1961—2014年中国洪水-热浪复合极端事件特征的时空演变规律

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

摘要

【目的】全球气候变暖加剧了洪水和热浪等极端事件发生的频率，导致洪水热浪复合极端事件(Successive flood-heat extreme,SFHE)风险上升，研究SFHE事件的时空演变规律，对复合灾害风险防控及应对具有重要的科学意义。【方法】基于观测和再分析数据，采用多种统计分析方法，分析了过去54 a(1961—2014)中国九大流域SFHE特征(频次、历时、洪水和热浪的间隔IFH、覆盖面积)的时空演变规律，探讨了不同地区洪水和热浪对SFHE发生的影响。【结果】结果表明：(1)中国SFHE频次、历时和土地覆盖面积整体呈显著增加趋势，而IFH呈显著减少趋势；(2)空间上，西南诸河中部、长江流域南部和珠江流域北部SFHE发生的频次较高(>34次/10 a),而历时在长江下游、东南诸河和淮河流域南部较长(>13 d);(3)不同流域SFHE频次的周期性差异较大，但整体存在2.8 a的主周期，该周期在1990 s至2000 s前期最为显著；(4)九大流域SFHE发生的频次由洪水频次主导，其影响在淮河流域最大。【结论】研究结果表明中国地区发生SFHE的风险呈显著上升趋势，其突发性增强，总的来看洪水对SFHE的发生起主导作用。

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.

关键词

洪水热浪复合事件 / 洪水 / 热浪 / 演变特征 / 中国 / 长江流域 / 气候变化 / 时空变化

Key words

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

基金资助

国家自然科学基金项目(52279016)

广东省自然科学基金项目(2023A1515011760)