Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
Sci Total Environ. 2024 Nov 1;949:175113. doi: 10.1016/j.scitotenv.2024.175113. Epub 2024 Jul 29.
Compound drought and heat events (CDHEs), which are frequently occurring compound extreme climate events, have garnered considerable attention because of their detrimental effects on ecosystems. However, the intricacies of the spatial and temporal distributions of different durations of compound events, along with the variability in vegetation responses remain unclear. Here, we delineated the CDHEs based on meteorological observation data and investigated the spatial and temporal characteristics of CDHEs from 1993 to 2020 using the Theil-Sen trend test and Mann-Kendall nonparametric test. Furthermore, we utilized sliding correlation analysis to evaluate the impacts of CDHEs on vegetation among different climatic regions and ecosystems. Our findings indicate significant increasing trends in both the frequency and persistence of CDHEs from 1993 to 2020. The average trend of CDHEs frequency across different duration periods amounted to 13.80 %/decade. The fractional contribution of CDHEs lasting more than three days exhibited a significant increase, with an average trend of 2.00 %/decade. We also observed that vegetation is most significantly affected by compound events lasting 5-9 days. During the study period, the geographical extent of vegetation significantly impacted by CDHEs expanded by 0.89 %, correlation strength increased by 0.02, and lag time decreased by 0.25 months. These insights highlight the growing impact of CDHEs on vegetation under climate change, improving our understanding of vegetation responses to these compound events.
复合干旱和热事件（CDHEs）是经常发生的复合极端气候事件，由于它们对生态系统的不利影响而引起了相当大的关注。然而，不同持续时间的复合事件的空间和时间分布的复杂性以及植被响应的可变性仍不清楚。在这里，我们根据气象观测数据划定了 CDHEs，并利用 Theil-Sen 趋势检验和 Mann-Kendall 非参数检验研究了 1993 年至 2020 年 CDHEs 的时空特征。此外，我们利用滑动相关分析评估了 CDHEs 在不同气候区和生态系统中对植被的影响。我们的研究结果表明，1993 年至 2020 年，CDHEs 的频率和持续时间都呈现出显著的增加趋势。不同持续时间的 CDHEs 频率的平均趋势为 13.80%/decade。持续时间超过三天的 CDHEs 的分数贡献呈现出显著增加的趋势，平均趋势为 2.00%/decade。我们还观察到，植被受持续 5-9 天的复合事件的影响最为显著。在研究期间，受 CDHEs 显著影响的植被地理范围扩大了 0.89%，相关强度增加了 0.02，滞后时间减少了 0.25 个月。这些研究结果强调了在气候变化下 CDHEs 对植被的影响越来越大，提高了我们对植被对这些复合事件的响应的理解。
