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The small-slope approximation to the full three-dimensional diffusion tensor of epineutral diffusion gives exactly the same tracer flux as the commonly used projected nonorthogonal diffusive flux of layered ocean models and of theoretical studies. The epineutral diffusion achieved by this small-slope approximation is not exactly in the direction of the correct epineutral tracer gradient. That is, the use of the small-slope approximation leads to a very small flux of tracer in a direction in which there is no epineutral gradient of tracer. For (the tracer) temperature or salinity, the difference between the correct epineutral gradient and the smallslope approximation to it is proportional to neutral helicity. The authors also make the point that small-scale turbulent mixing processes act to diffuse tracers isotropically (i.e., the same in each spatial direction) and hence it is strictly a misnomer to call this process ‘‘dianeutral diffusion’’ or ‘‘vertical diffusion.’’ This realization also has implications for the diffusion tensor.

Item Type:	Refereed Article
Keywords:	models and modeling, grid systems, isopycnal coordinates, parameterization, subgrid-scale processes
Research Division:	Physical Sciences
Research Group:	Other physical sciences
Research Field:	Other physical sciences not elsewhere classified
Objective Division:	Environmental Management
Objective Group:	Marine systems and management
Objective Field:	Measurement and assessment of marine water quality and condition
UTAS Author:	Groeskamp, S (Mr Sjoerd Groeskamp)
ID Code:	96115
Year Published:	2014
Web of Science® Times Cited:	24
Deposited By:	IMAS Research and Education Centre
Deposited On:	2014-10-20
Last Modified:	2015-04-01
Downloads:	0