EGU22-7582
https://doi.org/10.5194/egusphere-egu22-7582
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Energy exchanges between two-dimensional front and internal waves.

Subhajit Kar and Roy Barkan
Subhajit Kar and Roy Barkan
  • TelAviv University, Department of Geophysics, TelAviv Yafo, Israel (subhajitkar19@gmail.com)

Fronts and near-inertial waves (NIWs) are energetic motions in the upper ocean that are thought to interact and provide a possible route for kinetic energy dissipation of mesoscale balanced flows. To date, the theoretical explanations for such interactions rely on the fronts being geostrophic, with a weak ageostrophic secondary circulation (ASC) and a small Rossby number. We develop a quasilinear model to study the interactions between NIW vertical modes and a 2D front undergoing semigeostrophic frontogenesis. In our model, frontal sharpening is divided into two stages: an exponential stage, that is characterized by a low Rossby number and is driven by geostrophic strain; and a super-exponential stage, that is characterized by an O(1) Rossby number and is driven by the convergence of the ASC. We identify a new mechanism, the convergence production, through which NIWs can efficiently extract energy from the front during the super-exponential stage. It is shown that the convergence production can dominate the known mechanism of energy extraction during the exponential stage, the deformation shear production, for a relatively strong geostrophic strain field.

How to cite: Kar, S. and Barkan, R.: Energy exchanges between two-dimensional front and internal waves., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7582, https://doi.org/10.5194/egusphere-egu22-7582, 2022.