EGU21-19, updated on 10 Jan 2023
https://doi.org/10.5194/egusphere-egu21-19
EGU General Assembly 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

A synthesis of upper ocean geostrophic kinetic energy spectra from a global submesoscale permitting simulation

Hemant Khatri1, Stephen Griffies1, Takaya Uchida3, Han Wang4, and Dimitris Menemenlis5
Hemant Khatri et al.
  • 1Princeton University, Atmospheric and Oceanic Sciences, Princeton, United States of America (hkhatri@princeton.edu)
  • 3Institut des Géosciences de l'Environnment, Centre National de la Recherche Scientifique, Grenoble, France
  • 4Department of Physics, University of Toronto, Toronto, Canada
  • 5Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA

In the upper ocean, submesoscale turbulence shows seasonal variability and is pronounced in winter. We analyze geostrophic KE spectra in a submesoscale-permitting global ocean model to study the seasonal variability in the upper ocean turbulence. Submesoscale processes peak in winter and, consequently, geostrophic kinetic energy (KE) spectra tend to be relatively shallow in winter (k-2) with steeper spectra in summer (k-3). The roles of frontogenesis processes and mixed-layer instabilities in submesoscale turbulence and their effects on the evolution of KE spectra over an annual cycle are discussed. It is shown that this transition in KE spectral scaling has two phases. In the first phase (late autumn), KE spectra show a presence of two spectral regimes: k-3 scaling in mesoscales (100-300 km) and k-2 scaling in submesoscales (< 50 km), indicating the coexistence of QG, surface-QG, and frontal dynamics. In the second phase (late winter), mixed-layer instabilities convert available potential energy into KE, which cascades upscale leading to flattening of the KE spectra at larger scales, and k-2 power-law develops in mesoscales too.

How to cite: Khatri, H., Griffies, S., Uchida, T., Wang, H., and Menemenlis, D.: A synthesis of upper ocean geostrophic kinetic energy spectra from a global submesoscale permitting simulation, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-19, https://doi.org/10.5194/egusphere-egu21-19, 2021.

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