近44年青藏高原东部积雪的年代际变化特征及其与降雪和气温的关系

选取青藏高原东部地区1967~2010年61个测站的积雪数据,分析比较了整年和不同季节高原积雪的年代际变化特征及其与降雪和气温的关系,结果表明:除了秋季以外,高原东部积雪表现出“少雪-多雪-少雪“的显著年代际变化特征,80年代末发生的由少到多突变仅在冬季积雪中表现显著,20世纪末发生的由多到少突变在冬春两季积雪中均表现显著;降雪和气温的变化是影响高原东部积雪的重要因素,降雪变化的影响更加显著,尤其是秋季降雪;在冬春季降雪偏多时段,降雪的变化主导着积雪的变化;在冬春季降雪偏少时段,气温变化的影响增大,某些时段会超过降雪,甚至达到主导积雪变化的程度。

Interdecadal Variations of Snow Cover and Their Relations with Snowfall and Air Temperature over East of Qinghai-Tibetan Plateau in Last 44 Years

By using the data set with snow in 61 weather stations at east of Qinghai-Tibetan Plateau for the period from 1967 to 2010 and these methods of polynomial fitting,linear trend fitting,running t-test,correlation analysis,multiple regression analysis,we analyzed the interdecadal variations of snow cover and their relations with air temperature and snowfall over east of Qinghai-Tibetan Plateau. The result shows snow cover in winter and spring at east of Qinghai-Tibetan Plateau have the obvious characteristics of interdecadal change,little before the middle stages of the 1980 s,rich from the later stages of the 1980s to the later stages of the 1990 s,little again after the end of 20 th century. Snow cover in autumn at east of Qinghai-Tibetan Plateau show weak reduction linear trend. The shift of snow cover changing from less to more around 1987 only happened in winter. The shift of snow cover changing from more to less around 1997 significantly happened in winter and spring.The variations of snowfall and air temperature are the important factors on snow cover at east of Qinghai-Tibetan Plateau. The influence of snowfall is more important,especially in autumn. In the period of rich snowfall in winter or spring,the variations of snowfall dominates the variations of snow cover. In the period of poor snowfall in winter or spring,the effect of air temperature increase obviously,sometime it will be more powerful than snowfall,even to the extent of dominating the variations of snow cover at east of Qinghai-Tibetan Plateau.