Vertical structure of eddies and related vertical eddy heat and carbon transport.

Sjoerd Groeskamp, Royal Netherlands Institute for Sea Research, Den Burg, Netherlands, Joseph Henry LaCasce, University of Oslo, Department of Geosciences, Oslo, Norway and Trevor J McDougall, University of New South Wales, Sydney, NSW, Australia
Abstract:
Eddies stir and mix heat, carbon and other tracers throughout the ocean. Eddy flux parametrizations are mostly implemented as an eddy diffusivity operating on a tracer gradient. An accurate representation of eddy fluxes is therefore complicated, as it requires knowledge of 1) the spatial and temporal structure of eddy diffusivities, and 2) accurate numerical representation of tracer gradients rotated along the neutral direction. Here we present recent advances made on both these aspects.

Mostly from existing observations of temperature and salinity alone, we provide new estimates of the vertical structure of eddy diffusivities. We also show results of a new algorithm (VENM) that provided a much-improved numerical representation of the required neutral gradients upon which eddy diffusivities operate. Considering the significant impact of these advances on observational-based estimates of vertical ocean heat and carbon transport, fictitious diffusion and overturning circulation, we expect future calculation in models and observations to adopt aspects of the presented methods.