环青海湖地区气候变化及其环境效应

Climate Change and Its Environmental Effects in the Surrounding Area of Qinghai Lake

通过对环青海湖地区近44年平均气温、降水、蒸发量、风速及大风日数等气候要素的定量化统计分析,以及环青海湖地区草地、青海湖变迁、沙漠化等具指示性意义的生态要素指标进行研究,揭示了气候变化对该区域生态与环境的影响效应。结果表明:①近44年中,年、季的平均气温均表现出显著增温趋势,年平均气温增幅为0.262℃/10年;年降水量在20世纪60年代和70年代分别偏少3.8%和5.2%,80年代以1.37mm/10年趋势增加,90年代与21世纪初接近平均值;春、夏和冬季及年蒸发量呈减小趋势,年蒸发量以66.53mm/10年倾向率减小;月平均风速以0.01(m/s)/10年倾向率减小,大风日数以4.5d/10年倾向率减少;②该区域牧草生物量与降水量呈正相关,由于气温显著升高,且季节性降水变率大,不仅影响牧草的生育期,且造成牧草地上生物量的波动;③青海湖水域面积的自然摆动与年平均气温以及秋、冬季气温呈显著负相关,而与地表蒸发量却呈正相关,在20世纪60年代和70年代升温不显著时,水域面积与春季降水呈正相关,90年代显著升温以后,气温对青海湖水域面积的影响占主导作用;④环青海湖地区暖干化气候趋势是沙漠化发展迅速的主导因素。

Through quantitative analysis of annual mean temperature, annual precipitation, annual evaporation amount, wind speed, windy days, grassland change, lake transition and land desertification trend in recent 44 years in the surrounding area of Qinghai Lake, this paper reveals the effects of regional ecological environment resulted from climate change. 1 ） During the last 44 years, annual and seasonal mean temperatures （at the speed of 0. 262℃/10a） represent a trend of evident increase. Annual precipitation decreased 3.8% in the 1960s and 5.2% in the 1970s, but increased by 1.37mm/10a in the 1980s, reaching the average value in the 1990s and beginni amounts in spring, summer and winter reduced with a rate ng of 21st century. Annual evaporation of 66.53mm/10a. Average wind speed decreased with a rate of 0.01 （m/s）/10a, while windy days decreased with a rate of 4.5 d/10a; 2） The regional forage biomass and precipitation is positively correlated. Significant increase of temperature and strong variation of seasonal precipitation affected the forage＇ s growth period, and posed a fluctuation of pasture biomass; 3） Coverage area of water in Qinghai Lake is significantly negatively correlated with annual mean temperature and seasonal temperatures in autumn and winter, while positively correlated with water surface evaporation of the lake. During the 1960s and the 1970s, a positive correlation existed between climate, Qinghai water coverage area of the lake and spring precipitation. Since the 1990s, with the warming of the temperature has been playing a dominant role on the impact of the water coverage area of Lake; 4） Warming and drying climate in the surrounding area of Qinghai Lake is the dominant factor that resulted in rapid development of desertification.