Eddy trains and striations in quasigeostrophic simulations and the ocean

This study explores the relationship between coherent eddies and zonally elongated striations. The investigation involves an analysis of two baroclinic quasigeostrophic models of a zonal and double-gyre flow and a set of altimetry sea level anomaly data in the North Pacific. Striations are defined b...

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Bibliographic Details
Published in:Journal of Physical Oceanography
Main Authors: Chen, C, Kamenkovich, I, Berloff, P
Other Authors: Natural Environment Research Council (NERC)
Format: Article in Journal/Newspaper
Language:English
Published: American Meteorological Society 2016
Subjects:
Online Access:http://hdl.handle.net/10044/1/43792
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000384024900013&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
https://doi.org/10.1175/JPO-D-16-0066.1
Description
Summary:This study explores the relationship between coherent eddies and zonally elongated striations. The investigation involves an analysis of two baroclinic quasigeostrophic models of a zonal and double-gyre flow and a set of altimetry sea level anomaly data in the North Pacific. Striations are defined by either spatiotemporal filtering or empirical orthogonal functions (EOFs), with both approaches leading to consistent results. Coherent eddies, identified here by the modified Okubo???Weiss parameter, tend to propagate along well-defined paths, thus forming ???eddy trains??? that coincide with striations. The striations and eddy trains tend to drift away from the intergyre boundary at the same speed in both the model and observations. The EOF analysis further confirms that these striations in model simulations and altimetry are not an artifact of temporal averaging of random, spatially uncorrelated vortices. This study suggests instead that eddies organize into eddy trains, which manifest themselves as striations in low-pass filtered data and EOF modes.