Multi-decadal trends in the advection and mixing of carbon in the Southern Ocean


The intermediate and deep waters of the ocean store nearly 40,000 petagrams of carbon, more than 60 times that of the atmosphere. In the Southern Ocean, ventilation along isopycnals connects carbon-rich deep water to the surface, permitting carbon dioxide (CO2) stored in the deep ocean to escape to the atmosphere. As such, the Southern Ocean is a significant source of CO2 for the atmosphere.

Observations over the last 50 years indicate that the westerly winds over the Southern Ocean have strengthened, due to anthropogenic-induced changes in the climate system. Here, I assess the impact of this multi-decadal increase in wind intensity on the advection, mixing, and air-sea exchange of carbon in the Southern Ocean using a coarse-resolution ocean model with a variable eddy-induced advection coefficient. The model predicts an increase in the sea-air flux of CO2, caused by wind-driven increases in the advection and diapycnal mixing of carbon into the surface ocean. The trend toward enhanced outgassing is countered by a simultaneous increase in the eddy-induced advection of carbon, which opposes the Eulerian flow.

Sep 17, 2013 3:30 PM — 4:30 PM
Bechtel Collaboratory, Discovery Learning Center
Engineering Center, University of Colorado at Boulder, Boulder, CO 80309

INSTAAR/ATOC, University of Colorado Boulder