Based on the observational dataset SA-OBS and model outputs from the Community Earth System Model Large Ensemble project, this study investigates heatwaves in Southeast Asia in the current and future warmer climate. A heatwave is detected when the daily maximum temperature exceeds the 90th percentile threshold at each grid for at least three consecutive days. Three characteristics describing the frequency, duration, and amplitude of heatwaves are examined, including the sum of heatwave days per year (HWF) satisfying the heatwave definition, the length of the longest yearly heatwave event (HWD), and the hottest amplitude of the hottest yearly heatwave event (HWA). Results indicate that increased global warming is associated with substantial changes in heatwave characteristics over Southeast Asia, with more frequent heatwaves, longer heatwave duration, and higher extreme temperatures. The increase in HWA has a linear growth against global warming levels with distinct regional differences between the Maritime Continent and the Indochina Peninsula due to their different heat content of lower atmospheric boundaries. In contrast, those in HWF and HWD have nonlinear growth characteristics. The projected warmer future tends to be associated with a higher risk ratio value with the occurrence of rarer extreme heatwaves relative to the current climate. These results reiterate the potential risks of extreme regional heatwaves if global warming is unrestricted.

中文翻译：

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东南亚的热浪及其在温暖世界中的变化

基于观测数据集 SA-OBS 和社区地球系统模型大型集合项目的模型输出，本研究调查了东南亚在当前和未来气候变暖的情况下的热浪。当每个网格的每日最高温度至少连续三天超过第 90 个百分位数阈值时，就会检测到热浪。研究了描述热浪频率、持续时间和幅度的三个特征，包括满足热浪定义的每年热浪天数 (HWF)、最长年度热浪事件 (HWD) 的长度和最热的最热幅度年度热浪事件 (HWA)。结果表明，全球变暖加剧与东南亚热浪特征的重大变化有关，热浪更频繁，更长的热浪持续时间和更高的极端温度。HWA 的增加与全球变暖水平呈线性增长，海洋大陆和印度支那半岛之间由于较低大气边界的热含量不同而具有明显的区域差异。相比之下，HWF 和 HWD 中的那些具有非线性增长特性。与当前气候相比，预计的更温暖的未来往往与更高的风险比值相关联，并且会发生罕见的极端热浪。如果全球变暖不受限制，这些结果重申了极端区域热浪的潜在风险。HWA 的增加与全球变暖水平呈线性增长，海洋大陆和印度支那半岛之间由于较低大气边界的热含量不同而具有明显的区域差异。相比之下，HWF 和 HWD 中的那些具有非线性增长特性。与当前气候相比，预计的更温暖的未来往往与更高的风险比值相关联，并且会发生罕见的极端热浪。如果全球变暖不受限制，这些结果重申了极端区域热浪的潜在风险。HWA 的增加与全球变暖水平呈线性增长，海洋大陆和印度支那半岛之间由于较低大气边界的热含量不同而具有明显的区域差异。相比之下，HWF 和 HWD 中的那些具有非线性增长特性。与当前气候相比，预计的更温暖的未来往往与更高的风险比值相关联，并且会发生罕见的极端热浪。如果全球变暖不受限制，这些结果重申了极端区域热浪的潜在风险。