中文摘要：

利用MODIS逐日无云积雪产品与AMSR-E雪水当量产品进行融合,获取了青藏高原500 m分辨率的高精度雪水当量产品,通过研究青藏高原积雪时空动态变化特征,分析了积雪覆盖日数、雪水当量以及总雪量的季节及年际变化.结果表明：青藏高原地区降雪主要集中在高海拔山区,而高原腹地降雪较少,降雪在空间上分布极为不均;2003-2010年期间,平均积雪日数呈显著减少趋势,稳定积雪区面积在逐渐扩大,常年积雪区面积在不断缩小.与积雪日数时空变化相比,雪水当量增加的区域与积雪日数增加的区域基本一致,但喜马拉雅山脉在积雪日数减少的情况下雪水当量却在逐年增加,表明该地区温度升高虽然导致部分常年积雪向季节性积雪过渡,但降雪量却在增加.总的积雪面积年际变化呈波动下降的趋势,但趋势不显著,且减少的比例很少.最大积雪面积呈现波动上升后下降的趋势,平均累积积雪总量呈明显的波动下降趋势,年递减率为1.0×10^3m^3·a^-1.

英文摘要：

In this study, the MODIS daily snow products without cloud contamination and AMSR-E snow water equivalent products were integrated to get snow water equivalent products of 500 m resolution in the Tibetan Plateau. Then these products were used to analyze the spatial-temporal changes of snow cover over the plateau during 2003 -2010. The results showed that snow had accumulated mainly in the high mountains, with a little in the hinterland of the plateau. The snowfall had showed a very unevenly distribution spatially. The average snow- covered days （SCD） had showed a significant decreasing trend, the stable snow cover area had increased and the perennial snow cover area had shrunk during 2003 - 2010. The increasing regions of snow water equivalent （SWE） was similar to those of SCD, but in the Himalayas. In the Himalayas, the SCD had decreased but the SWE had increased, which mainly caused by more snowfall in winter. The overall snow-covered area （SCA） had showed a fluctuating deceasing trend, but not so significant and the decreasing proportion was very small. In contrast, the maximum of SCA had showed an increasing trend during 2003 -2008 and then decreasing. The snow mass had showed a significant decreasing trend over the plateau during 2003 - 2010, with an annual decrea- sing rate of 1.0 × 10^3 m^3 a^-1.