承德市近58年降水序列多时间尺度分析

目的]分析承德市近58年降水序列的变化规律。方法]利用墨西哥帽小波,对承德市1951～2008年逐月降水数据进行多尺度分析,揭示了承德市降水变化多时间尺度的复杂结构,分析了不同时间尺度下降水序列的变化周期和突变点,并确定了各序列中存在的主周期。结果]降水在年代际尺度(10年以上)上存在高低值中心;年际尺度(10年以下)上振荡复杂多变,但4年尺度有明显的高频振荡。4年降水周期在小波方差分析中得到了验证,M-K检验也印证了小波分析的结论。结论]从干湿交替的情况可以判断,多雨年份明显减少,且当前降水仍然偏少。

Multi-time-scale Analysis of the Precipitation Series in Chengde in Recent 58 Years

Objective] The research aimed to analyze variation rule of the precipitation series in Chengde City in recent 58 years.Method] Mexican hat wavelet was used to analyze the multi-scale characteristics of the monthly precipitation data in Chengde from 1951 to 2008.We revealed multi-time-scale complex structure of the precipitation change in Chengde,analyzed the change cycles and mutation points of the precipitation series under different time scales,and identified primary periods in different series.Result] There were high/low value centers of the precipitation in interdecadal scale(more than 10 years).In interannual scale(below 10 years),oscillation was complex and variable,but 4-year scale had obvious high-frequency oscillation.Wavelet variance verified existence of the 4-year precipitation cycle,and M-K test also confirmed conclusions of the wavelet analysis.Conclusion] We could judge from alternating wet and dry conditions that the wet years decreased significantly,and the current precipitation was still less than normal.