基于多光谱综合的MODIS数据云检测研究

云检测是卫星遥感数据处理中不可缺少的工作。通过分析云在不同波段中的大气辐射特点，结合MODIS数据的光谱特性，提出 一种多光谱综合的云检测方法。该算法从可见光反射率、红外波段亮温值以及亮温差等方面综合考虑，逐步建立一个云检测掩模。通 过对不同时期不同背景的MODIS数据进行验证和对比分析，结果表明，该模型的云检测效果理想，尤其对可见光波段难以识别的薄卷 云也有很好效果，为有效利用MODIS数据以及进行更加精确的反演提供可靠依据。

CLOUD DETECTION IN MODIS DATA BASED ON MULTI-SPECTRUM SYNTHESIS

Cloud detection is absolutely necessary in the processing of satellite remote sensing data.Through analyzing meteoric characteristics of cloud in different spectra and integrating the spectral characteristics of MODIS(Moderate Resolution Imaging Spectroradiometer),the authors put forward a new cloud detection method based on multi-spectrum synthesis.Taking into account such factors as visible reflectance,infrared brightness temperature and window brightness temperature difference,the algorithm can gradually build a cloud detection mask and finally obtain an entire cloud processing result which can discriminate cloud from clear sky.The algorithm was applied in different periods and different scenes to make validation and analysis.The results show that the cloud detection is ideal,especially for thin cirrus which is invisible in the visible band.This technique can promote the use of MODIS data and improve the accuracy of retrieving.