环青海湖地区气候变化及其对荒漠化的影响

Climate Change and Its Impact on Desertization around Qinghai Lake

对环青海湖地区 1976年以来的气温、降水、蒸发等气候要素的气候变化趋势及突变现象进行了分析和检验。结果表明 :年平均气温及春、夏、秋、冬四季气温均呈上升趋势 ,其中以秋、冬两季最为明显 ;年平均降水量及春、夏、冬季降水自 90年代后出现减少趋势 ,秋季降水始终呈减少趋势 ,且线性变率达 - 7.2 8mm/ 10a;各季及年蒸发量呈增大趋势 ,其中年、夏季蒸发量的线性变率分别为11.7、9.39mm/a。各季及年气温出现过一次明显的增暖现象 ;降水虽然出现过一次明显的增加和减少 ,但增加出现在 80年代 ,而减少则出现在 90年代 ;同样 ,蒸发也出现过一次明显的增大和减小现象 ,只是减少出现在 80年代 ,而增大则出现在 90年代。这种气候趋势和突变现象的发生 ,加剧了环青海湖地区荒漠化的蔓延 ,致使草地退化、河流流量减少、湖泊水位下降 。

The climatic variation tendencies and jump phenomena of air temperature, precipitation, evaporation and etc around Qinghai Lake since 1976 are analyzed and verified. The result shows that the four seasons and the annual mean precipitation and air temperature are increasing. Among them, this tendency is more significant in autumn and winter. The annual mean precipitation and precipitation in spring, summer and winter have been decreased since 90s, especially, in the autumn, its linearity variation rate is -7.28 mm/10a; each season and annual evaporation appear to increase, its linearity variation rate of year and summer is 11.7 and 9.39 mm/a respectively. Each season and annual air temperature had a significant warming phenomenon. Although precipitation had a significant increasing and decreasing phenomena, but its increasing was in 1980s, and the decreasing was in 1990s; meanwhile, the evaporation also had a significant increasing and decreasing phenomena, its decreasing was in 1980s while its increasing was in 1990s. When the climatic tendency and jump are happening, it increase desertization expanding around Qinghai Lake, causes grassland degeneration, river flow decreasing and lake level descent; that is, it has a severe impact on ecological environment.