Change characteristics of observed precipitation extremes in the Weihe River Basin of China

The flood disaster has a higher frequency and more influences under the impacts of global climate change and urbanization for the past several decades. The primary objective of this study is to provide more comprehensively the change characteristics in observed precipitation extremes for the period of 1969-2016 in the Weihe River Basin (WRB) of China. Fourteen extreme precipitation indices (EPIs) were defined to describe the precipitation extremes. Daily observed precipitation from 35 surface meteorological stations in the WRB was used to calculate EPIs. The RClimRex software was used to calculate 14 EPIs, and the trends were analyzed using the Mann-Kendall non-parametric method. The spatial distribution of the typical EPIs was also presented. The results showed that: 1) Generally, the spatial and temporal variations of precipitation extremes varied for different EPIs and different regions. More EPIs were mainly increasing trends dominated. Few stations exhibited statistically significant trends at significant levels of both 5% and 10%. 2) The spatial distributions of increasing and decreasing trends for the 14 EPIs were scattered. The stations which had statistically significant trends were mainly located at the northern and southeast regions, some of which were outside the WRB borders. 3) The reasons of the spatial and temporal variability need to be further investigated from the aspects of climate change and urbanization, which will be our further works.