Sixfold Increase in Historical Northern Hemisphere Concurrent Large Heatwaves Driven by Warming and Changing Atmospheric Circulations
Sixfold Increase in Historical Northern Hemisphere Concurrent Large Heatwaves Driven by Warming and Changing Atmospheric Circulations
复制标题
DOI：
10.1175/jcli-d-21-0200.1
复制
发表时间：
2022-02-01
影响因子：
4.9
通讯作者：
Singh, Deepti
中科院分区：
文献类型：
--
作者：
Rogers, Cassandra D. W.;Kornhuber, Kai;Singh, Deepti
同时影响多个地区的热浪（称为并发热浪）对各种自然和社会系统构成复合威胁，包括全球食物链，应急响应系统和再保险行业。虽然人为气候变化正在增加大多数地区的热浪风险，但变暖和环流变化之间的相互作用产生并发热浪仍然没有得到充分研究。在这里，我们量化了北方半球中高纬度地区暖季[5月至9月（MJJAS）]期间并发热浪的历史（1979-2019）趋势。我们发现并发热浪的平均空间范围显着增加了46%，其最大强度增加了17%，其频率增加了约6倍。使用自组织地图，我们确定大尺度环流模式（300百帕）与特定的并发热浪配置整个北方半球地区。我们发现，所观察到的特定环流模式的频率变化优先增加特定地区并发热浪的风险。连接北美东部、东欧和北方、亚洲部分地区以及巴伦支海和喀拉海的同时热浪的模式显示频率增加最多（类似于每十年增加5.9天）。我们还量化了环流模式变化和变暖对整体观测到的同时热浪日频率趋势的相对贡献。虽然变暖对增加并发热浪频率有着主要和积极的影响，但环流模式的变化有着不同的影响，每十年增加0.8个并发热浪日。识别同时热浪风险升高的地区并了解其驱动因素对于评估相互关联的社会系统的预计气候风险和促进气候变化中的区域准备是必不可少的。重要性声明：热浪对人类健康、生态系统和人类系统构成重大威胁。同时影响多个地区的热浪可能会加剧这种威胁。例如，多个粮食生产地区同时遭受与高温有关的作物损害可能导致全球粮食短缺。我们评估了同时发生的大热浪的最近变化。这种同时发生的热浪的可能性是40年前的7倍。它们也更热，影响更大的区域。其发生率的增加主要是由于全球变暖导致的基线温度升高，但天气模式的变化导致欧洲部分地区，美国东部和亚洲的不成比例的增加。因此，更好地了解天气模式变化的驱动因素对于了解未来并发热浪的特征及其影响至关重要。
Simultaneous heatwaves affecting multiple regions (referred to as concurrent heatwaves) pose compounding threats to various natural and societal systems, including global food chains, emergency response systems, and reinsurance industries. While anthropogenic climate change is increasing heatwave risks across most regions, the interactions between warming and circulation changes that yield concurrent heatwaves remain understudied. Here, we quantify historical (1979-2019) trends in concurrent heatwaves during the warm season [May-September (MJJAS)] across the Northern Hemisphere mid- to high latitudes. We find a significant increase of similar to 46% in the mean spatial extent of concurrent heatwaves and similar to 17% increase in their maximum intensity, and an approximately sixfold increase in their frequency. Using self-organizing maps, we identify large-scale circulation patterns (300 hPa) associated with specific concurrent heatwave configurations across Northern Hemisphere regions. We show that observed changes in the frequency of specific circulation patterns preferentially increase the risk of concurrent heatwaves across particular regions. Patterns linking concurrent heatwaves across eastern North America, eastern and northern Europe, parts of Asia, and the Barents and Kara Seas show the largest increases in frequency (similar to 5.9 additional days per decade). We also quantify the relative contributions of circulation pattern changes and warming to overall observed concurrent heatwave day frequency trends. While warming has a predominant and positive influence on increasing concurrent heatwave frequency, circulation pattern changes have a varying influence and account for up to 0.8 additional concurrent heatwave days per decade. Identifying regions with an elevated risk of concurrent heatwaves and understanding their drivers is indispensable for evaluating projected climate risks on interconnected societal systems and fostering regional preparedness in a changing climate.SIGNIFICANCE STATEMENT: Heatwaves pose a major threat to human health, ecosystems, and human systems. Simultaneous heatwaves affecting multiple regions can exacerbate such threats. For example, multiple food-producing regions simultaneously undergoing heat-related crop damage could drive global food shortages. We assess recent changes in the occurrence of simultaneous large heatwaves. Such simultaneous heatwaves are 7 times more likely now than 40 years ago. They are also hotter and affect a larger area. Their increasing occurrence is mainly driven by warming baseline temperatures due to global heating, but changes in weather patterns contribute to disproportionate increases over parts of Europe, the eastern United States, and Asia. Better understanding the drivers of weather pattern changes is therefore important for understanding future concurrent heatwave characteristics and their impacts.