Study on Precipitation Evolution Characteristics in Tongzhou District of Beijing in Recent 65 Years

Based on the 65a (1956–2020) precipitation series data of 11 rainfall stations and 5 surrounding rainfall stations in Tongzhou District, Beijing, the evolution characteristics of precipitation in Tongzhou District on spatial, interannual and intra annual scales are comprehensively analyzed using cumulative anomaly method, 5a moving average method and spectral analysis method, and the future change trend is predicted using ARIMA model. The results show that: 1) the annual average precipitation in Tongzhou District is higher in the middle and northwest and lower in the southwest, and the precipitation between June to August, accounts for more than 70% of the annual precipitation; 2) In general, the precipitation shows a fluctuating downward trend at the rate of -2.42 mm a-1, in which the precipitation in summer decreases at the rate of -2.68 mm a-1, while the precipitation in spring and autumn increases at the rates of 0.35 mm a-1 and 0.26 mm a-1 respectively; 3) The abrupt change of precipitation occurred in 1959 and 2000, which were 990.2mm and 239.4mm respectively; 4) There are 3∼8a and 14∼16a oscillation periods on the inter annual scale of precipitation, the prediction results of ARIMA model show that the precipitation will increase about 40 mm in the next five years.