青藏高原东部牧区大-暴雪过程及雪灾分布的基本特征

青藏高原东部牧区２６个台站在近三十年中共发生大－暴雪过程１６８９站次，按本文标准形成雪灾４１０站次。通过统计和诊断分析，揭示了大－暴雪过程及其雪灾的时空分布特征。结果表明：久治是大－暴雪过程和雪灾的频发中心，清水河是雪灾及成灾几率的高值中心；后冬成灾几率高达８０．３％，春季成灾几率仅１４．３％；大－暴雪过程次数和降水量线性增加势趋十分明显，导致雪灾危害日趋严重，９０年代进入雪灾的频发时期。

The basic characteristics of heavy snowstorm process and snow disaster distribution in eastern pastoral areas of Qinghai-Xizang Plateau

The 26 weather stations in eastern pastoral areas of Qinghai Xizang Plateau have appeared 1 689 heavy snowstorm weather processes in the past 30 years. In terms of our standard, snow disaster occurred 410 times totally. By means of statistic analysis, we concluded some preliminary time space distribution characteristics of heavy snowstorm processes and snow disaster. The results show that Jiuzhi was the frequent center of heavy snowstorm processes and snow disaster, while Qingshuihe was the high value center of snow disaster and disaster forming. The probability of disaster forming reached to 80.3% in the later winter, but only 14.3% in the spring. As a result, tomake an impact on snow disaster is getting more and more serious because of the significant increment of heavy snowstorm processes and precipitation, particularly, it becomes more frequent since 1990's.