中文摘要：

海冰折射系数是一个重要的地球物理参数。利用Hong Approximation（HA）算法和星载辐射计AMSR-E数据,基于不同微波频段（6.9,10.7,23,37,89GHz）实现北极地区不同季节海冰折射系数反演。首先对反演所用关键数据海冰密集度反演算法的系点进行优化,反演结果与验证数据平均偏差分别为3.00%和-0.50%,低于其它常用算法。结果表明：冬季一年冰和夏季海冰的折射系数反演结果在所有微波频段的平均值范围为（1.78～1.75）和（1.72～1.70）,与前人研究结果基本一致,但冬季多年冰在较高频率的折射系数与前人结果偏差较大,高于10.7GHz的微波频段不能用于冬季多年冰折射系数的提取;综合利用不同波段海冰折射系数反演结果能够有效识别沿岸冰间湖（比如冬季6.9GHz）,区分多年冰与一年冰（冬季89GHz）,并能确定多夏季海冰边缘融化范围（夏季6.9GHz）。

英文摘要：

The refractive index of sea ice in the polar region is an important geophysical parameter. It is needed as a vital input for some numerical climate models and is helpful to classifying sea ice types. In the present study, according to Hong Approximation （HA）, we retrieved the arctic sea ice refractive index at 6.9, 10. 7, 23, 37, and 89 GHz in different arctic climatological conditions. The refractive indices of wintertime first year （FY） sea ice and summertime ice were derived with average values of 1.78~1.75 and 1. 724~ 1.70 at different frequencies respectively, which are consistent with previous studies. However, for multiyear （MY） ice, the results indicated relatively large bias between modeled results since 10. 7 GHz. At a higher frequency, there is larger MY ice refractive index difference. This bias is mainly attributed to the volume scattering effect on MY microwave radiation due to emergence of massive small empty cavities after the brine water in MY ice is discharged into sea. In addition, the retrieved sea ice refractive indices can be utilized to classify ice types （for example, the winter derivation at 89 GHz）, to identify coastal polynyas （winter retrieval at 6.9 GHz）, and to outline the areal extent of significantly melting marginal sea ice zone （MIZ） （summer result at 6.9 GHz）. The investigation of this study suggests an effective tool of passive microwave remote sensing in monitoring sea ice refractive index variability.