Coupled Ocean-Cloud-Resolving Simulations of the Air–Sea Interaction over the Equatorial Western Pacific

Abstract

A cloud-resolving model coupled to an ocean model with high vertical resolution is used to investigate air?sea interactions in 10-day long simulations. Modeled fields showed good agreement with two different convective regimes during the Tropical Ocean Global Atmosphere Coupled Ocean?Atmosphere Research Experiment (TOGA COARE) Intensive Observing Period. The model simulates the formation of precipitation-produced, stable freshwater lenses at the top of the ocean mixed layer, with a variety of horizontal dimensions and lifetimes. The simulated fresh anomalies show realistic features, such as a positive correlation between salinity and temperature, the development of a surface jet in the direction of the wind, and, as a consequence, downwelling (upwelling) on its downwind (upwind) edge. The dataset generated by the coupled model is used to evaluate the contribution from several factors (ocean currents, gustiness, and correlations between wind speed and air temperature, wind speed and water vapor mixing ratio, and wind speed and SST) to the surface heat fluxes. Gustiness was shown to be a major contribution to the simulated surface heat fluxes, especially when convection is active. In a multiday average, the contributions from the other effects (currents and wind speed?air temperature, wind speed?water vapor mixing ratio, and wind speed?SST correlations) are small; however, they cannot be neglected under certain circumstances.