In this paper, the latest Moderate Resolution Imaging Spectroradiometer (MODIS) eight-day Climate-Modeling Grid (CMG) snow cover data product MOD10C2 and 0. 05" resolution monthly mean fractional snow cover extent product MOD10CM from 2001-2011 were used to describe the temporal and spatial variation of snow cover by calculating its area over the Northern Hemisphere. We applied counted number of the weeks (CNW) with snow cover at each grid point for a season to quantitatively measure accumulation of the snow cover over this region. The results show that the tendency of snow cover area in the first twelve years of the 21st century is the same as that of the 20th century throughout the region,but different in several areas. In both periods,the snow cover area reduces in autumn and summer,and increases in winter. The areas sensitive to snow cover change for the period of 2001~2011 are different from those over the period of 1988 -1998 in that the western region of North America and the Mongolian plateau in these two periods are the abnormal change areas. The snow cover areas of the Qinghai-Tibet Plateau and the Alps in Europe from 2001~2011 do not change significantly,but the Turan Plain of the southern Kazakhstan and the northern coastal regions of the Caspian Sea experience abnormal change of snow cover areas in the 21st century.%利用最新发布的中分辨率成像光谱仪MODIS全球积雪8天合成数据MOD10C2和月合成数据MOD10CM,计算积雪面积及季累积积雪周数,分析北半球2001年～2011年积雪面积变化及时空分布特征.结果表明:北半球21世纪最初11年的积雪保持了20世纪的变化趋势,即积雪面积在秋夏两季减少而冬季增加,但在局部地区表现出新的变化特征,即积雪面积变化的异常区与1988年～1998年的有所差异:北美中西部和蒙古高原在两个时间段均是变化异常区,而青藏高原和欧洲阿尔卑斯山脉积雪在2001年～2011年变化不明显,哈萨克斯坦南部的图兰平原和里海北海岸地区是21世纪一个新的积雪变化异常区.
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