A Simple Model For Cross-Shelf Mixing on the Scotian Shelf

Abstract

The longshore gradients of temperature, salinity, and nitrate concentration along the Scotian Shelf, and their fluxes at a fixed mooring south of Halifax, have been measured separately. Water-mass analysis indicates that the water at the eastern end of the shelf is diluted with slope water by 40% at Halifax as a result of cross-shelf mixing. Recent estimates of the annual mean transport along the shelf are used to infer the longshore gradients supported by the shelf-break fluxes in the context of a simple box model. The observed longshore gradients of temperature, salinity, and nitrate concentration are consistent with productivity requirements and measured low-frequency eddy fluxes at the edge of the Scotian Shelf. Key words: low-frequency eddy fluxes, nutrient enrichment, longshore gradients, cross-shelf mixing, Scotian Shelf