Identifying regional patterns of extreme wet events in mainland China

Abstract

Study RegionThe study region of this research is mainland China. With an improved Otsu method, the study region is clustered into 7 regions based on the spatial characteristics of the precipitation data. Study FocusThis research focuses on the mechanisms and predictions of extreme wet events in mainland China. In this paper, the drivers, regional patterns, and near-future trends of extreme wet events in mainland China are analyzed and discussed. New Hydrological Insights for the RegionThe three major drivers of extreme wet events, identified using principal component analysis (PCA), are the Atlantic Multidecadal Oscillation (AMO), Northern Hemisphere Average Temperature (NH temp), and Pacific Decadal Oscillation (PDO). Increasing trends of extreme wet events are identified in the Northeast China, North China, Southeast China, and Western Northwest China regions. In the Eastern Northwest China region, extreme wet events are decreasing. In the Southwest China region and the Tibetan Plateau region, the frequencies of extreme wet events remain the same. The results show that changes of one standard deviation in the three drivers roughly lead to a 10% increase in extreme wet events in the Northeast, Southeast and Western Northwest regions and a 10% decrease in the Eastern Northwest region.