基于MODIS影像的昼夜地表温度反演研究

Research on Diurnal Surface Temperature Retrieval Based on MODIS Images

地表温度是研究区域地表能量平衡和资源环境变化的重要参数之一,为获取研究区的时空分布状况有重要的作用。对云南会泽县MODIS的昼夜两景影像数据进行辐射校正、定标等反演出地表温度图,通过31和32波段之间的波段运算显示出明显的地表温度空间差异和不同的地物类型;在已有的温度反演算法基础上,将地表温度数据引入到温度反演算法中,得出32波段反演的地表温度要高于31波段反演的地表温度,而且昼间两波段间的温度差要比夜间的两波段之间的温度差大,这是因为白天的可见光和近红外也存在辐射,而且白天的地表吸收温度比夜间高,辐射增大,导致白天的温差大于夜间的温差。利用地表实测温度数据与热红外遥感数据相结合,提高了研究区地表温度反演的精度,降低了反演难度。

The surface temperature is one of the important parameters of studying the regional surface energy balance as well as resources and environment changes, and it has an important role in obtaining the space - time distribution status of the study area. The surface temperature figures of Huize county in Yunnan province were retrieved through the radiation correction and calibration of data of the day and night two - scene MODIS images. The obvious spatial differences in the surface temperature and various types of surface features were shown by computing the band between band 31 and band 32. On the basis of the existing temperature retrieval algorithms, the surface temperature data were introduced into temperature retrieval algorithm, and it was obtained that： the surface temperature retrieved by band 32 was higher than that did by band 31, and the temperature difference between the two bands in the daytime was larger than that in the night, which were caused by higher surface absorption temperature and more visible - light and near - infrared radiation in the daytime. The combined application of the surface actual temperature data and the thermal infrared remote sensing data improved the precision of land surface temperature retrieval in the study area, and reduced the difficulty of the retrieval.