Assessment of EOS Aqua AMSR-E Sea Ice Concentration Using MODIS

Aqua Advanced Microwave Scanning Radiometer Earth Observing System for EOS (AMSR-E) Antarctic sea ice concentrations under winter conditions in 2006 are assessed using ice concentration data derived from Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) radiances. The AMSR-E sea ice concentrations are produced using the NASA Team 2 algorithm at a spatial resolution of 12.5 km, whereas the MODIS ice concentrations are derived from a broad-band albedo using a threshold technique at a spatial resolution of 500 m. There was generally good agreement between AMSR-E/MODIS ice concentrations for areas of first year ice, with the bias staying between -0.3% and -4.5%. For four of the five data sets studied, the vast majority of the AMSR-E pixels was greater than or equal to 80% first year ice, and resulted in a root mean square error (rms) ranging from 3.2% to 9.2% relative to MODIS. The fifth set of sea ice concentration data had about a -25% bias with a 30% rms error. Possible sources of error include unresolved cloud cover, the presence of new ice types, and flooded ice. Further comparative studies are needed to validate AMSR-E sea ice concentrations for other regions and seasons.