Three-dimensional insight into heat waves in EURO-CORDEX regional climate models

Heat waves are considered one of the most hazardous climate extremes in relation to climate change. To better understand their driving mechanisms in CORDEX regional climate models (RCMs) over Middle Europe, we employ a recently introduced approach to study heat waves as three-dimensional phenomena (Lhotka & Kyselý 2024). We classify them based on their vertical cross-sections of temperature anomalies into near-ground, lower-tropospheric, mid-tropospheric, and vertically extensive types. We show that even driven by the reanalysis, most RCMs tend to simulate substantially more lower-tropospheric heat waves than those located near the surface, which is in contrast to reference data from ERA5. This bias is associated with overly frequent southerly flow that is excessively warm especially at the lower-tropospheric level. We also identify large differences among the RCMs in simulations of near-ground and vertically extensive heat wave types, which are possibly related to deficiencies in links between easterly flow and those heat wave types.

Lhotka, O., Kyselý, J. Three-dimensional analysis reveals diverse heat wave types in Europe. Commun Earth Environ 5, 323 (2024). https://doi.org/10.1038/s43247-024-01497-2