长江源沱沱河区45a来的气候变化特征

利用1959—2003年长江源区沱沱河气象站气温、降水、积雪等地面观测资料,对年代际的气候变化特征及其影响进行了分析.结果表明:该区域45 a来夏季增温比较明显.20世纪90年代四季平均气温、平均最高和平均最低气温比最冷的80(或60)年代偏高0.6~1.2℃;降水量(含积雪量)冬季呈增加的趋势,夏季呈减少的趋势,秋、春季降水量增加而积雪量减少;年大风日数80—90年代较60—70年代偏多.80年代是夏季温度升高、降水减少、大风日数增多的暖干气候背景,90年代以来继续加剧,并逐步扩展到春、秋季节,使得该区域的草场退化、冰川和冻土消融加快、湿地资源减少、生态环境恶化.

Climate Change in Tuotuohe Area at the Headwaters of Yangtze River

Using the data of temperature,precipitation,snow cover and so on from the Tuotuohe Meteorological Station at the headwaters of Yangtze River from 1959 to 2003,the annual and seasonal series of meteorological factors are worked out.The interannual and decadal climate changing features are analyzed preliminarily by using the climate diagnosis method.It is found that in the recent 40 years,summer air temperature increased obviously in the region.The annual maximum,minimum and seasonal mean air temperatures in the 1990s were 0.6～1.2℃ higher than that in the 1980s(or the 1960s).In the 1980s the air temperature was the lowest. Precipitation has an increasing trend in winter and a decreasing trend in summer.precipitation in spring and autumn increased but snow depth decreased.Strong wind days were more in the 1980s and the 1990s than that in the 1960s and the 1970s.In general,summer temperature increase,precipitation decrease,and strong wind days increase in the 1980s.This climate changes were strengthened in the 1990s,and expanded to spring and autumn,as a result,grassland deteriorating,permafrost thawing and glacier retreating quickly,wetland shrinking,and finally,eco-environment worsening.