PROGRESS IN GEOGRAPHY ›› 2012, Vol. ›› Issue (1): 32-39.

### Wavelet Analysis of Rainfall Variations in Maigang Reservoir Catchment, Guizhou Province

LI Chunmei, LI Shuangcheng, WANG Hongya

1. Key Laboratory for Earth Surface Process, Ministry of Education, Department of Resources, Environments and Geography, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
• Received:2011-04-01 Revised:2011-06-01 Online:2012-01-25 Published:2012-01-25

Abstract: Maigang Reservoir catchment is located in Ziyun County of Guizhou Province, Southwest China. It has sub-tropical monsoon humid climate and is a carbonate-rock-dominated catchment of 7.5 km2. The environment here is very fragile, accompanied with serious problems, such as soil erosion, and rockification. Precipitation influences the environment to a great extent. So it is important to analyze the precipitation changes. Wavelet analysis is evolved from Fourier analysis, and it is usually used in multiple-scale analysis of the earth surface process, such as precipitation, runoff and temperature time series. It is an alternative and effective approach to analyze climate change at multi-time scales and forecast short-time climate variations. Based on the principle of wavelet analysis, the Mexican hat wavelet was chosen as the mother wavelet for continuous wavelet analysis in this paper: the multi-time scales characteristics of seasonal and annual precipitation in the past 48 years (1960-2007) of Maigang reservoir catchment were analyzed based on the monthly and annual precipitation from 1960 to 2007 by using Mexican Hat wavelet analysis. The periodic oscillation of precipitation variations and the points of abrupt changes of different time scales in the precipitation series of different seasons and years were discovered. The conclusions can be shown as follows. (1) The periodic oscillations of the spring precipitation were 8 years and 2 years. (2) There were periodic oscillations of 8 years and 1 year for both summer and annual precipitation. (3) The periodic oscillations of the autumn precipitation were 16 years and 1 year. (4) There were periodic oscillations of 3 years and 8 years for the winter precipitation. (5) Both the summer and annual precipitation had the periodic oscillations of 1 year and 8 years, and had the same trends of precipitation changes. The summer precipitation obviously influenced the annual precipitation.