Surface and bottom marine heatwave characteristics in the Barents Sea: a model study

Abstract. Anomalously warm oceanic events, often termed marine heatwaves (MHWs), can potentially impact the ecosystem in the affected region and have therefore become a hot topic for research in recent years. Determining the intensity and spatial extent of marine heatwaves, however, depends on the definition and climatological average used. Moreover, the stress applied by the heatwave to the marine ecosystem will depend on which component of the ecosystem is considered. Here, we utilize a model reanalysis (1991–2022) to explore the frequency, intensity, and duration of marine heatwaves in the Barents Sea, as well as regional heterogeneities. We find that major marine heatwaves are rather coherent throughout the region, but surface marine heatwaves occur more frequently while heatwaves on the ocean floor have a longer duration. Moreover, we investigate the sensitivity to the choice of climatological average length when calculating marine heatwave statistics. Our results indicate that severe marine heatwaves may become more frequent in a future Barents Sea due to ongoing climate change.