Proximity of the Present-Day Thermohaline Circulation to an Instability Threshold
View/ Open
Tziperman_ProximityPresentDay.pdf (364.7Kb)
Access Status
Full text of the requested work is not available in DASH at this time ("restricted access"). For more information on restricted deposits, see our FAQ.Author
Published Version
https://doi.org/10.1175/1520-0485(2000)030<0090:POTPDT>2.0.CO;2Metadata
Show full item recordCitation
Tziperman, Eli. 2000. Proximity of the present-day thermohaline circulation to an instability threshold. Journal of Physical Oceanography 30(1): 90–104.Abstract
The relation between the mean state of the thermohaline circulation (THC) and its stability is examined using a realistic-geometry primitive equation coupled ocean–atmosphere–ice global general circulation model. The main finding is that a thermohaline circulation that is 25% weaker and less dominated by thermal forcing than that of today’s ocean is unstable within this coupled GCM. Unstable initial ocean climates lead in the coupled model to an increase of the THC, to strong oscillations, or to a THC collapse.The existence of an unstable range of weak states of the THC provides a natural explanation for large-amplitude THC variability seen in the paleo record prior to the past 10000 years: A weakening of the THC due to an external forcing (e.g., ice melting and freshening of the North Atlantic) may push it into the unstable regime. Once in this regime, the THC strongly oscillates due to the inherent instability of a weak THC. Hence the strong THC variability in this scenario does not result from switches between two or more quasi-stable steady states.
Citable link to this page
http://nrs.harvard.edu/urn-3:HUL.InstRepos:3425905
Collections
- FAS Scholarly Articles [18292]
Contact administrator regarding this item (to report mistakes or request changes)