q 2001 American Meteorological Society The Impact of Sea Spray Evaporation in a Numerical Weather Prediction Model

Strong winds above the sea lead to large amounts of spray in the lowest part of the boundary layer. Through their evaporation, spray droplets influence the exchange of sensible and latent heat between sea and air. In this study, the impact of spray on the atmosphere is investigated using the numerical weather prediction high-resolution limited-area model HiRLAM. The effect of spray is taken into account via modified surface heat fluxes. The impact on forecasts is then investigated in two case studies of intense midlatitude storms. A general consequence of spray is a significantly cooler and moister surface layer. Indirect effects are reported as well, such as enhanced precipitation, and associated midlevel latent heat release. The second case study, which deals with a rapidly deepening depression, indicates that including spray leads to a marginal intensification of the depression. 1