Dynamics and characteristics of dry and moist heatwaves over East Asia

The increasing frequency of heatwaves over East Asia (EA) is impacting agriculture, water management, and people's livelihood. However, the effect of humidity on high-temperature events has not yet been fully explored. Using observations and future climate change projections conducted with the latest generation of Earth System models, we examine the mechanisms of dry and moist heatwaves over EA. In the dry heatwave region, anticyclonic circulation has been amplified after the onset of heatwaves under the influence of the convergence of anomalous wave activity flux over northern EA, resulting in surface warming via adiabatic processes. In contrast, the moist heatwaves are triggered by the locally generated anticyclonic anomalies, with the surface warming amplified by cloud and water vapor feedback. Model simulations from phase six of the Coupled Model Intercomparison Project projected display intensification of dry heatwaves and increased moist heatwave days in response to projected increases in greenhouse gas concentrations.

Automated summary

This study explores the mechanisms of dry and moist heatwaves over East Asia using observations, climate change projections, and new generation Earth System models. The research finds that dry heatwaves are amplified by the convergence of wave activity over the region, resulting in surface warming. On the other hand, moist heatwaves are triggered by local anticyclonic anomalies and amplified by cloud and water vapor feedback. Model simulations project an intensification of dry heatwaves and an increase in moist heatwave days in response to rising greenhouse gas concentrations.