Sea Spray Impacts on Tropical Cyclone Olwyn Using a Coupled Atmosphere‐Ocean‐Wave Model

Abstract

AbstractExtreme marine weather enhances the production of sea spray droplets which, in turn, affect the air‐sea fluxes. Despite the ability of sea spray to modulate air‐sea interaction processes, it remains under‐represented in tropical cyclone (TC) forecasting modeling. In this study, impacts of sea spray on the atmospheric and oceanic environments of TC Olwyn are investigated. This is achieved by high‐resolution nested simulations using an air‐sea‐wave model coupled with a sea spray production model. We compared two different sea spray models: a wave‐Reynolds‐number‐dependent model, and a wave‐steepness‐dependent spray model. By including a sea spray model, the root mean square error in the simulated TC Olwyn 10 m wind and significant wave height are significantly reduced by up to 30% and 26%, respectively, in comparison to the baseline simulation without spray. This improvement is because sea spray decreases air‐sea heat fluxes at larger radii of TC, and decreases air‐sea heat fluxes at smaller radii of TC. In contrast to the simulated results without sea spray, sea spray increases the air‐sea heat (sensible + latent) energy transfer and intensifies TC Olwyn. Sea spray also triggers stronger upper‐ocean mixing and strengthens the TC‐induced sea surface temperature cooling. Our results thus imply that sea spray critically impacts the atmosphere and ocean conditions during extreme marine weather and thus needs to be considered explicitly in TC forecasting modeling.