辽宁省近44年夏季降水变化及区域特征分析

利用辽宁省39个气象观测站1961-2004年夏季(6~8月)的降水资料,通过趋势系数、REOF、滑动均方差等方法,对辽宁省近44年夏季降水的时空变化特征进行了分析。结果表明,辽宁夏季降水长期变化呈微弱的减少趋势,以14 mm/10 a的速率减少。20世纪60年代到70年代中期降水以偏多为主,70年代中期到80年代初降水偏少,80年代中期降水偏多,80年代末到90年代初降水偏少,90年代中期降水偏多,90年代后期至今降水一直持续偏少。辽宁夏季降水分为中北部地区及盘锦、抚顺、营口地区、辽河以西部地区、东南部地区3个不同的区域,3个区夏季降水的长期变化趋势都为减少趋势,其中东南部地区降水减少趋势明显大于其他两个区。

Trends of summer precipitation and its regional characteristics in Liaoning Province,China during 1961-2004

This paper presents a study on the temporal and spatial trends of the summer precipitation(Jun-Aug),using trend coefficient,Rotated Empirical Orthogonal Function(REOF),and running standard deviation,based on monthly precipitation from 39 representative weather stations in Liaoning Province,China,during 1961-2004.The results indicate that the long-term overall trend of the summer precipitation in Liaoning decreased at a rate of 14mm per 10 years.Furthermore,the trends were varied with time.Positive trends were detected from 1960s to mid 1970s,in mid 1980s and mid 1990s.Negative trends were observed form mid 1970s to early 1980s,from 1980s to early 1990s,as well as from late 1990s to present.Based on the rotated EOF,this study identified three homogenous regions of summer precipitation:(1) central Liaoning,Panjin,Fushun and Yingkou;(2) west of Liao River;and(3) southeastern Liaoning.The summer precipitation in the southeastern Liaoning region decreased with a faster rate of 34mm per 10 years.