Vertical Circulation Revealed by Diurnal Heating of the Upper Ocean in Late Winter: Part I: Observations

Abstract

Inst. Oceanogr. Sci., Deacon Lab., Brook Rd., Wormley, Godalming, Surrey GU8 5UB, UK J (Journal-Article) M (Marine) During a 5-day period in late winter 1984, temperatures were measured at 9 depths beneath a drifting spar buoy to a relative accuracy of 2 mK. The depths ranged from 15 to 145 m in a mixing layer that was nearly homogeneous to over 250 m. A diurnal temperature signal was observed, whose maximum amplitude decreased from 40 mK at 15 m to 20 mK at 145 m. Surface heat fluxes, in particular the diurnal variation in solar radiation, are too small to account for the diurnal variations in mixed layer heat content. It is concluded that the spar was trapped in a convergence zone, where vertical velocities possibly as large as 0.04 m/s carried diurnally heated surface water down to 145 m within hours ASFA 2: Ocean Technology, Policy and Non Living Resources (Q2) 2175866 -------------------------------------------------------------...