The Low-Frequency Residual Circulation in Knight Inlet, British Columbia

Abstract

Many aspects Of the low-frequency response of a stratified inlet have not been previously observed because of the lack of simultaneous observations of runoff, wind, currents, and density over the entire body of water. Month-long observations throughout the water column of Knight Inlet, British Columbia, both outside and inside the sill, during the spring (1988) and summer (1989) runoff regimes are presented. These data are detided with harmonic analysis and used to investigate the subdiurnal residual response with respect to the wind, runoff, and deep water renewal. Near the surface, response to alongchannel winds was found to dominate with a coherence squared of greater than 0.8. The coherence was therefore used to directly estimate the wind influence, and dewinded residuals were formed by subtracting these estimates from the detided records. Structures were found in the dewinded residuals that correspond to a near-surface estuarine circulation vertically nested with deep water renewal.