Enhanced Sea Ice Concentrations and Ice Extents from AMSR-E Data

Abstract

Much of what we know about the large scale characteristics of the sea ice cover has been inferred from results of analysis of passive microwave data, the latest of which comes from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E). AMSR-E has many advantages including higher resolution, wider spectral range and wider swath than historical data. This paper presents a review of techniques for sea ice concentration including the latest enhancements on the Bootstrap Algorithm for use with AMSR-E data. Validation studies confirms improvements in the accuracy after the enhancements depending on surface and atmospheric conditions. The improvements are also most apparent in winter along the coastal regions in the Antarctic where thin and young ice with little or no snow cover are abundant and the surface temperature of the ice can be much colder than the average. Improved characterization of the marginal ice zone leading to more accurate assessment of the ice edge is demonstrated. This in turn enables more accurate estimates of ice extent and ice area that are used to study seasonal and interannual variability of and trends in the sea ice cover. The AMSR-E extents and areas were used to evaluate and enhance historical passive microwave data for more accurate assessment of long term trends in the ice cover that may be associated with climate change. The AMSR-E data set is now regarded as the current baseline for the characterization of the sea ice cover because it provides the most accurate and comprehensive ice concentration data available.