Details

Autor(en) / Beteiligte

• Jiménez‐Esteve, Bernat
• Domeisen, Daniela I.V.

Titel

The role of atmospheric dynamics and large‐scale topography in driving heatwaves

Ist Teil von

• Quarterly journal of the Royal Meteorological Society, 2022-07, Vol.148 (746), p.2344-2367

Ort / Verlag

Chichester, UK: John Wiley & Sons, Ltd

Erscheinungsjahr

2022

Link zum Volltext

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• Heatwaves are weather events characterized by extreme near‐surface temperature anomalies that persist for several days, and therefore lead to catastrophic impacts on natural ecosystems, agriculture, human health, and economies. Different physical processes can contribute to the temperature anomaly associated with heatwaves. Previous studies have shown that increased solar radiation and adiabatic heating associated with blocking systems and local land–atmosphere coupling are important drivers of summer heatwaves. Less is known about the fundamental role of atmospheric large‐scale dynamics and topography in generating heatwaves. Here, we perform idealized model simulations where all physical parameterisations are substituted by a simple zonally symmetric temperature relaxation scheme. This allows us to characterize the dynamical processes involved in the life cycle of heatwaves occurring at different latitudes. We find that blocking plays an active role in the life cycle of high‐ and midlatitude heatwaves, while blocking is less relevant for low‐latitude heatwaves. Rossby‐wave packets are the dominant drivers for midlatitude heatwaves, with horizontal advection being the main mechanism leading to heat extremes. Heatwaves exhibit a higher persistence and frequency near the pole and Equator compared with the midlatitudes, but a higher intensity in the midlatitudes compared with higher and lower latitudes. Topography located along the midlatitude jet has the largest impact on the heatwave distribution around the planet, resulting in increased heatwave frequency upstream for moderate topographic forcing and a circumglobal increase for topographic elevations above 6 km. Identifying the most relevant processes driving heatwaves can potentially benefit the prediction and representation of extreme events in operational weather and climate forecast systems. Heatwaves are weather events characterized by extreme near‐surface temperature anomalies that persist for several days. By performing idealized model simulations, we study the underlying role of atmospheric dynamics and topography on the life cycle of heatwaves at different latitudes. We find that the dynamics of midlatitude heatwaves are strongly associated with the zonal propagation of Rossby‐wave packets, while atmospheric blocking dominates at higher latitudes. Topography has an effect on the longitudinal location of heatwaves.