Sea Spray Impacts on Tropical Cyclone Olwyn Using a Coupled Atmosphere‐Ocean‐Wave Model. Issue 8 (18th August 2022)

• Record Type: Journal Article
• Authors: Xu, Xingkun; Voermans, Joey Jeff; Moon, Il‐Ju; Liu, Qingxiang; Guan, Changlong; Babanin, Alexander V.
• Is Part Of: Journal of geophysical research. Volume 127:Issue 8(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-18
• Subjects: sea spray -- tropical cyclone Olwyn -- air‐sea fluxes -- ocean waves; Oceanography -- Periodicals; 551.4605
• DOI: 10.1029/2022JC018557
• Languages: English
• ISSNs: 2169-9275

Abstract

Abstract: Extreme 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. Plain Language Summary: Large quantities of sea spray droplets are generated at the ocean surface and released into the air under extreme marine weather conditions. Even though sea spray plays an important role in the transfer of heat, moisture, and momentum between the air and ocean surface, its true impact remains uncertain in tropical cyclone (TC) modeling. In this study, we include a novel description of sea spray generation into an atmosphere‐ocean‐wave coupled model to investigate the impacts of sea spray on the development of TC Olwyn. In comparison to a simulation without sea spray, the errors of wind speed and wave height of the modeled TC Olwyn are considerably reduced when sea spray is considered. This improvement is expected to be from the impacts of sea spray on the structure of the TC Olwyn. As sea spray has significant effects on the atmospheric and oceanic environments, our results suggest that sea spray generations need to be included in current TC forecasting models. Key Points: Implementation of wind‐wave dependent sea spray parameterizations into the atmosphere‐ocean‐wave coupled model The simulation error of U 10 and H s for tropical cyclone (TC) Olwyn is significantly reduced by introducing the sea spray The sea spray plays a critical role in the development and intensification of TC Olwyn, and underlying sea surface temperature cooling