conditions. Slush on water areas produces a strong backscatter which could be misinterpreted as rubble, but sequential imagery and floe sizes and shapes can be used to resolve this ambiguity. The slush effect may enhance the identification of active zones. Decreasing air temperatures during autumn freeze-up reduces background clutter increasing the ability to discern floe sizes and shapes. Higher SAR frequencies being considered for future satellites will show greater backscatter variations for different ice types, but many ambiguities will occur and the ability to discern ridges and floe sizes and shapes will be reduced in the marginal ice zones where interannual weather fluctuations will adversely affect surface scattering properties.