
Subsurface, surface, and radar modeling of a Gulf Stream current convergence
Author(s) -
Jansen Robert W.,
Shen Colin Y.,
Chubb Scott R.,
Cooper Arnold L.,
Evans T. E.
Publication year - 1998
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/98jc01195
Subject(s) - geology , radar , current (fluid) , gulf stream , backscatter (email) , geophysics , remote sensing , mechanics , physics , oceanography , telecommunications , computer science , wireless
In this paper we investigate the underlying dynamics associated with a strong, line‐shaped submesoscale feature that was observed in radar imagery at the boundary between Gulf Stream (GS) and shelf water near Cape Hatteras during the first Naval Research Laboratory High‐Resolution Remote Sensing Experiment (HIRES 1). The line‐shaped feature, which appears as a pronounced (∼10 dB) increase in radar cross section, extends several kilometers in the east‐west direction. In situ current measurements have shown that this feature coincides with the boundary of a sharp current convergence front. These measurements also indicate that the frontal dynamics is associated with the subduction of denser GS water under lighter shelf water. Using the observation that the convergence can be attributed to a hydrodynamic instability at the water interface, we have modeled the resulting subsurface hydrodynamics on the basis of a rigid‐lid, two‐dimensional solution of the Navier Stokes equation. The calculations of subsurface current flow were used as input to a spectral (wave action) model of wave‐current interaction to obtain the surface wave field, which in turn was used to provide input for modeling of radar backscatter. The resulting description also includes the effects of surfactant‐induced wave damping on electromagnetic backscatter. Our predictions are compared with real aperture radar imagery and in situ measurements from the HIRES 1 experiment.