Intercomparisons of Antarctic sea ice types from visual ship, RADARSAT-1 SAR, Envisat ASAR, QuikSCAT, and AMSR-E satellite observations in the Bellingshausen Sea

Antarctic Sea Ice Processes and Climate (ASPeCt) visual ship-based observations were conducted in the Bellingshausen Sea during the Sea Ice Mass Balance in the Antarctic (SIMBA) cruise in austral spring 2007. A total of 59 ASPeCt observations are compared to coincident satellite active and passive microwave data. Envisat and RADARSAT-1 C-Band HH-polarization radar backscatter values (called NRCS henceforth) are derived on km-scales for six individual ice types and ice type mixtures. C-Band HH-polarized and Ku-Band VV-polarized NRCS are extracted on several 10 km-scale areas from coincident Envisat, RADARSAT-1, and QuikSCAT radar images for areas primarily covered with multiyear, deformed first-year, and undeformed young ice, as well as ice of the marginal ice zone (MIZ). The C-Band NRCS permits distinction between first-year, MIZ, and undeformed young ice. However, NRCS of the multiyear ice zone overlaps with that of the other ice zones and types. Ku-Band NRCS obtained for the same ice types permits discrimination of the first-year ice zone only. Obtained NRCS agree with those of previous studies and suggest a high degree of deformation and considerable potential for flooding for the first-year ice case. In comparison to large scale NRCS, AMSR-E snow depth values form two clearly separated clusters, one for 0.24–0.35 m depth (first-year ice zone) and one for 0.36–0.54 m depth (multiyear ice zone). However, a comparison to ASPeCt observations suggests a remarkable underestimation of the snow depth by AMSR-E in the multiyear–first-year-ice transition zone and for first-year cake ice. Nevertheless, a fusion of the coarse AMSR-E snow depth ranges for interior pack ice regions with radar imagery at large scale, appears promising for mapping the major zones (MIZ and Pack Ice) and ice types (first-year and multiyear) of Antarctic sea ice on a circumpolar basis.