青海南部冬季积雪和雪灾变化的特征

利用1961-2005年青海南部牧区气象台站观测的气温、降水、积雪资料，用气候诊断方法分析了该地区积雪等气候要素的年代际演变特征以及雪灾变化的成因。结果表明：20世纪60-90年代冬季青海南部牧区中雪和大雪出现的站次以及雪灾出现的站次有逐步增多的趋势，降雪量和地表平均积雪量每10 a分别增加1. 253 mm和8.246 cm，单站积雪量在海拔4100 m左右的高度上增加比较明显，其变化是由气候的年代际波动引起的。

Changes in Snow Covers and Snow Disasters in Winter in the South of Qinghai Province

Based on the data of air temperature,rainfall,and snow cover observed by meteorological stations in the pasturing area in the south of Qinghai Province from 1961 to 2005 and using the climate diagnosis method,the evolutional characteristics of climate elements and the cause of change of snow disasters are analyzed.The results indicate that the station-times for occurrences of moderate snow,heavy snow and snow disasters showed a gradually increasing tendency in the pasturing area in the south of Qinghai from the 1960s to 1990s,and the snowfall and mean surface snow cover climatologically increased by 1.253 mm/10a and 8.246 cm/10a,respectively.The snow cover of single-stations about 4100 m altitudes increased significantly.And such a change is closely related to the decadal oscillations of climate.