Sensitivity of basinwide meridional overturning to diapycnal diffusion and remote wind forcing in an idealized Atlantic southern Ocean geometry
Recent numerical experiments indicate that the rate of meridional overturning asso-ciated with North Atlantic Deep Water is partially controlled by windstress in the Southern Ocean, where the zonal periodicity of the domain alters the nature of the flow. Here, the solution of the cubic scale relatio...
| Main Authors: | , , , |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
2003
|
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.489.4814 http://www.soes.soton.ac.uk/staff/jym/Papers/KDMS_2001.pdf |
| Summary: | Recent numerical experiments indicate that the rate of meridional overturning asso-ciated with North Atlantic Deep Water is partially controlled by windstress in the Southern Ocean, where the zonal periodicity of the domain alters the nature of the flow. Here, the solution of the cubic scale relationship of Gnanadesikan (1999) yields a simple expression for meridional overturning which is used to clarify the relative strength of the wind-forced com-ponent. We compare the predicted overturning to coarse-resolution numerical experiments with an idealized Atlantic-Ocean/Southern Ocean geometry. The scaling accurately predicts the sensitivity to forcing for experiments with a level model employing isopycnal diffusion of temperature, salinity, and “layer thickness”. A layer model produces similar results, increas-ing our confidence in the numerics of both models. Level model experiments with horizontal diffusivity have similar qualitative behavior but somewhat different sensitivity to forcing. We highlight the difference in meridional overturning induced by changes in windstress or vertical diffusivity. Strengthening the Southern Ocean windstress induces a circulation anomaly in which most of the water is subducted in the Ekman layer of the wind perturba- |
|---|