基于小波变换的螺河径流、降水和蒸发时频变化及相关性分析

Time-frequency Variation and Correlation Analysis of Runoff,Precipitation and Evaporation in Luohe River Based on Wavelet Transform

运用小波变换对螺河1968—2022年的年径流、年降水和年蒸发进行多时间尺度特征分析,并利用交叉小波变换,从多时间尺度上探讨了年径流与年降水、年蒸发在不同时频中的相关性。结果表明:年径流主周期为16a,次周期为4a、8a、12a和24a;年降水主周期为12a,次周期为4a、8a、16a和28a;年蒸发主周期为22a,次周期为10a和15a。预测2023年螺河径流和降水还处于偏枯(偏少)期,蒸发还处于偏大期,且在16a时间尺度下,2025年前后径流和降水将由偏枯(少)转为偏丰(多),在15a时间尺度下,2025年前后将为蒸发偏大向蒸发偏小转变时期。年降水与年径流表现出相当好的正相关性;年蒸发与年径流总体表现为负相关性,蒸发也是影响径流变化的因素之一,但其对径流的影响程度不及降水。

Wavelet transform is used to analyze the multi-time scale characteristics of annual runoff,annual precipitation and annual evaporation of Luohe River from 1968 to 2022,and cross-wavelet transform is used to discuss the correlation of annual runoff,annual precipitation and annual evaporation in different time scales.The results show that the primary period of annual runoff is 16a,and the secondary periods are 4a,8a,12a and 24a;The primary period of annual precipitation is 12a,and the secondary periods are 4a,8a,16a and 28a;The primary annual evaporation period is 22a,and the secondary evaporation period is 10a and 15a.It is predicted that the runoff and precipitation of Luohe River will still be in a dry(less)period in 2023,and the evaporation will still be in a large period.In the 16a time scale,the runoff and precipitation will change from dry(less)to rich(more)before and after 2025,and in the 15a time scale,the evaporation will change from large to small.The annual precipitation and annual runoff show quite good positive correlation;The annual evaporation is negatively correlated with the annual runoff as a whole,and evaporation is also one of the factors that affect the runoff,but its impact is less than that of precipitation on the runoff.