月、季尺度降雨变化特征及未来变化情况分析

A Study on Monthly and Seasonal Variation Characteristics of Rainfall and Its Future Changes

为科学探讨降雨变化特征,基于广西桂林市64 a降雨数据,采用相对变率、集中度和集中期分析月尺度降雨的稳定性和年内分布特征,采用线性趋势、Mann-kendall、和Morlet小波等分析4季降雨的趋势、突变及周期特征,采用相关函数法对未来降雨变化情况进行预估。结果表明:各月降雨相对变率较大,最大值达71.34%,月降雨序列不稳定,降雨集中度处于0.17~0.63之间,6月份为降雨主要集中期;春秋两季降雨呈现下降趋势,而夏冬两季则呈现上升趋势,4季降雨均于20世纪80-90年代发生突变,其中冬季降雨序列突变时间较早为1980年前后,秋季则较晚为1990年前后,4季降雨均呈现多尺度相互嵌套的周期特征,其中夏冬两季主周期较春秋两季短;预估未来降雨特征与现状相似,即降雨特征具有持续性。

For scientificly study the rainfall variation characteristics,stability and annual distribution characteristics of monthly scale rainfall were studied by analyzing the relative variability,PCD and PCP of the rainfall data,and then Linear trend analysis,Mann-Kendall,and Morlet Wavelet were applied to analyze the trend,mutation and period characteristics for the seasonal precipitation,finally the future characteristics was estimated by using the Correlation Function Method.The results show that the relative variability of rainfall is large,and the maximum value is 71.34%,monthly rainfall is unstable,PCD is between 0.17-0.63,and the rainfall concentrates in June;rainfall decreases during spring and autumn,while in summer and winter it shows a rising trend,the mutation for the seasonal rainfall takes place in the 80-90＇s of 20 th century,among them,the mutation time of winter precipitation sequence is relatively early,just around 1980,while the mutation time of winter precipitation sequence is relatively late,which is around 1990;season rainfall shows periodic characteristics of multi-scale nested,of which the main periods in summer and winter are shorter than those in spring and fall.It is estimated that the characteristics of future rainfall are similar to the present situation,that is to say,the characteristics of rainfall have durative characteristics.