Wavelet analysis of rainfall variation in the Hebei Plain

Based on the monthly and annual rainfall data of 1955–2000, the multi-time scales characteristics of seasonal and annual rainfall in the past 45 years in the Hebei Plain have been analyzed using Mexican Hat wavelet analysis in this article. The periodic oscillation of rainfall variation and the points of abrupt change at different time scales along the time series are discovered. According to the main periods, the trend of rainfall variation in the future has also been estimated. The results indicate that there are obvious periodic oscillations of 8–12 years and 4– 6 years for the seasonal and annual rainfalls variation. The variation trend of the summer rainfall is in agreement with that of the annual rainfall and both of them have the main periods of 1 year and 12 years. It is estimated, based on the main period of 1 year, that the amount of rainfall will be relatively small around 2003 and abundant around 2004-2007 in the Hebei Plain.