海冰密集度是极区海冰监测的重要参数,目前分辨率最高的微波海冰密集度产品为德国Bremen大学发布的针对AMSR-E 89 GHz频段数据利用ASI算法反演的网格数据。为实现中国极区遥感产品从无到有的战略步骤,本文针对AMSR-E 89GHz频段微波数据的ASI算法,进行了插值算法、系点值和天气滤波器一系列试验。针对北极海区,着重对影响反演结果的主要参数——纯冰和纯水的亮温极化差异阈值,即系点值(P₁和P₀)进行了2009年全年的统计分析。研究表明,2009年北极纯冰和纯水的代表区域P₁和P₀年平均值分别为10.0 K和46.67 K;2 K以上的系点值差异引起的海冰密集度差别较为显著;同样的系点值差异在不同极化差异P取值范围对海冰密集度的影响也不同。通过统计确定的系点值推算并修正了海冰密集度反演公式,对2009年全年北极海冰密集度进行了反演,并与Bremen大学产品进行了比较。继而对白令海和楚科奇海12个晴空下MODIS可见光样本数据进行反演,以验证AMSR-E冰密集度反演结果,并对误差原因进行了分析。本研究反演结果与MODIS样本比对的误差略小于Bremen大学的反演产品,空间平均误差为3.84%,空间平均绝对误差10.83%。

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 (P₁) 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 P₀ 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.