Measurements of the oceanic thermal skin effect

Spectroradiometric measurements of the ocean skin temperature and thermometric measurements of the bulk temperature at a depth of about 5 cm taken from the R/V Tangaroa during SAGE (SOLAS/SAGE: surface-ocean lower-atmosphere studies air–sea gas exchange experiment) off New Zealand are analyzed to reveal the wind speed dependence of the temperature difference across the thermal skin layer (ΔT). The wind speeds used here are corrected for flow distortion by the ship. Unlike most previously published measurements of ΔT, these data include those taken during the day, prior analyses being usually restricted to night-time measurements to avoid contamination of the data by diurnal heating. The results show the same dependence of ΔT on wind speed at night-time measurements, with an asymptotic behavior at a value of −0.13 K at high winds. These data show larger ΔT at low wind speeds than previous studies, and there is an indication that this may reveal a dependence on sea surface temperature.