雄安新区地下水水位与降水及北太平洋指数的小波分析

Wavelet analysis between groundwater level regimes and precipitation,North Pacific Index in the Xiongan New Area

基于1991—2016年雄安新区4个地下水监测孔的长时间序列水位数据、降水数据及北太平洋指数(North Pacific Index,NPI),采用连续小波、交叉小波变换等方法,分析了三者的周期性变化及其之间的相互关系。结果表明:(1)雄安新区地下水水位、降水与NPI的主波动周期及各序列间共振周期均为1 a。(2)丰水年的地下水水位时滞小于全时段的地下水水位时滞,高降水量对潜水-承压水水位时滞的影响大于对承压水的影响。(3)地下水水位对NPI的时滞大于对降水的时滞;在丰水年,地下水水位对NPI的响应更快;地下水对降水和NPI的响应速度,明确反映了研究区地下水水位动态变化的主要气候影响因素是降水。

Based on the time series data of four monitoring wells of groundwater level regime and precipitation in the Xiongan New Area, together with the North Pacific Index （NPI） from 1991 to 2016, periodicities of the time series and their relationships are analyzed in this paper by adopting methods of continuous wavelet transform and cross wavelet transform. The results show that （ 1 ） the main periods of the groundwater level regimes, precipitation, NPI and their resonance periods between each other are all la. （2） The lags of the rich precipitation period are all shorter than the lags of the whole time. Rich precipitation has greater influence on the lags of groundwater level regimes in unconfined-confined aquifers than those in confined aquifers. （3） The lags of groundwater level regimes to NPI are all longer than the lags of groundwater level regimes to precipitation. Responses of groundwater level regimes to NPI are faster in rich precipitation years, especially for groundwater level regimes in the unconfined-confined aquifers. The results reveal the time lag relationship of groundwater level regimes with respect to precipitation and NPI.