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Geographical distribution and anisotropy of the inverse kinetic energy cascade, and its role in the eddy equilibrium processes
Author(s) -
Wang Shihong,
Liu Zhiliang,
Pang Chongguang
Publication year - 2015
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2014jc010476
Subject(s) - baroclinity , kinetic energy , cascade , geology , energy flux , energy cascade , anisotropy , sea surface height , flux (metallurgy) , physics , geophysics , inverse , gulf stream , northern hemisphere , atmospheric sciences , climatology , sea surface temperature , classical mechanics , geometry , chemistry , mathematics , organic chemistry , chromatography , astronomy , quantum mechanics
The geographic character of the inverse cascade is analyzed based on the spectral kinetic energy flux calculated in the global ocean, using sea surface height (SSH) data from satellites, reanalysis data, and model outputs. It is shown that the strongest inverse cascade occurs mostly in high‐energy eastward‐flowing currents, such as the Antarctic Circumpolar Current (ACC), the Kuroshio Extension, and the Gulf Stream, which matches the global distribution pattern of the eddy kinetic energy (EKE). Hence, the eddy scales predicted by the local linear baroclinic instabilityL b c iand from the altimeter observationL e d d yare mapped out and compared with the energy injection scaleL i n jand the arrest‐start scaleL a r r e s t − s t a r tof the inverse cascade, respectively. Generally,L b c iagrees well withL i n jin the midlatitude and high‐latitude oceans, especially in the Northern Hemisphere.L e d d yfalls within the arrest ranges of the inverse cascade and is quite close toL a r r e s t − s t a r t. Finally, the depth dependence and the anisotropy of the inverse kinetic energy cascade are also diagnosed in the global ocean. We have found that the strength of the inverse cascades decreases with increasing depth, but the global pattern of the strength is nearly invariable. Meanwhile, the variations in depth hardly affect theL i n jandL a r r e s t − s t a r t. After considering the anisotropy in the spectral flux calculation, a possible inertial range for the zonal spectral kinetic energy flux is expected, where the cascade magnitude will keep a nearly constant negative value associated with the oceanic zonal jets.