青藏高原1979—2007年间的积雪变化

利用雪深被动微波遥感数据产品,对青藏高原1979—2007年积雪深度、积雪日数的分布变化及其趋势进行了分析。结果表明:青藏高原积雪日数、积雪深度和海拔三者之间在空间上具有显著正相关;青藏高原积雪在1988年发生突变,该年前后积雪分布有显著不同,这与20世纪80年代中后期青藏高原由暖干时期进入暖湿时期有关;将青藏高原按夏季水汽来源不同将其分为南北两部分,发现29年来北部积雪日数变化与全国积雪变化相反呈极显著增加趋势(R2=0.39,P0.01),以1.40 d/a的趋势增加,主要原因是西北部地区冬季积雪日数增加;南部积雪深度与全国积雪变化一致呈极显著减少趋势(R2=0.24,P0.01),以-0.04 cm/a的趋势减少,主要原因是东南部春、夏、秋三季积雪深度减少。

The analysis of snow information from 1979 to 2007 in Qinghai-Tibetan Plateau

In this paper, we used long-term (1979-2007) snow depth dataset of China, which was provided by ''Environmental and Ecological Science Data Center for West China'' and analyzed the change of snow depth and distribution on the Qinghai-Tibetan Plateau. The linear regression method was used to study the variation trends of mean snow cover days and snow depth on annual-scale and seasonal-scale. Results show that, first, there were significant positive relationship between either two of the mean annual snow cover days, the mean annual snow depth and elevation. Second, the snow distribution on the Qinghai-Tibet Plateau had a mutation in 1988. Before 1988 there were two different distribution areas, by contrast, three different distribution areas were observed after 1988. It may be caused by the transition from warm and dry period to warm and wet period on the Qinghai-Tibetan Plateau in the mid and late 1980''s. Third, we separate the Qinghai-Tibetan Plateau into two different regions based on different air masses in summer. The dividing line was near 34°N-35°N inherited from the research by Tian Lide. In the north, there was a significant increase in mean annual snow cover days from 1979 to 2007 at the rate of 1.40 d/a (R²=0.39,P < 0.01), which was different from the tendency of the whole country. It was mainly caused by the increase in northwest during winter season. In the south, there was a significant decrease in mean annual snow depth from 1979 to 2007 at the rate of -0.04cm/a (R²=0.24,P < 0.01), which was consistent with the tendency of the whole country. It was mainly caused by decrease in southeast during spring and summer and autumn seasons.