A Model for Air–Sea Interaction Bulk Coefficient over a Warm Mature Sea under Strong Wind

Abstract

A boundary layer model for evaluating sensible and latent heat fluxes over a mature sea accounting for sea spray effects at wind speeds of up to 28 m s?1 is presented. Heat exchange across the ocean surface controls the development of tropical cyclones, and Emanuel?s theory suggests that the ratio of the exchange coefficient of total enthalpy to the drag coefficient should be greater than 0.75 to maintain the intensity of tropical cyclones. However, traditional bulk algorithms predict a monotonic decrease in this ratio with increasing wind speed, giving a value of less than 0.5 under tropical cyclone conditions. The present model describes a decrease in the ratio with increasing wind speed under weak to moderate winds (<20 m s?1), and a plateau at approximately 0.7 under strong winds (>20 m s?1).