Heat Budget of the Upper Ocean Under Light Winds

Abstract

The heat budget of a small region (?2 km?2 km) near the coast of northwest Africa was investigated during a 3-day period in March 1974 when light winds (?2 m s?1) occurred. Horizontal advection and diffusion of heat were negligible, and the local change in heat content resulted from the net radiative and evaporative flux at the sea surface. Diurnal heating produced surface temperature ranges of 0.9, 1.1 and 1.4°C for each of the 3 days. The exponential decrease of the diurnal heat wave with depth was used to estimate the vertical eddy thermal conductivity of the upper 10 m; values of approximately 10?3 m?2 s?1 were obtained.