Spatiotemporal evolution patterns of successive flood-heat extreme events in China from 1961 to 2014

Abstract

[Objective] Global warming has intensified the frequency of extreme events such as floods and heat waves, leading to an increased risk of successive flood-heat extreme(SFHE) events. Studying the spatiotemporal evolution of SFHE events has important scientific significance for the prevention and response to composite disaster risks. [Methods] Based on observation and reanalysis data, multiple statistical analysis method were used to analyze the spatiotemporal evolution of SFHE characteristics(frequency, duration, interval between floods and heat waves IFH, coverage area) in nine major river basins in China over the past 54 years(1961—2014), and explore the relative impact of floods and heatwaves on SFHE occurrence. [Results] The result indicate that:(1)The frequency, duration, and land coverage area of SFHE show a significant increasing trend, while IFH has a significant decreasing trend in China.(2)Spatially, the risk of SFHE is higher in the middle of the Southwest River basin, the south of the Yangtze River basin and the north of the Pearl River basin(>34 times/decade), while the duration is longer in the lower reaches of the Yangtze River basin, the Southeast River basin and the south of the Huaihe River basin(>13 d).(3)The periodicity of SFHE frequency varies in different watersheds, but there is a main cycle of 2.8a in China, which is most significant from the 1990 s to the early 2000 s.(4)The frequency of SFHE occurrence in the nine river basins is dominated by flood frequency, with the greatest impact in the Huaihe River basin. [Conclusion] The research result demonstrate that the risk of SFHE occurrence is significantly increasing, and the suddenness of SFHE is increasing in China. Overall, floods play a dominant role in the occurrence of SFHE.

Keywords

successive flood-heat extreme events / flood / heatwave / evolutionary characteristics / China / Yangtze River Basin / climate change / spatiotemporal changes