中文摘要：

利用1961年-2008年青海南部牧区地面气象观测资料、74个环流特征量和北半球500hPa高度场网格点资料，整理了地表积雪序列和雪灾年表，并对积雪、降水的变化趋势和雪灾发生的机理进行了研究。结果表明：1961年-2008年青海南部牧区春季共有25a发生积雪灾害，占总年数的52．1％。积雪量20世纪60年代和70年代为偏少期，80年代-90年代为偏多期，近8a维持在偏少阶段。当春季大西洋欧洲区极涡强度指数偏大、亚洲区极涡强度指数偏小、亚洲纬向环流指数偏小、印度副高脊线偏南、北半球500hPa高度场遥相关欧亚型（Eu）为正值时。高原高度场易偏低，青海南部牧区春季积雪容易偏多。反之，在上述关键因子相反的配合下，高原高度场易偏高，青海南部牧区春季积雪容易偏少。

英文摘要：

Based on meteorological data in southern pastoral areas of Qinghai Province during the period 1961-2008, 74 circulation characteristics and 500hPa height field gridded data of northern hemisphere, snow cover series and snow disaster chronology were obtained. Then, trends and mechanisms of snow disasters and precipitation were examined. Results show that there were 25 years during the study period in which snow disaster occurred in spring, which accounts for 52.1% of the total study years. In general, snow disaster was rare in the 1960s and 1970s, but became more in the 1980s and 1990s. Occurrence of snow disaster has remained less over the recent 8 years. It was found that when the Atlantic polar vortex index is larger in Europe and smaller in Asia, the Asian zonal circulation index is smaller, the India subtropical high ridge line is southerly, and the Northern Hemisphere 500hPa height field Europe-Asia teleconnection （EU） is positive, the height field in plateau is prone to decrease. Therefore, the accumulated snow increases in spring over the southern pastoral area of Qinghai Province. Otherwise, the height field tends to be high and the accumulated snow becomes less.