Multi-Year Observations of Deep Water Renewal in Foxe Basin, Canada

New oceanographic mooring data recorded between 2004 and 2006 show an abrupt arrival of cold and saline water at the bottom of Foxe Channel each year. Foxe Channel is the deepest part of Foxe Basin, an Arctic/Subarctic inland sea in the Hudson Bay system. This dense water mass is detected at depth in the middle of the channel at the beginning of spring. It is characterized by a sharp temperature drop and salinity rise. This pulse-like phenomenon is recurrent, although there is some interannual variability depending on the severity of the preceding winter. the dense water probably orignates from the coastal polynyas of western Foxe Basin. A gravity current in Foxe Channel flows southeastwards and significantly modifies the water column along the channel by raising isotherms by 140 m. The water column responds to the dense water pulse with a time lag of one month. Although the pulse lasts only three months, it renews more than two-thirds of the deep water in Foxe pulse is an energetic event and that the newly advected dense water may have enough kinetic energy of overflow the sill between Foxe Basin and Hudson Bay.