Constraining an eddy energy dissipation rate due to relative wind stress for use in energy budget-based eddy parameterisations

Wilder, Thomas, Zhai, Xiaoming, Munday, David R. and Joshi, Manoj ORCID: https://orcid.org/0000-0002-2948-2811 (2023) Constraining an eddy energy dissipation rate due to relative wind stress for use in energy budget-based eddy parameterisations. Ocean Science, 19 (6). 1669–1686. ISSN 1812-0784

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Abstract

A geostrophic eddy energy dissipation rate due to the interaction of the large-scale wind field and mesoscale ocean currents, or relative wind stress, is derived here for use in eddy energy budget-based eddy parameterisations. We begin this work by analytically deriving a relative wind stress damping term and a baroclinic geostrophic eddy energy equation. The time evolution of this analytical eddy energy in response to relative wind stress damping is compared directly with a baroclinic eddy in a general circulation model for both anticyclones and cyclones. The dissipation of eddy energy is comparable between each model and eddy type, although the numerical model diverges from the analytical model at around day 150, likely due to the presence of non-linear baroclinic processes. A constrained dissipation rate due to relative wind stress is then proposed using terms from the analytical eddy energy budget. This dissipation rate depends on the potential energy of the eddy thermocline displacement, which also depends on eddy length scale. Using an array of ocean datasets, and computing two forms for the eddy length scale, a range of values for the dissipation rate are presented. The analytical dissipation rate is found to vary from 0.25 to 4 times that of a constant dissipation rate employed in previous studies. The dissipation rates are generally enhanced in the Southern Ocean but smaller in the western boundaries. This proposed dissipation rate offers a tool to parameterise the damping of total eddy energy in coarse resolution global climate models and may have implications for a wide range of climate processes.

Item Type:	Article
Additional Information:	Financial support: This work was funded by the Natural Environment Research Council through the EnvEast Doctoral Training Partnership (grant no. NE/L002582/1) and the European Union's Horizon 2020 research and innovation programme under grant agreement no. 101003536 (ESM2025 – Earth System Models for the Future).
Faculty \ School:	Faculty of Science > School of Environmental Sciences Faculty of Science > School of Natural Sciences University of East Anglia Research Groups/Centres > Theme - ClimateUEA
UEA Research Groups:	Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences Faculty of Science > Research Groups > Climatic Research Unit University of East Anglia Schools > Faculty of Science > Tyndall Centre for Climate Change Research Faculty of Science > Research Centres > Tyndall Centre for Climate Change Research
Depositing User:	LivePure Connector
Date Deposited:	22 Oct 2023 01:10
Last Modified:	04 Mar 2024 18:21
URI:	https://ueaeprints.uea.ac.uk/id/eprint/93402
DOI:	10.5194/os-19-1669-2023

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