利用静止卫星反演晴天和云天下行长波辐射的方法研究

项目名称： 利用静止卫星反演晴天和云天下行长波辐射的方法研究

项目编号： No.41301392

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 天文学、地球科学

项目作者： 余珊珊

作者单位： 中国科学院遥感与数字地球研究所

项目金额： 25万元

中文摘要： 为了获取时间连续的地表辐射数据，本项目以Meteosat静止卫星为数据源，开展下行长波辐射反演方法研究。利用大气辐射传输模型和典型大气数据库，构建具有较强适宜性的下行长波辐射反演模型。新的晴天模型通过引入地气温差来改进现有模型在干旱区白天产生的高估；云天模型考虑云的衰减、云底发射率等辐射项，从而改进低云时DLR高估的问题。为了获取云天长波辐射的关键参数，利用查找表技术，以及云垂直结构的统计信息，来提高云顶参数反演的效率和准确程度。最后在反演模型构建和云参数反演的基础上，结合静止卫星和大气再分析数据实现有云条件下的下行长波辐射估算。利用BSRN、ARM等站点的实测数据、以及现有的长波辐射产品对反演结果进行验证，并对验证结果进行深入探讨。

中文关键词： 长波辐射；有云天气；静止卫星；参数化模型；热红外

英文摘要： To obtain contiounus downwelling longwave radiation (DLR) for surface energy research, this study aims to develop an approach for retrieving DLRs from geostationary satellite (Meteosat-9) under all skies. The DLR parameterizations for clear and cloud skies are developed based on extensive radiative transfer simulation, also different atmospheric condition and cloud properties are considered in the simulation. The recent parameterizations always overestimate clear-sky DLRs in daytime over arid regions, and cloudy-sky DLRs when low cloud exists. To overcame these problems, the proposed parameterizations considered the difference between ground and air temperature in clear sky, and longwave radiation above cloud weaken by cloud in cloud sky. Cloud top parameters, the primary factors of cloud, are retrieved with from geostationary satellite, combining look-up table technology and cloud vertical stastical models. Based on the developed DLR algorithm and retrieved cloud parameters, the DLRs under cloudy skies are retrieved with the integration of Meteosat-9 and atmospheric reanalysis data. The DLRs are validated by the field measurements from the sites of Baseline surface radiation network (BSRN) and Atmospheric Radiation Measurement (ARM), and also compared with some longwave radiation datasets.

英文关键词： longwave radiation；cloudy sky；geostationary satellite；parameterization；thermal channel