Kh. Su et al., THE ORIGIN OF LOW-FREQUENCY OSCILLATIONS IN THE SOUTHERN MID-ATLANTICBIGHT, Journal of physical oceanography, 24(6), 1994, pp. 1110-1119
Distinct offshore and upward phase propagation at periods of 12 and 24
days was previously observed in the horizontal flow field on the oute
r shelf in the southern Mid-Atlantic Bight during the Shelf Edge Excha
nge Processes Experiment in spring 1988. A linear, forced-wave model i
s invoked to explain the observed phase propagation. It is found that
the observed phase propagation can exist when currents are in resonanc
e with a vorticity source on the continental slope. It is essential th
at the thermohaline field be characterized by an upper-ocean stratific
ation on the slope for resonance to occur. The phase difference near r
esonance is weakly dependent on the bottom frictional parameter and th
e alongshore length scale of forcing. Resonance is due to onshore prop
agation of topographic waves. It is suggested that low-frequency oscil
lations on the outer shelf in the Mid-Atlantic Bight in winter are ass
ociated with sources on the upper slope.