利用海洋(HY-2)卫星微波辐射计数据反演北极区域海冰密集度

ARCTIC SEA ICE CONCENTRATION RETRIEVAL USING HY-2 RADIOMETER DATA

HY-2是中国自主研发的海洋卫星。本文研究了利用HY-2卫星微波扫描辐射计亮温数据反演北极海冰密集度的方法。参考NASA TEAM方法,我们对典型海区光谱梯度率和极化梯度率进行了统计分析,确定了计算海冰密集度所需的亮温特征值;利用天气滤波器有效去除了开阔海域由于大气中水蒸气、云中液态水、降雨等现象引起的海冰密集度计算错误。本文计算了2012年全年的北极海冰密集度产品,并对产品精度进行了初步验证,验证结果表明:三个海冰类型已知区域的海冰密集度结果与理想值比较接近,多年冰密集度的反演精度需要进一步提高。本文结果与美国冰雪数据中心和德国不来梅大学提供的两种业务化海冰密集度产品一致。本研究为利用HY-2卫星监测极区海冰密集度变化,发布实时产品奠定了基础。

The Chinese marine satellite（ HY-2） was successfully launched on 16 August 2011. We investigated an algorithm for sea ice concentration retrieval,based on brightness temperature data from the HY-2 scanning radiometer.In this study,the tie-points for brightness temperatures were selected based on statistical analysis of the polarization gradient ratio and the spectral gradient ratio over typical areas. The thresholds of two weather filters were determined to reduce the atmospheric effect over the open ocean. The total ice concentration over the Arctic in 2012 was calculated and compared with two existing operational data sets from the National Snow and Ice Data Center（ NSIDC） and the University of Bremen. The result of the comparison showed that the calculated sea ice concentration from the HY-2 radiometer data were comparable with ideal values from three typical ice regions in the Arctic Ocean. Our results were also in good agreement with two operational products. Our study demonstrated that HY-2scanning radiometer data and our retrieval algorithm adapted from the NASA algorithm could be used for operational sea ice services in the Arctic Ocean.