The Deep Waters in the Laurentian Channel

Abstract

Data pertinent to the deep warm waters of a three-layer system in the Cabot Strait area of the Laurentian Channel have been collected since 1915. Typical temperature–depth curves indicate that the temperature of the deep layer reaches a maximum at about 250 m. which shows little or no seasonal variations. Observations show warming of the deep layer from the 1920's to the 1950's. This upward trend of temperatures is accompanied by an increase in volume of the deep layer. The deep layer consists of a mixture of "Labrador" and "Slope" waters in which the mixing ratio of the components remains fairly constant from year to year. Fluctuations in temperature of "Labrador" water are reflected by a corresponding change in temperature of the deep layer in the Laurentian Channel. The vertical structure of the waters in the lower Laurentian Channel and the transport of the waters in Cabot Strait suggest that in the deep layers, there is a continuing supply of oceanic waters to the Gulf of St. Lawrence.