Mixing and convection in the Greenland Sea from a tracer-release experiment

摘要: Convective vertical mixing in restricted areas of the subpolar oceans, such as Greenland Sea, is thought to be process responsible for forming much dense water ocean interior1,2. Deep-water formation varies substantially on annual and decadal timescales3,4,5, responds regional climate signals North Atlantic Oscillation6,7; its variations may therefore give early warning changes thermohaline circulation that accompany change8. Here we report direct measurements mixing, by convection turbulence, from a sulphur hexafluoride tracer-release experiment central Sea gyre. In summer, found rapid turbulent about 1.1 cm2 s-1. following late winter, part column was mixed more vigorously convection, indicated rising redistribution tracer patch centre At same time, outside gyre only slightly greater than summer. The results suggest 10% vertically transported convective plumes, which reached surface to, at their deepest, 1,200–1,400 m. Convection limited very area, however, smaller volumes were depth previously estimated9. Our imply it year-round rather dominates region whole.