环青海湖地区近50年降水变化特征

Characteristics of Precipitation Changes around the Qinghai Lake Area in the Past 50 Years

本文利用刚察、天峻、茶卡、共和1961～2010年和海晏1976～2010年逐月降水量和≥0. 1、1. 0、5. 0、10. 0mm降水日数资料,分析了环青海湖地区降水变化趋势和异常年份。结果表明:近50年来该地区年降水量略有增加,东北部降水量大于西南部。降水量的增加主要集中在冬、夏季,年降水量在20世纪60年代中期和80年代末出现异常偏多,夏季降水量异常对全年降水异常的贡献最大。除≥1. 0mm的降水日数有所下降外,其他不同等级降水日数均呈增加趋势,增加幅度较小,平均每10a增加0. 3～0. 5d。

The change trend and abnormal years of precipitation around the Qinghai Lake area are ana- lyzed by using the monthly precipitation datas of Gangcha,Tianjun,Chaka,Gonghe from 1961to 2010 and Haiyan from 1976 to 2010and datas of the number of raining days of more than 0.1,1.0,5.0and 10.0ram.The results show that the annual precipitation in this area increased slightly in the past 50years,and the precipitation in the northeast is more than that in the southwest.The increase of precipitation is mainly concentrated in winter and summer.The annual precipitation is abnormally more in the mid-1960s and the late 1980s,and the summer precipitation anomaly contributes the most to the annual precipitation anomaly.Except for the decrease of the number of raining days of more than 1.0mm,the number of raining days of other grades shows an increasing trend with an average increase of 0.3-0.5d per 10a,and the increasing amplitude is small.