Mixing and vertical heat flux estimates in the Arctic Eurasian Basin

This paper presents results of an analysis into the magnitude and distribut ion of vertical heat flux from the warm Atlantic Water core into the upper ocean over the southern Eurasian Basin of the Arctic Ocean as determined by Acoustic Doppler Current Profiles (ADCP) and Conductivity, Temperature, an d Depth (CTD) casts made in 1993 and 1995. Vertical diffusivity parameteriz ations based on shear and buoyancy frequency squared are utilized, includin g one that assumes that turbulent dissipation rates associated with interna l wave variance dissipation can be estimated from vertical shear and buoyan cy frequency profiles [Gregg, M.C., 1989. Scaling turbulent diffusion in th e thermocline. J. Geophys. Res., 94, pp. 9686-9698; D'Asaro, E.A., Morison, J.H., 1992. Internal waves and mixing in the Arctic Ocean. Deep-Sea Res., 39 (Suppl. 2), pp. S459-S484], and another based on an inverse Richardson n umber parameterization [Pacanowsky, R.C., Philander, S.G.H., 1981. Paramete rization of vertical mixing in numerical models of tropical oceans. J. Phys . Oceanogr., 11, pp. 1443-1451]. Due to the scarcity of measurements in the Arctic, these data provide a preliminary indication as to the magnitude an d spatial distribution of vertical heat flux from the warm core, below the halocline, into the upper ocean. The data suggest that vertical heat flux p eaks over the continental slope region of the Eurasian Basin. It is possibl e that this diffusion is associated with elevated tidal forcing over the sh elf break and slope regions, although our ship board ADCP records are too s hort to resolve tidal currents directly. (C) 1999 Published by Elsevier Sci ence B.V.