利用MODIS数据判识祁连山区积雪方法研究

Method for Discriminating Snow in Qilian Mountain Region Based on MODIS Data

对祁连山区积雪、云和各种下垫面进行光谱分析,利用2003年7月至2005年3月的MODIS数据资料,在前人所做研究工作的基础上提出利用归一化差值积雪指数NDSI(Normalized Difference Snow Index)和中分辨率成像光谱仪(Moderate Resolution Imagigng Spectroradiometer)的band 18和band31的结合,采用逐步逼近法去除大部分云、盐湖、冰面、沙漠、戈壁等对积雪判识的干扰,从而判识出祁连山区积雪。由结果分析和检验显示,利用本文方法可以比较有效识别出祁连山区积雪。

By analyzing spectrum characteristics of snow, clouds and different land covers in the Qilian Mountain region based on MODIS data from July 2003 to March 2005, a new method for snow discrimination is presented on the basis of former researches, which combined NDSI （Normalized Difference Snow Index） and hand 18, band 31 of MODIS to discriminate snow from clouds, saline, ice, desert, etc. with a step - by - step approach. Both result analysis and examination show that snow in the Qilian Mountain region can be effectively discriminated by the method of this article.