Colloquium

A coupled ocean-atmosphere laboratory experiment: The Southern Ocean

Dr. Andy Hogg

Australian National University's Resesarch School of Earth Sciences
Thursday, February 18, 2010, 1:45 PM, EMS W343

The Southern Ocean is one of the most critical parts of the climate  
system, but poor observational constraints and the complexity of  
ocean currents in this region means it is poorly understand, and is  
not well-represented in climate models. Here we will show some novel  
new laboratory experiments which are designed to shed light on this  
problem.

We revisit the classic rotating, thermally driven annulus laboratory  
experiment -- with a twist: a two-fluid system which allows us to  
model coupled ocean-atmosphere dynamics. The key aspect is that we  
use two immiscible fluids with differing thermal expansion  
coefficients so that our "atmosphere" layer has larger spatial scales  
and shorter timescales than our "ocean". We use this system to  
identify the relative roles of mechanical and buoyancy forcing on the  
Southern Ocean circulation, and conclude that the role of buoyancy  
forcing may be stronger than previously thought.