A Numerical Study of Loop Current Intrusions and Eddy Shedding

Abstract The dynamics of the eddy shedding by the Loop Current in the Gulf of Mexico have been investigated using three nonlinear numerical models: two-layer, barotropic and reduced gravity. The barotropic and reduced gravity models demonstrate the individual behavior of the external and internal modes, and provide insight into how they interact in the two-layer model. Because of the economy of the semi-implicit free surface models, it was possible to perform over 100 experiments to investigate the stability properties of the Loop Current. Typically, the models were integrated 3–5 years to statistical equilibrium on a 1600 km×900 km rectangular domain with a resolution of 20 km×18.75 km. Prescribed inflow through the model Yucatan Channel was compensated by outflow through the Florida Straits. A long-standing hypothesis is that the Loop Current sheds eddies in response to quasi-annual variations in the inflow. We find that the Loop Current can penetrate into the Gulf, bend westward, and shed realistic ant...

[1]  R. V. Madala.  An Efficient Direct Solver for Separable and Non-Separable Elliptic Equations , 1978 .

[2]  A. Arakawa,et al.  Numerical methods used in atmospheric models , 1976 .

[3]  J. O'Brien,et al.  A Numerical Model of Coastal Upwelling , 1972 .

[4]  R. Hockney.  Formation and Stability of Virtual Electrodes in a Cylinder , 1968 .

[5]  A. Grammeltvedt.  A SURVEY OF FINITE-DIFFERENCE SCHEMES FOR THE PRIMITIVE EQUATIONS FOR A BAROTROPIC FLUID , 1969 .

[6]  H. Hurlburt,et al.  Coastal Upwelling on a β-Plane , 1973 .

[7]  S. Philander.  Instabilities of zonal equatorial currents, 2 , 1976 .

[8]  J. McWilliams,et al.  On the evolution of isolated, nonlinear vortices , 1979 .

[9]  W. Sturges,et al.  A Western Boundary Current in the Gulf of Mexico , 1976, Science.

[10]  Roger W. Hockney,et al.  A Fast Direct Solution of Poisson's Equation Using Fourier Analysis , 1965, JACM.

[11]  J. Reid,et al.  Winter Circulation Patterns and Property Distributions , 1972 .

[12]  Douglas K. Lilly,et al.  ON THE COMPUTATIONAL STABILITY OF NUMERICAL SOLUTIONS OF TIME-DEPENDENT NON-LINEAR GEOPHYSICAL FLUID DYNAMICS PROBLEMS , 1965 .

[13]  D. Hansen,et al.  Deep currents in the Yucatan Strait , 1979 .

[14]  R. Hockney.  The potential calculation and some applications , 1970 .

[15]  William R. Holland,et al.  Baroclinic and topographic influences on the transport in western boundary currents , 1973 .

[16]  William R. Holland,et al.  On the Generation of Mesoscale Eddies and their Contribution to the OceanicGeneral Circulation. I. A Preliminary Numerical Experiment , 1975 .

[17]  D. Leipper.  A sequence of current patterns in the Gulf of Mexico , 1970 .

[18]  W. R. Holland,et al.  On the Generation of Mesoscale Eddies and their Contribution to the OceanicGeneral Circulation. II. A Parameter Study , 1975 .

[19]  André Robert,et al.  A SEMI-IMPLICIT SCHEME FOR GRID POINT ATMOSPHERIC MODELS OF THE PRIMITIVE EQUATIONS , 1971 .

[20]  J. E. Case,et al.  Geophysical Studies in the Gulf of Mexico , 1975 .

[21]  Robert L. Molinari,et al.  The variability of anticyclonic current patterns in the Gulf of Mexico , 1977 .