Multiple time scale analysis of ET_0 series based on Morlet wavelet
Meizhao Lv · Engineering Journal of Wuhan University · 2009
With the monthly reference crop evapotranspiration from 1984 to 2003 of Liuyuankou Irrigation District as the basic information,the reference crop evapotranspiration time series is denoised by Dmey wavelet and dealt with anomalies at first.And then the multiple time scales of it are analyzed using Morlet complex wavelet.The evolution characteristics of it in various time scales are displayed.The result shows that the main periods of the reference crop evapotranspiration are around 120 months,55 months,40 months and 16 months respectively.The four kinds of period variations lead the reference crop evapotranspiration fluctuation in the whole time domain.And the major variant trend of the reference crop evapotranspiration is increasing gradually from the lower level since the later 2003.It will be sustained for several months.