Water Circulation in Lake Ontario

Abstract

Data from a high resolution array of self-recording current meters in a north-south cross section of Lake Ontario are presented. The measurements cover a 140-day period from 4 November 1982 to 23 March 1983. Nearshore current fluctuations are large and generally coherent with wind variations while currents in deep water tend to flow in the opposite direction and are quite uniform in the vertical. Time-averaged currents show a pronounced maximum of eastward flow along the south shore balanced by westward flow in the central part of the cross section, while the net transport near the northern shore tends to vanish. The total transport in the belt of eastward flow is ten times larger than the hydraulic transport associated with the Niagara-St. Lawrence flow, thus suggesting a recirculation of 90% of the river inflow. Corroboration of the south shore current measurements is provided by satellite-tracked drogues.