The experiment and validation of sea ice concentration AMSR-E retrieval algorithm in polar region

Abstract

Sea ice concentration is an important parameter for polar sea ice monitoring. Currently, the highest resolution microwave-detected sea ice concentration gridded product is provided by University of Bremen, which is derived by the Arctic Radiation and Turbulence Interaction Study (ARTSIST) Sea Ice (ASI) algorithm based on 89 GHz Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) data. For the purpose of providing the first generation Chinese sea ice remote sensing product for polar regions, we implemented a series of experiments including the interpolation algorithm, tie-points, and the weather filter based on the ASI algorithm for AMSR-E 89 GHz data. The main parameters, tie-points threshold value of pure ice (P 1) and pure water (P0) of ASI algorithm in the Arctic region were statistically analyzed throughout year 2009. The results showed that the yearly average value of P1 was 10.0 K, and that of P0 was 46.67 K in the pure ice and pure water typical regions of Arctic. The retrieved values of ice concentration is sensitive to P1 and P 0 when the differences of tie-points value are larger than 2 K. The effects of P1 and P0 on the ice concentration also changed for different P values. The calculation fomula was amended based on the statistic tie points. The sea ice concentration inversion fields in Arctic region of whole 2009 was obtained and compared with the products of University of Bremen. Furthermore, 12 cloud-free samples were selected from the visible band of Moderate-resolution Imaging Spectroradiometer (MODIS) image in Bering Sea and Chukchi Sea, and the derived sea ice concentration of MODIS data is averaged in the AMSR-E grid to validate the AMSR-E sea ice concentration. The comparisons of these samples showed that the error of our results is slightly less than that of University of Bremen's product with the spatial average error and spatial average absolute error of 3.84% and 10.83%, respectively.