Abstract
In this paper the spectrum of barotropic basin modes of the Argentine Basin is shown to be connected
to the classical Rossby basin modes of a flat-bottom (constant depth), rectangular basin. First, the spectrum
of basin modes is calculated for the Argentine Basin, by performing a normal-mode analysis of the barotropic
shallow-water equations. Then a homotopy transformation is performed that gradually morphs the
full-bathymetry geometry through a flat-bottom configuration into a rectangular basin. Following the
eigenmodes through this transition establishes a connection between most of the basin modes and the
classical Rossby basin modes of a rectangular geometry. In particular, the 20-day mode of the Argentine
Basin is identified with the lowest-order mode of classical theory. Sensitivity studies show that the decay
rate of each mode is controlled by bottom friction, but that it is insensitive to lateral friction; lateral friction
strongly impacts the oscillation frequency. In addition, the modes are found to be only slightly sensitive to
the presence of a background flow.
| Original language | Undefined/Unknown |
|---|---|
| Pages (from-to) | 2869-2881 |
| Number of pages | 13 |
| Journal | Journal of Physical Oceanography |
| Volume | 37 |
| Issue number | 12 |
| Publication status | Published - 2007 |