Relation of Sea Waves to the Atmospheric Cyclone Activity in the Northern Hemisphere according to the ERA5 Reanalysis Data

Abstract— Based on the ERA5 reanalysis data for the period 1979–2021, the authors have quantified the seasonal and regional connections between significant wave heights and changes in cyclone activity in the atmosphere of the Northern Hemisphere. The contribution of extratropical cyclones to the formation of the corresponding features and variations of sea waves is evaluated. The maxima of the extreme sea wave occurrence frequency in winter and summer corresponds to sea areas with an increased frequency of cyclones, in particular, over the Pacific and Atlantic oceans. It has been found that the contribution of extratropical cyclones to the generation of significant wave heights reaches 70% in winter and 50% in summer. The largest contribution is associated with intense cyclones: 90% in winter and 40% in summer.