Remember Me
Or use your Academic/Social account:


Or use your Academic/Social account:


You have just completed your registration at OpenAire.

Before you can login to the site, you will need to activate your account. An e-mail will be sent to you with the proper instructions.


Please note that this site is currently undergoing Beta testing.
Any new content you create is not guaranteed to be present to the final version of the site upon release.

Thank you for your patience,
OpenAire Dev Team.

Close This Message


Verify Password:
Verify E-mail:
*All Fields Are Required.
Please Verify You Are Human:
fbtwitterlinkedinvimeoflicker grey 14rssslideshare1
Nilsson, Johan; Broström, Göran; Walin, Gösta (2004)
Publisher: Co-Action Publishing
Journal: Tellus A
Languages: English
Types: Article

Classified by OpenAIRE into

arxiv: Physics::Atmospheric and Oceanic Physics
The stability of symmetric thermally dominated thermohaline circulation in a two-hemisphere basin is explored with the aid of a conceptual as well as a numerical model. The conceptual model has two layers, representing the water masses of the thermocline and the deep ocean, respectively. The stability of the symmetric solutions of the model to small symmetric or antisymmetric perturbations are considered. It is found that the symmetric equilibria are considerably more sensitive to antisymmetric than to symmetric perturbations. The reason is that a symmetric flow anomaly by necessity causes a perturbation of the thermocline depth; a state of affairs which provides a negative feedback. The strength of this stabilizing feedback depends on the properties of the vertical mixing in the interior ocean. In contrast, the antisymmetric flow perturbations assume a pole-to-pole overturning pattern with negligible vertical motion at low latitudes; this essentially removes the stabilizing feedback due to thermocline–depth adjustment. As a consequence, the dynamics of antisymmetric perturbations are basically independent of the vertical mixing. It is concluded that the symmetric circulation is always unstable to antisymmetric perturbations if ΔρS/ ΔρT > 1/2 , where ΔρS and ΔρT are the equator-to-pole density contrasts created by salinity and temperature, respectively. However, if the interhemispheric density gradients in the deep ocean are assumed to strengthen the antisymmetric flow anomaly, the instability should occur for a considerably smaller value of ΔρS/ ΔρT. Numerical simulations are presented that support the theoretical results and furthermore suggest that the density gradients in the deep ocean indeed augment the antisymmetric flow perturbations, thereby acting to destabilize the symmetric branch of thermally dominated circulation.

Share - Bookmark

Cite this article

Collected from