Shelf dense water transport in the Beaufort Sea

CTD data from the Beaufort Sea showed fresh surface water of 27 psu in August compared to 31 psu in April, which indicates a saline injection during the winter freezing season. Where and how those cold and salty dense water moves is very important to the halocline formation process. A coupled ice-ocean model is used to simulate the circulation and ice dynamics and thermodynamics in the Beaufort Sea. With 3.4km horizontal resolution and 16 vertical layers, this nested model obtains open boundary conditions from a similar model with large domain including Arctic and North Atlantic Oceans with 27.5km horizontal resolution. Numerical tracer studies revealed that the rate of dense shelf water penetrating the slope halocline in the Beaufort Sea is low which agrees with results from observations. Sensitivity studies with idealized model identified that salinity stratification is the main reason for the low rate. Wind is important for the position and shape of the horizontal front over the shelf break. Wind and geostrophic flow generated by horizontal salinity front over the shelf break are the two sources of shelf break transports, and among which, wind is the dominant factor. Eddy activities over shelf break generated by salinity front are evident while the shelf break flow along the same direction as the geostrophic flow generated by the front, but in case of reversal of this flow by wind, the eddy activities are also depressed.