基于PW-MK及小波分析的辽阳降水特征研究

降水作为水资源的重要补给,其特征分析对水资源保护、防汛抗旱等具有重要意义。基于辽阳地区16处雨量站长系列降水资料,采用模比系数差积曲线、预置白Mann-Kendall检验、小波分析进行了降水时空分布、趋势检验、突变分析及周期规律识别。结果表明,最大年降水量是最小年降水量的2.3倍,7、8月降水量占全年50%,东部山区降水多西部平原降水少;黄腊坨站、辽阳站、汤河水库站PW-MK检验统计量U分别为-0.85、-1.19、-1.43,且在1960年附近有突变点;小波分析结果显示在3~4、10~11、25~35 a的3组时间尺度有明显的循环变化。在1951—2014年中,辽阳地区降水年内分配集中、变化较大,总体呈现"丰-枯-丰-枯"变化,有不同时间尺度连枯、连丰年份出现;降水总体呈现减少趋势,汤河水库站显著减少,1960年左右出现降水突变点;具有明显的约25~35 a、10~11 a主周期循环,3~4 a小尺度周期嵌套于主周期,3组不同时间尺度的周期振荡共同作用辽阳降水。

Study of the Precipitation in Liaoyang Province Using PW-MK and Wavelet Analysis

Precipitation is a main contribution to water resources and its analysis plays an important role in protecting water resources,alleviating flood and draught.In this paper,we analyzed the spatiotemporal variation of precipitation in Liao Province using the precipitation data measured from 16 weather stations across the province.The analysis was based on residual mass curve of modulus coefficient,pre-whitening Mann-Kendall and the wavelets methods.The results showed that the maximum annual precipitation is 1.3 times more than the minimum,and the precipitation from July to August accounted for 50％ of annual precipitation.There was more precipitation in the eastem mountainous areas than in the westem plain in the province.The statistics U calculated from the PW-MK for Huanglatuo Station,Liaoyang Station and Tanghe Reservoir Station was-0.85,-1.19,-1.43,with anabrupt in the 1960s.The wavelet analysis showed noticeable periods of 3～4 a,10～11 a,25～35 a in the precipitation.In 1951-2014,the precipitation is not uniform within a year,and the annual precipitation varied widely followingthe cycle of wet-dry-wet-dry.In summary,the precipitation decreased during the studied period with an abrupt change in the 1960s.Annual precipitation repeated periodically after each 25～35 a,with 10～11 a period and 3～4 a period further nested in the main period.