Abstract:
In order to study the patterns and changing trends of different duration precipitation events, by using the time-frequency multi-resolution of wavelet analysis functions, the time-frequency multi-resolution function of the wavelet analysis was applied to this study. And the hourly rainfall observation data obtained from the Nanning National Ground Meteorological Station from 1971 to 2012 were divided into four durations: 1~3 hours, 4~6 hours, 7~10 hours and more than 10 hours from a precipitation duration point of view, which was used for analyzing the multi-scale cycle changes. The analysis results show that: ① the major periods of 1~3 hours, 4~6 hours, 7~10 hours and more than 10 hours time scales of the precipitation are respectively in 28, 27, 29, 11 years or so; ② the major periods of the four precipitation durations are 28, 26, 29, 12 years or so, except for the 7~10 hours, others have a very significant change in the precipitation durations, the positive and negative phases of the change are very remarkable; ③from the analysis results it can be predicted that in the next 2 years, the precipitation frequencies and precipitation of other durations will have a negative phase trend in addition to the 4~6 hours precipitation. The periodic variation law of the precipitation patterns of different durations can provide a basis for further exploring and analyzing the regional water cycle variation.