太行山山前平原降水量特征及其分布的小波分析——以栾城为例

WAVELET ANALYSIS OF PRECIPITATION AND ITS DISTRIBUTION IN THE PIEDMONT REGION OF TAIHANG MOUNTAINS—A CASE STUDY AT LUANCHENG STATION

运用墨西哥帽函数(MexicanHatFunction)小波分析方法对太行山山前平原典型地区的栾城站40年来的降水量以及当地典型作物冬小麦不同生育期阶段的降水量进行了小波分析。结果表明,分时段的降水量并无一个稳定的周期,而是变周期。该区全年降水量变化在40年尺度上可分为1980年前的偏多期和其后的偏少期;10～30年尺度上可分为60年代末以前的偏多、1997年以后的偏少和这期间的动荡期;在较小时间尺度上存在5～7年的周期变化,今后10年内年降水量的总体趋势依旧偏少,5年内为少中有稍偏高于平均降水量的趋势。冬小麦全生育期均存在较明显的4个阶段的交替变化,1967年以前的偏多期、1967～1983年左右的偏少期、1984～1994年左右的偏多期、1995年以后的偏少期。

A 40-year time series of annual precipitation and its distribution during the growth period of winter wheat at Luancheng Station, Agro-ecosystem Experimental Station of Chinese Ecological Research Network, CAS, located in typical region of Piedmont region of Taihang Mountains, is analyzed by statistic and Mexican Hat Function wavelet analysis. The results shows that the period in different intervals is not stable, but variable. The annual precipitation variation can be divided into two periods, more than mean precipitation before 1980 and less than mean later, on the 40 years scale. On 10 to 30 years scale, it is richer before 1960s and less after 1997, and more or less between them. Furthermore, periodic variation of 5-7 years is found in shorter time scale. In a whole, from now to 2010, annual precipitation will have still a decreasing tendency, but it will be more than that of mean during the coming five years, possibly. Four times of alternate variation, more than mean precipitation before 1967, less from 1967 to 1983, richer from 1984 to 1994 and less after 1995, are found in the whole growing season of winter wheat.