Impact of sea spray-mediated heat fluxes on polar low development

Abstract

Sea spray, originating from wave breaking under high wind conditions, can significantly affect turbulent heat fluxes at the air–sea interface. Even though polar lows (PLs) can become extreme weather features with gale-force wind, the impact of sea spray on their development has rarely been investigated and is not considered in operational forecast models. In this study, the impact of sea spray on the development of two PLs over the Barents Sea is studied based on sensitivity experiments with an atmosphere–wave coupled model, where the spray-mediated heat fluxes are parameterized. The results show that the impact of sea-spray-mediated heat fluxes on PL development is sensitive to the surface wind speed. In the case of the stronger PL, the higher surface wind speed results in significantly higher spray-mediated heat fluxes. Consequently, these spray-mediated heat fluxes intensify the convection and diabatic heating of the PL, resulting in its intensification. In comparison, the case with a weaker PL experiences less sea spray production and lower spray-mediated heat fluxes due to its weaker surface wind speeds. Overall, we find that spray-mediated sensible heat fluxes play an important role in the development of PLs, while the latent heat fluxes induced by sea spray have a relatively minor impact.