The Characteristics and Causes of Drought and Heat Wave Compound Events and Their Single Events in the Yangtze River Basin from 1961 to 2022
Online published: 2026-05-06
Global warming has increased the frequency and intensity of drought and heatwave events,exerting profound impacts on socioeconomic development. Based on meteorological observation data and reanalysis data in the warm season(May to September)from 1961 to 2022 in the Yangtze River Basin,this study compares and analyzes the climatic evolution characteristics of heatwaves,droughts,and drought and heat wave compound events(CDHEs). The possible causes and differences influencing the three types of events are preliminarily inves‐ tigated,with the main conclusions as follows. In terms of spatial distribution,the frequency and duration of heat‐ waves are the highest in the Three-River Headwaters region(upper reaches)and the Yangtze River Delta(lower reaches),exceeding 2 times·a⁻¹ and 13 d·a⁻¹,respectively. Droughts and compound drought-heatwave events occur more frequently and last longer in the Sichuan Basin and near the main stem of the Yangtze River. The dura‐ tion of droughts is about nine times that of heatwaves,while the frequency of droughts is only 0. 6~0. 8 times that of heatwaves. The frequency and duration of compound events are relatively low in the southern middle and lower reaches,whereas both heatwaves and droughts occur frequently over the western Sichuan Plateau. From 1961 to 2022,heatwave events,drought events,and CDHEs in the Yangtze River Basin have generally shown an increasing trend,except for the duration of drought events. The most rapid increase occurred in the upper reaches,with a significant and enhanced trend in extremity since the beginning of the 21st century. The correla‐ tion coefficients between the intensity of the Western Pacific Subtropical High(WPSH)and the South Asia High (SAH)and heatwave events reach up to 0. 472 and 0. 484,respectively. A westward-shifted,larger,and stron‐ ger WPSH,as well as a stronger and northward-shifted SAH center,correspond to longer durations of heatwaves and compound events,especially in the upper reaches,whereas the correlations with droughts are weak. Higher sea surface temperatures(SST)in the Tropical Indian Ocean correspond to longer durations of drought and heat‐ wave events in the Yangtze River Basin,with a more significant impact on heatwave events in the upper reaches, where the correlation coefficient exceeds 0. 5. Lower SST in the equatorial Pacific is associated with shorter dura‐ tions,except for droughts. In addition,drought heatwave compound events in the upper reaches were dominated by surface sensible heating before the 21st century,and by latent heat release afterward. In the middle and lower reaches,latent heat release from surface evaporation plays a leading role. The duration of heatwaves shows a stronger correlation with land surface processes.
CHEN Xiaoxiao, HUANG Zhiyong, HU Yiyang, QIN Pengcheng . The Characteristics and Causes of Drought and Heat Wave Compound Events and Their Single Events in the Yangtze River Basin from 1961 to 2022 [J]. Plateau Meteorology, 0 : 1 . DOI: 10.7522/j.issn.1000-0534.2025.00111
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