Local mechanisms for global daytime, nighttime, and compound heatwaves

作者：Sijia Wu, Ming Luo, Rui Zhao, Jing Li, Peng Sun, Zhen Liu, Xiaoyu Wang, Peng Wang, Hui Zhang · 发表于：npj Climate and Atmospheric Science · 年份：2023 · DOI：10.1038/s41612-023-00365-8 · 被引用次数：128 · 研究领域：Climate variability and models、Meteorological Phenomena and Simulations、Climate Change and Health Impacts

Abstract Heatwaves impose serious impacts on ecosystems, human health, agriculture, and energy consumption. Previous studies have classified heatwaves into independent daytime, independent nighttime, and compound daytime-nighttime types, and examined the long-term changes in the three types. However, the underlying mechanisms associated with the variations in different heatwave types remain poorly understood. Here we present the first investigation of the local physical processes associated with the daytime, nighttime, and compound heatwaves over the global land during 1979–2020. The results show that three heatwave types occur frequently and increasingly in most regions worldwide. Nighttime and compound heatwaves exhibit stronger increases in both frequency (the yearly number of the events) and fraction (the ratio of the yearly number of one heatwave type to the total yearly number of all types) than daytime heatwaves. Composite diagnostic analyses of local meteorological variables suggest that daytime heatwaves are associated with increased solar radiation under dry conditions and reduced cloud cover and humidity under a clear sky. In contrast, nighttime heatwaves are typically accompanied by moist conditions with increases in cloud fraction, humidity, and longwave radiation at night. These synoptic conditions for daytime and nighttime heatwaves are combined to contribute to compound heatwaves. Local divergences and moisture fluxes responsible for different heatwaves are fu...