中文摘要：

选取青藏高原东部地区1961-2010年64个测站的积雪数据，分析了冬季积雪日数的空间分布和年代际变化特征，结果表明：高原东部冬季积雪空间分布差异较大，巴颜喀拉山、唐古拉山和念青唐古拉山多雪且变率大，藏南谷地、川西干暖河谷地带及柴达木盆地少雪且变率小，这样的空间分布是由周边大气环流系统及复杂局地地形共同造成的；高原东部冬季积雪表现出“少一多一少”的年代际变化特征，分别在80年代末和20世纪末发生由少到多和由多到少的两次突变，尤其是20世纪末的突变更为显著；降雪和气温的变化是影响积雪日数的重要因素，其中降雪的影响更为显著；80年代末高原冬季降雪由少到多的突变是造成积雪日数发生相应变化的主要原因；20世纪末高原冬季气温和降雪分别发生由低到高和由多到少突变，其影响叠加导致积雪日数发生了更为显著的突变。

英文摘要：

By using the snow cover days data at 64 weather stations in the east of Qinghai-Tibet Plateau for the period 1961-2010 and the methods of REOF, polynomial fitting, running t-test, linear regression analysis, we analyzed spatial distributions and interdecadal variations of the snow cover days in winter. The results indicate the spatial distribution of the snow cover days in winter is far from uniformity. These regions, located in the Bayan Har Range, Tanggula Range and Nyainqentanggula Range, have rich snowfall and large interannual variability. These regions located in the valley of southern Tibetan Plateau, the dry-hot valley of western Sichuan Plateau and the Qaidam Basin have little snow and small interannual variability. The spatial distributions of the snow cover days in winter in the east of Qinghai-Tibet Plateau are jointly caused by the surrounding atmospheric circulation system and the local complicated terrain. By using polynomial fitting and running t-test methods, we found two abrupt interdecadal changes of winter snow in the east of Qinghai-Tibet Plateau. The first shift that changed from the stage of little snow to the stage of rich snow was observed at the end of the 1980s. The second shift that changed from the stage of rich snow to the stage of little snow occurred more significantly at the end of 20th century. By using linear regression method, we found that snowfall and air temperature in winter had a great effect on winter snow in the east of the plateau, especially the snowfall. The shift of winter snowfall that changed from the little stage to the rich stage at the end of the 1980s is the main cause for the corresponding change of winter snow. The common function about the shift of winter snowfall that changed from the rich stage to the little stage and winter air temperature that changed from the low stage to the high stage at the end of 20th century is the cause for the second shift of winter snow that occurred more significantly.