中文摘要：

选取青藏高原局部地区为研究对象,针对MODIS逐日积雪覆盖率产品（MOD10A1）存在精度差、地域限制等问题,利用MODIS地表反射率产品（MOD09GA）,提出了分段建模的方法,生成了精度更高的积雪覆盖率产品,并采用Landsat资料对该产品进行了验证。结果表明：①MOD10A1标准积雪覆盖率产品在青藏高原地区精度较低,提取的平均雪盖率为29.16%,与同时相TM影像的积雪覆盖比例（22.45%）相差较大,两者相关系数仅为0.74;②利用MOD09GA地表反射率产品重建积雪覆盖率的分段模型,提取的平均雪盖率为21.70%,与同时相TM影像的积雪覆盖比例较为接近,且两者相关系数达到0.85;③与TM资料生成的积雪真值图像对比,改进后的分段模型标准误差与绝对平均误差都优于标准产品,对研究区积雪覆盖面积监测精度的提高有一定的改善。

英文摘要：

With the development of remote sensing（RS） technology,the RS data have become as the indispensable materials in dynamic monitoring of snow cover,and they play an important role in monitoring snow coverage and analyzing snow disasters.In this paper,the snow coverage retrieved from Landsat TM was taken as the ground truth,the fractional snow coverage（FRA） retrieved from MOD10A1 was validated using Landsat TM image,and an improved segmentation model was proposed for retrieving the FRA by using the MODIS ground reflectivity products（MOD09GA） in some parts of the Qinghai-Tibet Plateau.The results are as follows： ① The average snow coverage retrieved from MOD10A1-FRA was 29.16% in our study,but it was 22.45% in TM,and the correlation coefficient of FRA between those two datasets was 0.74;② The FRA model improved with the MOD09GA product had much better accuracy in SCA acquisition,the average retrieved snow coverage was 21.70%,and the correlation coefficient was 0.85;③ Compared with the ＂ground truth＂,the performance of both the standard error of the improved fractional model and the mean absolute error was better than the MOD10A1/FRA product,which could be used to improve the accuracy of monitoring snow coverage in the study area.