Lagrangian connections and circulation in the western Scotian Shelf

J. A. Shore, C. G. Hannah, and J. W. Loder

A quantitative representation of 3-d seasonal and M2 tidal circulation in the Scotia-Maine region has recently been developed from diagnostic and prognostic finite element models forced by observational data.

Seasonal mean variations in circulation and hydrography of the major shelf-scale processes on the western Scotian Shelf are presented. Spatial variations in tidal regimes, complex bathymetry and the conflux of different water masses lead to strong contrasts in hydrographic regimes.

Particle tracking in the 3-d seasonal-mean and tidal current fields is used to develop a Lagrangian view of circulation in the Scotian Shelf-Gulf of Maine region which is more appropriate to biological and other drift issues in such spatially- and temporally- varying flow fields. Resulting pathways are used to present Lagrangian connections between the southwest Nova Scotia region and Georges Bank and to explore implications for biota in selected areas of the western Scotian Shelf.

The results indicate significant influences of seasonality, vertical structure, tidal currents and other flow perturbations on drift pathways in the Scotia-Maine region.