Estimation of design precipitation in Beijing–Tianjin–Hebei region under a changing climate
Lei Yan, Dongyang Lu, Peng Hu, Pengtao Yan, Yongxin Xu, Jihong Qi, Fei Liu, Jing Li
Abstract
Under changing environments, conventional methods based on an assumption of stationarity can lead to unreliable estimates of design rainfall quantiles. In this study, the trend of six extreme precipitation indices in the Beijing–Tianjin–Hebei region was analysed using different methods. Nonstationary models were established for annual maximum one-day precipitation (RX1d) and annual total precipitation when daily precipitation is greater than 95% of daily precipitation in a year (R95p) exhibiting significant trend, while stationary models were established for the two indices showing no significant trend. Finally, the nonstationary and stationary design precipitation were estimated using the average design life level method and the stationary method, respectively. The results indicated that for some stations in the east and south, a significant decreasing trend was observed for RX1d and R95p. This resulted in the overestimation of their design precipitation using the stationary methods and altering the spatial distribution of precipitation extremes for future period near these stations.