Analysis of extreme rainfall trends based on MEV method with 29 long data series

Abstract

Since the mid-19th century global temperatures have increased significantly, so does the intensity of extreme rainfall. Previous studies have suggested that by the end of the century extreme rainfall intensity would increase by 10.5% and 28.2% for the low and high emission scenarios, and the centennial extreme rainfall would increase by 13.5% and 38.3%. For this model-based result, our aim is to verify it with observed historical data and find out the growth rate of extreme rainfalls. In this study, the MEV method was used to analyze the changes in the intensity of daily extreme rainfall in the 1-year, 10-year, and 100-year return periods at 29 stations and linearly fit them to determine the trends, and finally found that: the extreme rainfall showed an increasing trend in 70% of the stations in all data years, and the average growth rates in the 1-year, 10-year, and 100-year return period are 9.73%, 8.06% and 12.00%, re- spectively. From 1950 to the present, 56% of the stations have an increasing trend of extreme rainfall and the growth rate is 6% and 4% for 1-year and 10-year events, 2.4% for the 100-year events. For the growth rate per decade, the 1-year and 10-year events grow faster after 1950 than data from 1850, and the growth rate of the 100-year events becomes smaller.