Characteristics of extreme precipitation in Beijing-Tianjin-Hebei region from 1981 to 2016

Using daily precipitation data at 174 national weather stations in Beijing, Tianjin, and Hebei Province from 1981 to 2016, the spatial and temporal distributions and variations of extreme precipitation were analyzed using the percentile method and the linear tendency estimation method. The results showed that:(1) the precipitation thresholds of different percentiles showed a consistent spatial distribution. Distributions of annual extreme precipitation amount and extreme precipitation intensity were almost consistent with that of precipitation thresholds, although that for annual extreme precipitation days was opposite. (2) The annual extreme precipitation amount at each site was between 103.6~259.1 mm. The annual extreme precipitation days were about 3.0~4.0 days. The extreme precipitation intensity was between the amounts of the heavy rain and the rainstorm. The contribution of extreme precipitation to the total precipitation was above 28%. (3) The extreme precipitation sites and days showed consistent variation. Extreme precipitation was very active in July, August and October. (4) During the past thirty-six years, the variation distribution of annual extreme precipitation amounts was similar to those for the annual extreme precipitation days, intensity and contribution with more sites having exhibited declining trend. The increase and decrease of extreme precipitation amounts were large. Variation of extreme precipitation days was less than one day in ten years, and the decreasing trend of extreme precipitation intensity and contribution were significant.