Parametrization of tropical ocean heat flux

Abstract A heat‐flux scheme, based on the assumption of a constant relative humidity and air‐sea temperature difference, is tested for the tropical oceans. It is compared with heat fluxes over the Pacific Ocean, determined by empirical formulae and maritime observations, both for long‐term monthly‐mean fluxes and for interannual variations in heat fluxes over the equatorial Pacific Ocean. It is shown that the differences in latent heat flux between values obtained by the scheme and those calculated from maritime observations are generally no greater than the uncertainty in the bulk aerodynamic method. the method is also shown to be successful in reproducing the interannual variation in surface heat loss in the eastern Pacific Ocean, though the variability is less than that obtained from maritime observations in the coastal upwelling zone adjacent to South America. Finally, the sensitivity of the heat‐flux scheme to sea surface temperature, for wind speeds typical over the tropical Pacific Ocean, is compared to other schemes. It is shown that the sensitivity coefficient is a function of both wind speed and sea surface temperature, and has values in the range 2‐16 W m −2 K −1 for the tropical ocean.