Analysis of precipitation variation characteristics in Pi-Shi-Hang Irrigation District from 1960 to 2021

In order to reveal the characteristics of precipitation variation in Pi-Shi-Hang Irrigation District from 1960 to 2021, the characteristics of precipitation variation in the irrigation area were analyzed by linear regression simulation, Mann-Kendall trend test and Morlet wavelet analysis. The annual, flood season and non-flood season precipitation in Pi-Shi-Hang Irrigation District showed an increasing trend, and the change tendency rates were 11.6 mm/(10 a), 12.5 mm/(10 a) and 2.09 mm/(10 a), respectively, the increasing trend during the flood season is relatively significant. The precipitation has an abrupt change from 2020 to 2021, but the change trend is not significant. The annual precipitation has the oscillation period of 9 a, 26 a, 44 a and 3 a. The precipitation in flood season has 9 a, 26 a, 17 a and 44 a oscillation period, and the precipitation in non-flood season has 46 a, 20 a, 6 a and 9 a oscillation period, and the real part isolines of wavelet coefficients are all positive phase and not closed. The results show that the precipitation in Pi-Shi-Hang Irrigation District is still increasing in the future.