中国夏季降水的时空分布特征分析

Temporal and Spatial Distributions of Summer Precipitation Analysis in China

为探讨中国东部夏季降水的时空分布特征,利用中国区域1980-2012年6月1日至8月31日1718站逐小时降水资料,运用Γ分布函数和百分位阈值法分析了中国东部降水的空间分布特征,运用小波分析等方法分析了中国东部降水的时间变化特征。结果表明,西北大部分地区为＂形状参数主导＂区,极端天气事件发生较少;东南大部分地区为＂尺度参数主导＂区,出现强降水的可能性较大;华北、四川和华南部分地区短时强降水发生的强度较大。中国夏季降水在20世纪80年代初期至80年代末期呈显著的下降趋势,在20世纪80年代末期至21世纪10年代末期上升趋势显著;从降水丰枯情况而言,1980-1992年为枯水期,1992-1998年为丰水期,1998-2011年为平水期;中国夏季降水存在明显的16年周期变化,并在20世纪90年代初期发生了显著的年代际突变。

To investigate the spatial and temporal distribution of summer precipitation in eastern China,the hourly rain gauge data of 1718 stations over China from June 1st to August 31 st during 1980 to 2012 were analyzed in this paper.The Γ distribution function and percentile threshold method used to analyze the spatial distribution of precipitation in eastern China. The wavelet analysis method was adopted to analyze the time-varying characteristics of precipitation in eastern China. The results indicate that most parts of the northwest China are shape-parameter dominated regions where the probability of extreme weather events is low,while the most parts of southeast China are scale-parameter dominated regions with large scale parameters where the probability of extreme weather events is high. The intensity of short-time torrential precipitation is strong the eastern area of North China,eastern Sichuan and South China. The summer precipitation appear a significant decreasing trend over China from early 1980 s to late 1980 s,while it a significant increasing trend from late 1980 s to late 2010 s,and a little declining trend during late 2010 s. As for the wet and dry conditions,it is the wet period from 1980 to 1992 while the dry period from 1992 to 1998; the period from 1998 to 2011 modestly fluctuating. It also indicates that the precipitation over China show an obvious oscillation with a 16 year cycle-period and a striking decadal significant catastrophe happened in the early 1990 s.