TY - JOUR
T1 - An occluded coastal oceanic front
AU - Marmorino, G. O.
AU - Shen, C. Y.
AU - Allan, N.
AU - Askari, F.
AU - Trizna, D. B.
AU - Trump, C. L.
AU - Shay, L. K.
N1 - Funding Information:
This work is a contribution to the High-Resolution Remote Sensing Program, which was supported by the Office of Naval Research and managed at NRL by R. Mied. Support for the OSCR measurements came from ONR and the Coastal Physical Oceanography Program of the U.S. Minerals Management Service. L. K. Shay was supported by ONR and MMS under contracts N00014-91-J-4133 and N00014-96-I-0111. D. Ross was instrumental in the acquisition of the OSCR data. T. Donato made Figure 2 and G. Lindemann helped make Figures 4 and 11. T. Evans ran the simulations and produced Figures 12-14. The numerical simulation was supported in part by a grant of computer time from the DoD HPC Shared Resource Center, CEWES, Cray C-90. Comments from two anonymous reviewers were helpful in revising the manuscript. This paper is dedicated to the master and crew of the USNS Bartlett (now the Abou Al Barbari), which made her final scientific voyage in June 1993 in support of the High-Res field program.
PY - 1998/9/15
Y1 - 1998/9/15
N2 - Field observations, including hydrographic, microwave imaging radar, and HF radar measurements, reveal the evolution of a complicated frontal interaction between three water masses on the continental shelf near Cape Hatteras, North Carolina, during a period of incursion of water from the Gulf Stream. The water masses were found to be separated by intersecting frontal lines configured in a manner analogous to an occluded atmospheric front. The densest water lay between inshore and offshore fronts that gradually merged or occluded in the generally downstream direction, leaving a single surface front. The overall frontal structure appeared as a distinct Y-shaped feature in the radar imagery, similar to historical imagery of the study area. The interpretation of the observations is aided by the use of a two-dimensional numerical model. The model is initialized with two fronts idealized from the ocean measurements. The model fronts quickly sharpen and begin to move together, eventually occluding into a single surface front. As a result of the occlusion, the water mass having intermediate density subducts and intrudes under the most buoyant water, carrying with it strong horizontal and vertical shears, and a frontal band of diverging currents is created in the densest water mass. The model thus suggests that in the ocean there will be an increase in hydrographic and velocity fine structure downstream of the frontal occlusion point.
AB - Field observations, including hydrographic, microwave imaging radar, and HF radar measurements, reveal the evolution of a complicated frontal interaction between three water masses on the continental shelf near Cape Hatteras, North Carolina, during a period of incursion of water from the Gulf Stream. The water masses were found to be separated by intersecting frontal lines configured in a manner analogous to an occluded atmospheric front. The densest water lay between inshore and offshore fronts that gradually merged or occluded in the generally downstream direction, leaving a single surface front. The overall frontal structure appeared as a distinct Y-shaped feature in the radar imagery, similar to historical imagery of the study area. The interpretation of the observations is aided by the use of a two-dimensional numerical model. The model is initialized with two fronts idealized from the ocean measurements. The model fronts quickly sharpen and begin to move together, eventually occluding into a single surface front. As a result of the occlusion, the water mass having intermediate density subducts and intrudes under the most buoyant water, carrying with it strong horizontal and vertical shears, and a frontal band of diverging currents is created in the densest water mass. The model thus suggests that in the ocean there will be an increase in hydrographic and velocity fine structure downstream of the frontal occlusion point.
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U2 - 10.1029/98JC02099
DO - 10.1029/98JC02099
M3 - Article
AN - SCOPUS:0032531390
VL - 103
SP - 21587
EP - 21600
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
SN - 2169-897X
IS - C10
ER -