Large-Eddy Simulation of Sea Spray Impacts on Fluxes in the High-Wind Boundary Layer

Abstract

The exchange of enthalpy and momentum at the air-sea interface is an important process in tropical cyclone (TC) development and intensification, and the effects of sea spray have long been uncertain, particularly at high wind speeds. Here we use a coupled large-eddy simulation and Lagrangian cloud model to run high-resolution simulations of an idealized, spray-laden TC boundary layer. Simulations are performed with and without spray generation, using a realistic sea spray generation function over wind speeds relevant to TCs. We show that CD is not affected by spray droplets at 10-m wind speeds up to 48 m s−1. CE and CH are modified during an initial transient adjustment stage, but quickly relax back to their unladen values due to surface layer saturation. This relaxation occurs faster for higher winds, because the increased spray concentration more rapidly saturates the surface layer.