Wind-forced upwelling and internal Kelvin wave generation in Mackenzie Canyon, Beaufort Sea

Abstract

Low-frequency current, temperature, and salinity variations over the shelf break in the southeastern Beaufort Sea (Mackenzie Shelf) are examined to determine the response of seasonally ice-free waters to wind forcing and the role of submarine canyons in upwelling events and shelf circulation. Upwelling events were found to be statistically correlated to northeasterly winds, which transport surface waters offshore and draw up water from deeper layers. The response to alongshore wind stress is significantly amplified in Mackenzie Canyon, where isopycnal displacements of over 400 m are observed. Such displacements are then observed to propagate eastward at a phase velocity near 0.6 m s-1. The canyon is thus a site of intense upwelling, while the collapse of displaced isopycnals subsequent to cessation of wind forcing creates a disturbance propagating northeast along shelf as a free internal Kelvin wave.