The spatial structure of subinertial current fluctuations in a section across western Long Island Sound is investigated by using the method of empirical orthogonal functions. The variability in the deeper areas of the section is found to be dominated by a setup response to the longitudinal wind. Toward the southern side of the basin, much of the variance cannot be explained by this mechanism. Spectral analysis indicates that the currents in this area have increased short period variance, with periods between 40 and 55 hours, and tend to be highly polarized. A model of topographic waves in an infinite channel with a symmetric exponential bottom profile is shown to predict the polarization and cross-channel structure of velocity fluctuations in this band. High rotary coherence between counter-rotating current and wind components in this band, where the group velocity of the wave is nearly zero, suggests the possibility of a resonant response to wind forcing. |