Pan Xiaolong, Wang Weiguang, Shao Quanxi, Wei Jia, Li Hongbin, Zhang Fengyan, Cao Mingzhu, Yang Liyan
The National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing 210098, China; College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China.
The National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing 210098, China; College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China.
Sci Total Environ. 2024 Jan 10;907:167934. doi: 10.1016/j.scitotenv.2023.167934. Epub 2023 Oct 18.
Compound drought and heatwaves (CDH) have garnered increasing attention because concurrent extreme events can exacerbate the harmful impacts caused by univariate extremes. However, various severities in CDH events and their relationships with sea surface temperature (SST) variations in China remain little understood. Here, we accurately identify CDH events and multi-aspect of characteristics using the standardized precipitation evapotranspiration index (SPEI) and the excess heat factor (EHF) during the extended summer (May-September) of 1961-2017. The evolution of multifaceted characteristics of CDH and their association with SST variation are further explored. The results suggest that the number, frequency, duration and intensity of regional CDH events show heterogeneous spatial patterns, with a significant increasing trend. A consistent abrupt transition in CDH characteristics averaged over China occurred in the period of 1993-1996. Mild and moderate CDHs occur more commonly in Northwest and North China, whereas severe CDHs are mainly found in central and eastern regions. Mild and moderate CDHs are more susceptible to SST modes than severe CDH, and there are strong positive correlations between mild and moderate CDH characteristics and SST variations in the northwest and northern regions. Compared to El Niño-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD) plays a dominant role in the intensifications of mild and moderate CDH events. Regionally, the northwest and north have experienced longer, more frequent and severe CDH events during the positive phase of IOD. These findings reveal the divergent evolutions in CDH characteristics with various severities and inconsistent impacts of different SST modes on the compound events.
复合型干旱和热浪（CDH）已受到越来越多的关注，因为同时发生的极端事件会加剧单一极端事件所造成的有害影响。然而，中国CDH事件的各种严重程度及其与海表面温度（SST）变化之间的关系仍鲜为人知。在此，我们利用标准化降水蒸散指数（SPEI）和过剩热因子（EHF），准确识别了1961 - 2017年延长夏季（5 - 9月）期间的CDH事件及其多方面特征。进一步探讨了CDH多方面特征的演变及其与SST变化的关联。结果表明，区域CDH事件的数量、频率、持续时间和强度呈现出异质性的空间格局，且有显著的增加趋势。1993 - 1996年期间，中国CDH特征出现了一致的突变。轻度和中度CDH在中国西北和华北地区更为常见，而重度CDH主要出现在中部和东部地区。与重度CDH相比，轻度和中度CDH更容易受到SST模态的影响，且在西北和北方地区，轻度和中度CDH特征与SST变化之间存在很强的正相关。与厄尔尼诺 - 南方涛动（ENSO）相比, 印度洋偶极子（IOD）在轻度和中度CDH事件的增强中起主导作用。在区域上，IOD正相位期间，西北和北方经历了更长、更频繁和更严重的CDH事件。这些发现揭示了不同严重程度的CDH特征的不同演变以及不同SST模态对复合型事件的影响不一致。
