Spatiotemporal analysis of consecutive extreme wet days in China from 1980 to 2020

Consecutive extreme wet days (CEWDs) typically affect the likelihood of flooding and landslides and have negative effects on both natural and artificial ecosystems; however, the spatiotemporal changes in their features are still unclear at the national scale. Investigating changes in the frequency and intensity of such events is essential for climate risk management. Here, this study thoroughly analysed CEWD features in China from 1980 to 2020 using the daily observation dataset. We also evaluated and compared the ability of two widely used precipitation products, the European Centre for Medium-Range Weather Forecasts Reanalysis 5th Generation (ERA5) and the Multi-Source Weighted-Ensemble Precipitation version 2 (MSWEP), to detect CEWD features. According to the observation data, the frequency and intensity of CEWD events are related to local climate and present high eastern and low western spatial patterns across China. Since 1980, more than half of China's mainland has experienced increases in both the frequency and intensity of CEWDs. Some stations detected decreasing trends in CEWD frequency and amounts, which are primarily located in the eastern coastal regions and southwest of warm temperate humid/subhumid regions. The ERA5 precipitation product generally outperforms MSWEP data in detecting CEWD events, and the latter significantly underestimates the annual frequency and amounts of CEWDs. These findings provide basic and valuable information regarding CEWD features across China and where such studies can be conducted based on precipitation datasets. Furthermore, these findings will also aid policymakers in managing extreme precipitation-related natural hazards.

Automated summary

This study analyzed the features of consecutive extreme wet days (CEWDs) in China from 1980 to 2020 using observation data. It found that the frequency and intensity of CEWDs are related to local climate and exhibit a high eastern and low western spatial pattern in China. Since 1980, more than half of China's mainland has experienced an increase in both the frequency and intensity of CEWDs, except for some eastern coastal regions and southwest warm temperate humid/subhumid regions where a decreasing trend was observed. The ERA5 precipitation product outperforms the MSWEP data in detecting CEWD events, which underestimates the annual frequency and amounts of CEWDs. These findings provide valuable information for understanding and studying CEWD features in China and will assist policymakers in managing extreme precipitation-related hazards.