PREDICTION OF THE RETURN PERIOD OF DROUGHT IN PANJIAKOU HYDROLOGICAL STATION BY PEASON-III PROBABILITY DISTRIBUTION

摘要

Peason-III probability distribution is chosen to simulate monthly average runoff of Panjiakou hydrological station, and calculate the minimum value of monthly average runoff at different return periods throughout March, April, May, and the whole spring. The results show that minimum value of monthly average runoff was 85.59, 62.04, 50.24, 40.74, 30.33, 23.55, and 17.46 m3/s when return periods were fixed at 2, 10, 20, 50, 100, and 200 years, respectively. In addition, the fitting results were credible by comparing the observed return periods. The return periods of monthly average runoff of Panjiakou hydrological station in March, April, May, and the whole spring of 2001 were 147.00, 254.07, 1.80, and 34.07 years, respectively.