Improved European heat event simulation by resolving oceanic-mesoscale eddies

Owing to the rapid increase of European heat event occurrences over the past decades, the understanding of their physical drivers has become increasingly important for the scientific community. Recently, it has been shown that cold North Atlantic sea surface temperatures (SSTs) are strongly linked to European heat events such as in summer 2015 and 2018. Thereby, an accurate representation of this connection in climate models is crucial for a more realistic European heat event simulation. Here, we investigate the connection by employing seven global coupled climate models, from which six models are embedded in the High Resolution Model Intercomparison Project (HighResMIP). High-resolution versions of these models capture mesoscale eddies, thus enabling to study their impact onto the (North Atlantic SST- European summer temperature extremes) connection. Our results show that high-resolution model versions better capture the North Atlantic trough and the downstream ridge anomalies over central Europe, although still underestimated in intensity and duration compared to observations. Improvements in high-resolution configurations are due to the increased ocean model resolution, which reduces the North Atlantic surface biases and improves air-sea interactions, thus having implications for the prediction and projection of climate extremes in the North Atlantic-European region.