Sea Subsurface Temperature Research Articles

The temperature difference across the cool skin of the ocean

The temperature difference ΔT across the cool skin of the ocean was determined from radiometric measurements of surface brightness temperature and conventional measurements of temperature at a depth of 1 m. Eleven days of measurements were made from the R/P Flip in February 1974 about 800 miles north of Hawaii (35°N, 155°W). The surface brightness temperature was corrected for nonblackness of the surface to obtain an estimate of the true surface temperature. The constant λ in Saunders' (1967a) formula, ΔT = λvQ/kU* was found to be λ = 6.5±0.6, where v is kinematic viscosity, Q the upward heat flux just below, the interface, k the thermal conductivity, and U* the friction velocity. The constant is independent of wind speed for winds ranging from 3 to 11 m/s. The use of subsurface rather than surface temperature in the bulk aerodynamic formulas results in an increase in the sum of the sensible and latent heat fluxes equal to 4‐5% of Q. However, the percentage change in sensible and latent heat fluxes may be much greater. Spectra of surface and subsurface sea temperature exhibit a peak at low frequencies and fall off approximately proportional to ƒ−3/2; with increasing frequency ƒ. The variability of sea surface temperature was caused about equally by the variability of subsurface temperature and the variability of ΔT. Caution should therefore be exercised in the interpretation of radiometric surface temperature measurements as representative of subsurface temperature.

On moisture-flux parameterization

From direct measurements of vertical fluxes of moisture representing conditions in extremely different areas, parameterization according to the simple linear Dalton-formula leads to an ‘apparent negative moisture flux’. It is argued that this effect can be traced to deviations of moisture conditions at the interface from the saturation value according to the subsurface sea-temperature. The measurements presented were taken over the German Bight and the Baltic sea using a microwave-refractometer, a sonic-anemometer and a fine platinum wire thermometer. The BOMEX-and San Diego measurements (Phelps and Pond, 1971) have been added to the sample.