Simulation of Circulation and Ice over the Newfoundland and Labrador Shelves: The Mean and Seasonal Cycle

Abstract

A three dimensional ice–ocean coupled model with a 7 km horizontal resolution has been developed to examine spatial and seasonal variability of hydrography and circulation over the Newfoundland and Labrador Shelves. Daily atmospheric forcing is applied and monthly open boundary forcing is prescribed based on a global ocean assimilation model. Monthly mean results averaged over a simulation period from 1979 to 2010 are evaluated using a variety of temperature, salinity, current, and ice observations. In comparison with observations and previous model results, the present model shows good skill in simulating the inshore and shelf-edge Labrador Current. The model temperature and salinity agree well with observations. Model sea-ice extent compares well with observations. The model mean transport is approximately 7.5 and 0.7 Sv (Sv = 106 m3 s−1) for the shelf-edge and inshore branches of the Labrador Current, respectively, consistent with observational estimates. The modelled total transport from the coast to the central Labrador Sea is 27.5 Sv from June to September, in good agreement with the observational estimate. The seasonal range for the shelf-edge and inshore branches is 2.0 and 0.6 Sv, respectively, strong in winter and fall and weak in spring and summer. The model mean freshwater transport at the Seal Island and Flemish Cap transects is 0.12 and 0.14 Sv, respectively, consistent with observational estimates, and the range of the seasonal freshwater transport is 0.09 Sv and 0.04 Sv for each transect, respectively, which is approximately in phase with the volume transport.