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基于MODIS资料反演海上能见度的经验模型
Empirical Models for Retrieval of Atmospheric Horizontal Visibility over the Sea Based on MODIS Data

作  者: ; ; ; ; ; ;

机构地区: 广州地理研究所

出  处: 《中国海洋大学学报(自然科学版)》 2006年第3期355-360,共6页

摘  要: 利用2002年10月~2003年8月的中分辨率成像光谱数据MODIS(Moderate Resolution Imaging Spectroradiometer)和华南沿海及海上能见度观测数据,对华南海域连续的、长时间序列的能见度遥感监测和定量反演进行了试验。将MODIS影像分为:晴空(Ⅰ);雾和低云(Ⅱ);有降水积云(Ⅲ)和其它(Ⅳ)4类,并按照通道间相关性最小和与大气水平能见度相关最大的原则进行通道筛选。初步分析表明,水平能见度确实与MODIS卫星表观反照率存在一定的函数关系。在此基础上,对每一类进行通道筛选和特征因子提取,建立分类的反演经验模型进行大气水平能见度的遥感反演。并与观测结果进行了比较。结果表明,在Ⅰ和Ⅲ类大气状况条件下,能见度的反演结果较好(相关系数分别达到0.6和0.9,远大于95%信度检验水平),而大气状况较为复杂的Ⅱ类反演精度较低,相关系数只有0.5(仅达94.2%显著性检验水平)。由此可见,对于海上下垫面均一、而大气状况复杂的遥感反演问题,根据大气状况分类简化的统计反演是较为有效的1种方法。同时,对大气的辐射消光特性的了解和MODIS通道特性的分析,也是决定反演结果的重要因素。 In this article, the correlation between MODIS (Moderate Resolution Imaging Spectroradiometer) speetral data and atmospheric horizontal visibility (AHV) was analyzed over the South China coastal area during October 2002 to August 2003. Firstly the MODIS images were classified into four categories, which are: clear sky (Ⅰ), fog and lower layer cloud (Ⅱ), cumulonimbus (Ⅲ), and the rest (Ⅳ). Then the optimal bands were selected to minimize correlated bands and maximize their correlation coefficients to MHV. Statistic analysis showed that certain relationship did exist between visibility and surface reflectance of MODIS. Situations Ⅰ and Ⅲ achieved better results (correlation coefficient above 0.6 and 0.9, exceeding 95 % confidence level), which is because of their relatively fixed atmospheric composition and simple extinction process. While Category Ⅱ is a more complex atmospheric condition and thus results in relatively low retrieval precision, with correlation coefficient 0.5 and 94.2 % confidence level. Finally categorized regression models were built and simulated results were compared to real observations. Therefore, the classified statistical retrieval model based on atmospheric conditions is an effective method for AHV retrieval problem.

关 键 词: 大气水平能见度 气溶胶 成像光谱 遥感反演

领  域: [天文地球] [天文地球]

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