The Role of the Southern Ocean/Sea Ice Interaction in Global Climate Change,
LAMONT-DOHERTY GEOLOGICAL OBSERVATORY PALISADES NY
Pagination or Media Count:
The seasonal sea ice field of the Southern Ocean strongly modulates climate through its insulating effect and high albedo. Consequently, it plays a significant role in global climate and must be adequately parameterized for inclusion in large-scale circulation models attempting to predict the nature of global change. Recent field studies and modeling work show that the ice field is highly sensitive to the static stability and vertical fluxes in the Southern Ocean water column. Given the marginal stability and strong fluxes of the present-day water column, relatively small changes in the oceanatmosphere may lead to significant changes in the stability or fluxes and thus the nature of the sea ice cover. These interactions link the local- and regional-scale processes to the global-scale processes, forming a Southern Oceanclimate feedback loop. The local-scale processes operate at sub-grid scales in most climate models therefore the results of a local process-oriented model are reviewed to examine the nature of the local-regional interactions which are critical to this system. The model scalings, which describe the system parameter dependence, indicate the direction and magnitude of change of the key external parameters which will drive the system toward a more stable or more unstable state. They also allow a computationally efficient means of monitoring the key elements of the oceansea ice system in large-scale models. The main external parameters include 1 depth of the pycnocline 2 ratio of heat to salt through the pycnocline 3 strength of the pycnocline and 4 magnitude of atmospheric cooling. The divergence of the ice field also plays an important role.
- Snow, Ice and Permafrost
- Physical and Dynamic Oceanography