中文摘要：

针对积雪遥感监测中常用的二值分类算法误差较大的问题,根据青藏高原的地理环境特征,并在考虑地表覆盖的情况下,以MODIS数据作为数据源、TM/ETM＋数据作为＂真值＂影像,选用7个不同雪盖子区建立了青藏高原MODIS像元雪盖率与雪盖指数之间的线性关系模型,并用其它4个雪盖子区对模型的稳定性和精度进行分析。结果表明：该方法能有效的提取青藏高原MODIS亚像元尺度的积雪信息,反演结果与MO-DIS/NASA雪产品数据相比,精度得到明显改善。

英文摘要：

The traditional algorithm of snow cover remote sensing monitoring was a binary classification.Large error can be expected when using moderate to coarse resolution imagery to map snow covered areas at a regional scale.The objective of this study is to develop a sub-pixel snow mapping algorithm for Qinghai-Tibet Plateau using MODIS data.Using Landsat 30-m observations as ＂ground truth＂,the percentage of snow cover was calculated for 500-m cells.Then based on the characters of geographic environment in Qinghai-Tibet Plateau and considering different land cover types,a regression relationship between 500-m NDSI observations and fractional snow cover was developed over seven different snow covered regions and tested over other areas.This study indicated that the fraction of snow cover within a MODIS pixel of Qinghai-Tibet Plateau can be estimated by the algorithm effectively,and it enhanced the accuracy obviously in contrast to MODIS/NASA standard snow cover product.