Labrador sea freshwater content in a model with a partial cell topographic representation

Two experiments are run with an eddy-permitting model of the sub-polar North Atlantic, using full and partial cell formulations of the underlying bottom topography. Although there are numerous improvements in the circulation in the partial cell experiment, there is also a serious degrading of the hydrography, through an unexpected and unrealistic increase in the salinity within the Labrador Sea. An analysis of the freshwater and heat budgets of the Labrador Sea in the model experiments show significant changes in the partial cell experiment, with respect to the full cell experiment, associated with a net flux of freshwater out of the Labrador Sea. The main components of this increased flux is the greater import of high salinity water from the North Atlantic current and the enhanced export of Labrador Sea Water directly to the Irminger Sea. Both of these fluxes are primarily related to the presence of a strong Labrador Sea counter-current in the partial cell simulation. One striking feature associated with the generation of the counter-current is a very large amount of eddy activity along the Labrador slope. A brief energy analysis, including examining the time-rates of conversion between the different types of energies, is given for both experiments. This analysis suggests that the increased production of eddies in the partial cell experiment is at least partly due to enhanced baroclinic instability occurring in frontal regions. Additionally, a net conversion of eddy kinetic energy into mean kinetic energy that only occurs in the partial cell experiment suggests that the Labrador Sea counter-current is in part driven by these eddies.