1508. First Scientific Definition of “Heat Dome” Proposed to Improve Understanding and Prediction of Extreme Heat Events

A heat dome refers to a meteorological phenomenon in which a persistent high-pressure system traps heat in the lower atmosphere, leading to prolonged and widespread periods of exceptionally high temperatures. While the term has become increasingly common in media coverage of record-breaking heatwaves across North America, Europe, and other regions, no formal scientific definition had previously been established.

In this study, researchers analyzed meteorological data from North America spanning 1940–2025 and developed a quantitative definition of a heat dome as a combination of a strong positive anomaly in the 500-hPa geopotential height field and concurrent extreme near-surface temperatures. Using this framework, they found that many of the most severe extreme heat events in North America were associated with heat dome conditions. However, the analysis also demonstrated that not all heatwaves are generated by heat domes, indicating that multiple mechanisms can lead to extreme heat.

The study further showed that during heat dome events, anticyclonic circulation aloft enhances subsidence, suppresses cloud formation, and increases incoming solar radiation, thereby intensifying surface warming. Quantifying these atmospheric circulation characteristics may improve the ability to identify and evaluate the drivers of extreme heat events.

Although the analysis focused on North American events, the authors note that severe heatwaves have become increasingly common across Asia, Europe, Africa, and other regions in recent years. They argue that a clear scientific definition of heat domes can provide a common framework for heatwave research, support climate model evaluation, and facilitate comparisons of extreme heat risks across regions and time periods.

Extreme heat affects not only human health but also water resources, agricultural production, energy demand, and broader socioeconomic systems. By providing a rigorous scientific definition of a widely used concept, this study contributes to improving future assessments of climate change impacts and the development of adaptation strategies.

(Reference)
Overland, J. E., Kretschmer, F., Smith, C. A. et al. Toward a Scientific Definition of Heat Dome Events. Weather and Climate Extremes (2026). https://doi.org/10.1016/j.wace.2026.100913

Contributor: IIYAMA Miyuki, Strategic Coordination Office