Time scales and structure of topographic Rossby waves and meanders in the deep Gulf Stream

Author: Johns W. E.   Watts D. R.  

Publisher: Sears Foundation for Marine Research

ISSN: 1543-9542

Source: Journal of Marine Research, Vol.44, Iss.2, 1986-05, pp. : 267-290

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Abstract

During July–November 1982, current and temperature records were collected from six current meters spanning the lower 2000 m of the water column on two moorings in the Gulf Stream northeast of Cape Hatteras, N.C. Frequency domain EOF analysis of the velocity cross-spectra reveals that there are two kinematically distinct wave processes present in the subinertial range, identifiable as topographic Rossby wave and meander-associated motions, which are energetically dominant at periods longer than and shorter than 14 days, respectively.Simultaneous thermocline depth measurements obtained using inverted echo sounders show that the low-frequency topographic Rossby wave motions are uncoupled with near-surface displacements of the Gulf Stream path, but that cross-stream velocity fluctuations in the 14-day and 5-day period bands are associated with vertically coherent meanders of the Gulf Stream temperature front.