40a来江河源区的气候变化特征及其生态环境效应

Climate Change and Its Impact on the Eco-environment in the Source Regions of the Yangtze and Yellow Rivers in Recent 40 Years

通过江河源区分布的 5个气象台站有关气温与降水的多年数据 ,分析了近 40a来江河源区的气候变化特征 .结果表明 :近 40a来江河源区气候变化的总趋势是气温升高 ,降水量增加 ,但降水量的增加主要体现在春季降水和近 15a来冬季降水的明显增加上 ,对植被生长起重要作用的夏季降水量却呈明显减少趋势 ;江河源区 2 0世纪 80年代 10a平均气温比 5 0年代高 0 .12～ 0 .9℃ ,大部分地区高于0 .3℃ ,属于青藏高原高温区或升温幅度最大的地区之一 ,平均升温 0 .44℃ ,明显比全国平均升温 0 .2℃要高出一倍 .在这种背景下 ,与植被生长关系密切的 4、5月和 9月气温呈现持续下降态势 .江河源区脆弱的生态环境体系对气候的这种变化响应强烈 ,冰川退缩、多年冻土消融加剧 。

Based on precipitation and temperature data obtained from the five meteorological stations in the source regions of the Yangtze and Yellow Rivers, the features of climate change in the recent 40 a are studied. The results show that the trend of climate change in the regions, as a whole, is both temperature and precipitation rise. However, precipitation increase mostly results from precipitation rise in spring and winter. Precipitation in summer, which takes an important contribution to vegetation growing, declines in the recent 40 years. In the source regions, the decadal mean temperature in the 1980s was higher than that in the 1950s by 0.12～0.9 ℃, and by 0.3 ℃in most part of the study area. Contrasting to the mean temperature increasing in whole China, 0.2 ℃, the regions are the highest ones with temperature rising, 0.44 ℃ on the average.However, the temperature in April or May and September, which have very important significance to the growth and development of high cold meadow vegetation, decline. The eco environment in the Tibetan Plateau is very vulnerable, which is sensitive to the regional climate change. The climate in the plateau is becoming drier and warmer, resulting in a gradual degradation of permafrost. Both climate change and degradation of permafrost result in degradation of high-cold meadow vegetation.