The Transient Response of the Southern Ocean Pycnocline to Changing Atmospheric Winds
Abstract
The density structure of the Southern Ocean (SO) is dynamically linked to wind stress at the surface, but the nature of this coupling is not fully understood. Observations from the last several decades show a significant increase in the strength of eastward winds over the SO, but an appreciable change in the tilt of density surfaces has not yet been detected there. To investigate the mechanisms that control the response of the SO pycnocline to an increase in wind stress, we developed a hierarchy of models, including a highly idealized analytical model and a numerical sector model. The idealized analytical model suggests that coupling between the SO and northern basins dictates the response of the vertical density structure on multi-decadal to centennial timescales. Our numerical simulations also show that the adjustment process of the SO pycnocline occurs on such timescales. Due to this long response time, it may be difficult to detect significant changes in the tilt of isopycnals in the circumpolar current with a few decades of hydrographic observation. Our results provide a new interpretation for recent observations and highlight the importance of the interaction between regional SO dynamics and global ocean circulation.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMOS53B1384J
- Keywords:
-
- 4207 OCEANOGRAPHY: GENERAL / Arctic and Antarctic oceanography;
- 4215 OCEANOGRAPHY: GENERAL / Climate and interannual variability;
- 4500 OCEANOGRAPHY: PHYSICAL;
- 4513 OCEANOGRAPHY: PHYSICAL / Decadal ocean variability