近50a中国西北地区东部降水特征  

Precipitation in the Eastern Part of Northwest China in Recent 50 Years

作　　者：王晖[1] 隆霄[1] 马旭林[2] 刘燕飞[1] 

机构地区：[1]兰州大学大气科学学院,甘肃兰州730000 [2]南京信息工程大学大气科学学院,江苏南京210044

出　　处：《干旱区研究》2013年第4期712-718,共7页Arid Zone Research

基　　金：气象行业专项(GYHY201006023);兰州大学中央高校基本科研业务费专项资金项目(LZUJBKY-2010-13;LZUJBKY-2012-K04)

摘　　要：利用我国西北地区东部54个气象站1960—2009年的降水资料,采用M-K检验和小波分析方法,对该地区的降水特征进行了分析。结果表明:①西北地区东部降水量呈微弱下降趋势,1990年后降水减少趋势更为明显,Ⅱ区降水变化趋势较Ⅰ区更加显著;②该地区降水频次以弱降水和中等强度降水为主,占降水总天数的70%以上,弱降水频次减少趋势显著;③中等强度降水和强降水的降水量占全年降水的75%以上,中等降水的降水量呈减少趋势,是造成年降水量减少的主要原因;④小波分析结果显示,年降水、中等降水和强降水序列均存在显著的3 a和5 a短周期,其中Ⅰ区和Ⅱ区的中等降水和强降水小波周期在20世纪70年代之后完全不同,中等降水的减少与70年代周期的变长密切相关。Based on the precipitation data observed by 54 meteorological stations in the eastern part of northwest China during the period of 1960-2009,the variation of precipitation in this region was analyzed using the Mann-Kendall test and wavelet analysis.The main results were as follows：（1） Precipitation in the study area was in a slight decrease trend,the precipitation reduction was more obvious after 1990,and the variation of precipitation in area Ⅱwas more significant than that in area I;（2） The precipitation frequency in the study area was dominated by weak and moderate precipitation events,which accounted about 70% of the total precipitation days,and the decrease of weak precipitation frequency was obvious;（3） The proportion of moderate and heavy precipitation accounted for more than 75% of annual precipitation.Decrease of annual precipitation was mainly caused by the decrease of moderate precipitation;（4） The results of wavelet analysis revealed that there were the 3-year and 5-year fluctuation periodicities of annual,moderate and heavy precipitation,the periodicities of moderate and heavy precipitation in area I were completely different from those in area Ⅱafter the 1970s,and the decrease of moderate precipitation was closely related to the variation of moderate precipitation in the 1970s.

关 键 词：降水频率 降水强度 MANN-KENDALL 小波分析 西北地区东部 

分 类 号：P468.024[天文地球—大气科学及气象学]