Accurate and Robust Quantification of Energy Pathways in the Ocean

Abstract:

The oceans display energetic dynamics across a wide range of spatial scales, and researchers have long worked to better understand the energy coupling between these various scales. While quantification of such scale-transfer has been previously attempted as part of this effort to understand energy pathways, assumptions of homogeneity and isotropy have presented a limitation upon the applicability of the analyses.

Here we present a more general technique to the quantification of energy transfer between scales, unrestricted by the usual assumptions of homogeneity or isotropy, which allows one to simultaneously probe the dynamics in both space and time. The technique we apply makes use of a novel coarse-graining framework to directly analyze the coupling between scales. We apply this technique, with care to consider the spherical geometry of the problem, in order to study the energy pathways from strongly eddying simulations using LANL’s Parallel Ocean Program (POP). We examine the extent to which the traditional paradigm for such pathways is valid at various locations such as in western boundary currents, near the equator, and in the deep ocean. We investigate the contribution of various nonlinear mechanisms to the transfer of energy across scales such as baroclinic and barotropic instabilities.