Barotropic and Baroclinic Inverse Kinetic Energy Cascade in the Antarctic Circumpolar Current

Stratified geostrophic turbulence theory predicts an inverse energy cascade for the barotropic (BT) mode. Satellite altimetry has revealed a net inverse cascade in the baroclinic (BC) mode. Here the spatial variabilities of BT and BC kinetic energy fluxes in the Antarctic Circumpolar Current (ACC) w...

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Bibliographic Details
Published in:Journal of Physical Oceanography
Main Authors: Li, Hongjie, Xu, Yongsheng
Format: Report
Language:English
Published: AMER METEOROLOGICAL SOC 2021
Subjects:
Baroclinic flows
Barotropic flows
Antarctica
Energy transport
Fluxes
Jets
Oceanography
CALIFORNIA CURRENT SYSTEM
GEOSTROPHIC TURBULENCE
HORIZONTAL RESOLUTION
SUBMESOSCALE TRANSITION
PRIMITIVE EQUATION
MIDOCEAN EDDIES
SOUTHERN-OCEAN
NORTH PACIFIC
FORM STRESS
EDDY
Antarctic
Pacific
Southern Ocean
The Antarctic
Antarc*
Online Access:http://ir.qdio.ac.cn/handle/337002/170966
https://doi.org/10.1175/JPO-D-20-0053.1
Description
Summary:Stratified geostrophic turbulence theory predicts an inverse energy cascade for the barotropic (BT) mode. Satellite altimetry has revealed a net inverse cascade in the baroclinic (BC) mode. Here the spatial variabilities of BT and BC kinetic energy fluxes in the Antarctic Circumpolar Current (ACC) were investigated using ECCO2 data, which synthesize satellite data and in situ measurements with an eddy-permitting general circulation model containing realistic bathymetry and wind forcing. The BT and BC inverse kinetic energy cascades both reveal complex spatial variations that could not be explained fully by classical arguments. For example, the BC injection scales match better with most unstable scales than with the first-mode deformation scales, but the opposite is true for the BT mode. In addition, the BT and BC arrest scales do not follow the Rhines scale well in terms of spatial variation, but show better consistency with their own energy-containing scales. The reverse cascade of the BT and BC modes was found related to their EKE, and better correlation was found between the BT inverse cascade and barotropization. Speculations of the findings were proposed; however, further observations and modeling experiments are needed to test these interpretations. Spectral flux anisotropy exhibits a feature associated with oceanic jets that is consistent with classical expectations. Specifically, the spectral flux along the along-stream direction remains negative at scales up to that of the studied domain (similar to 2000 km), while that in the perpendicular direction becomes positive close to the scale of the width of a typical jet.

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