复旦大学左志燕团队发现陆气耦合加剧了未来白天夜间同时出现极端高温的风险。2025年3月12日出版的《中国科学：地球科学》发表了这项成果。

白天和夜间极端高温的复合热浪（以下简称复合热浪）在全球范围内频繁发生，威胁着人类健康和生态系统。陆地-空气耦合（LAC）已被确定为放大纯白天热浪强度和频率的关键因素，但尚不清楚其是否会影响复合热浪的频率和结构。

使用CMIP6模型，研究组发现，在1995-2099年期间，LAC将导致全球大多数地区在复合热浪事件中同时出现的白天-夜间极端高温和独立高温天数的增加，而独立高温夜晚的减少。在高排放情景下，复合热浪结构的这种变化在长期未来（2080-2099）尤为明显。随着温室气体排放的失控，LAC的增强似乎加剧了白天地表感热通量和夜间地表上升长波辐射，从而提高了近地表温度。

随着更多的非热日/夜、独立的热日和热夜转化为同时发生的日间-夜间极端高温，短期复合热浪将合并为较长的热浪，加剧其风险。在长期未来的复合热浪期间，由LAC引起的日间-夜间同时出现的极端高温强度可能分别是北美中部、南美北部、地中海沿岸和澳大利亚北部等热点地区历史时期的39倍、101倍、42倍和7倍。相比之下，在其他情况下，LAC的有限影响可能会导致短期复合热浪的频率更高，这反过来又会增加复合热浪的发生频率。该研究结果为非减排情景下与复合热浪相关的政策决策提供了科学依据。

附：英文原文

Title: Land-air coupling exacerbates the future risk of concurrent daytime-nighttime hot extremes

Author: Kaiwen Zhang, Yingxu Zhan, Zhiyan Zuo, Lulei Bu, Meiyu Chang, Liang Qiao

Issue&Volume: 2025/03/12

Abstract: Compound heatwaves with both daytime and nighttime hot extremes (hereafter compound heatwaves) have been occurring frequently worldwide, threatening human health and ecosystems. Land-air coupling (LAC) has been identified as a key factor in amplifying the intensity and frequency of purely daytime heatwaves, but it remains unclear whether it affects the frequency and structure of compound heatwaves. Here, using CMIP6 models, we reveal that LAC will cause an increase in concurrent daytime-nighttime hot extremes and independent hot days, with a decrease in independent hot nights during a compound heatwave event in most areas of the globe during 1995–2099. This change in the structure of compound heatwaves is particularly pronounced in the long-term future (2080–2099) under the high-emission scenario. With the uncontrolled greenhouse-gases emissions, enhanced LAC appears to intensify the daytime surface sensible heat flux and nighttime surface upwelling longwave radiation, thereby raising near-surface temperatures. With more non-hot days/nights, independent hot days and nights converted into concurrent daytime-nighttime hot extremes, short-term compound heatwaves will be merged into longer ones, exacerbating their risks. The intensity of concurrent daytime-nighttime hot extremes due to LAC during a compound heatwave in the long-term future maybe 39, 101, 42, and 7 times higher than in the historical period in hotspots such as central North America, northern South America, the Mediterranean coast, and northern Australia, respectively. In contrast, under other scenarios, the limited influence of LAC may cause a higher frequency of short-term compound heatwaves, which in turn would increase the frequency of compound heatwaves. Our results provide a scientific foundation for the policy decisions related to compound heatwaves under the non-emission-reduction scenarios.

DOI: 10.1007/s11430-024-1519-2

Source: https://www.sciengine.com/SCES/doi/10.1007/s11430-024-1519-2