The Role of the Ocean for the Development of Heat Waves over Europe

European heat waves are becoming more and more severe under global warming. The frequency and duration of heat waves are very likely to further increase under future climate conditions over most land areas. To improve the predictability of such extreme events, it is important to understand their driving mechanisms better.

Although earlier work hints at a connection between North Atlantic sea surface temperatures (SSTs) and the occurrence of European heat waves, the role of the ocean in shaping heat waves is still not fully understood. Here, we investigate the effect of the 2018 SST pattern, which was characterized by negative anomalies in the North Atlantic, on European heat wave characteristics.

Using the Flexible Ocean and Climate Infrastructure (FOCI) model we conducted two 100-year long AMIP-like model experiments: one that employs the observed global 2018 SST and sea ice patterns as a boundary forcing and another one that differs only in the North Atlantic SST field, for which we removed the cold SST anomaly. Comparing these two experimental settings, we find that cold North Atlantic SST anomalies can favor heat wave conditions especially over the most eastern part of the European continent.