近20年新疆中部明显增湿事实的进一步分析

Further Analyses of Obvious Moistening in Central Xinjiang in Recent 20 Years

利用1951-2008年新疆中部15站的实测降水及博斯腾湖部分实测水文资料,用小波分析等统计方法,进一步分析了近20年新疆中部明显增湿的事实。结果表明:(1)新疆中部过去60年交替出现了3段约20年的干、湿期,近20年明显增湿期的平均雨量比气候值增加了约10%～20%。(2)近20年新疆中部的明显增湿主要出现在夏季。(3)过去60年新疆中部降水变化的准3年短周期相当清楚。另外,还存在约20年的中周期变化。(4)鉴于新疆中部的明显增湿还不是全西北区尺度,也考虑到新疆中部降水准20年的固有周期,且近20年的湿期似已结束,故近20年的增湿可能仅是新疆降水准20年周期变化的响应。

The obvious moistening fact in Central Xinjiang（CX） in recent 20 years was further analyzed utilizing the observed precipitation data at 15 stations in CX in 1951-2008 and partly hydro-meteorological data and the wavelet technique.The main conclusions are as follows：（1） Both the meteorological and hydrological data show that there exist three dry/wet episodes： i.e.,gait wet one in 1946-1960,evident dry one in 1961-1986,and striking wet one in 1987-2007,in CX in the past 60 years.Each lasted 20 years or so,the rainfall in the last 20 years increase by 10%～20% than usual.（2） The moistening in recent 20 year is mainly occurring in summer.（3） The short period（quasi-three years） change for the precipitation in CX in past 60 years is quite clear;and the midrange-period change about 20 years is also clear especially in summer.（4） Judging from above moistening area is not on the whole Northwest China scale,the area precipitation had already decreased in the past three years,and also the precipitation climate projection in drought area has much more uncertain.It is possibly that above moistening is just the reflection about 20 year interdecaded change of Xinjiang precipitation.