Proximity of the Present-Day Thermohaline Circulation to an Instability Threshold
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 dominat...
Main Author: | |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
American Meteorological Society
2000
|
Subjects: | |
Online Access: | http://nrs.harvard.edu/urn-3:HUL.InstRepos:3425905 https://doi.org/10.1175/1520-0485(2000)030<0090:POTPDT>2.0.CO;2 |
id |
ftharvardudash:oai:dash.harvard.edu:1/3425905 |
---|---|
record_format |
openpolar |
spelling |
ftharvardudash:oai:dash.harvard.edu:1/3425905 2023-05-15T17:33:10+02:00 Proximity of the Present-Day Thermohaline Circulation to an Instability Threshold Tziperman, Eli 2000 application/pdf http://nrs.harvard.edu/urn-3:HUL.InstRepos:3425905 https://doi.org/10.1175/1520-0485(2000)030<0090:POTPDT>2.0.CO;2 en_US eng American Meteorological Society http://dx.doi.org/10.1175/1520-0485(2000)030<0090:POTPDT>2.0.CO;2 http://www.seas.harvard.edu/climate/eli/reprints/Tziperman-2000a.pdf Journal of Physical Oceanography Tziperman, Eli. 2000. Proximity of the present-day thermohaline circulation to an instability threshold. Journal of Physical Oceanography 30(1): 90–104. 0022-3670 http://nrs.harvard.edu/urn-3:HUL.InstRepos:3425905 doi:10.1175/1520-0485(2000)030<0090:POTPDT>2.0.CO;2 Journal Article 2000 ftharvardudash https://doi.org/10.1175/1520-0485(2000)030<0090:POTPDT>2.0.CO;2 2022-04-04T12:42:11Z 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. Earth and Planetary Sciences Version of Record Article in Journal/Newspaper North Atlantic Harvard University: DASH - Digital Access to Scholarship at Harvard |
institution |
Open Polar |
collection |
Harvard University: DASH - Digital Access to Scholarship at Harvard |
op_collection_id |
ftharvardudash |
language |
English |
description |
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. Earth and Planetary Sciences Version of Record |
format |
Article in Journal/Newspaper |
author |
Tziperman, Eli |
spellingShingle |
Tziperman, Eli Proximity of the Present-Day Thermohaline Circulation to an Instability Threshold |
author_facet |
Tziperman, Eli |
author_sort |
Tziperman, Eli |
title |
Proximity of the Present-Day Thermohaline Circulation to an Instability Threshold |
title_short |
Proximity of the Present-Day Thermohaline Circulation to an Instability Threshold |
title_full |
Proximity of the Present-Day Thermohaline Circulation to an Instability Threshold |
title_fullStr |
Proximity of the Present-Day Thermohaline Circulation to an Instability Threshold |
title_full_unstemmed |
Proximity of the Present-Day Thermohaline Circulation to an Instability Threshold |
title_sort |
proximity of the present-day thermohaline circulation to an instability threshold |
publisher |
American Meteorological Society |
publishDate |
2000 |
url |
http://nrs.harvard.edu/urn-3:HUL.InstRepos:3425905 https://doi.org/10.1175/1520-0485(2000)030<0090:POTPDT>2.0.CO;2 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
http://dx.doi.org/10.1175/1520-0485(2000)030<0090:POTPDT>2.0.CO;2 http://www.seas.harvard.edu/climate/eli/reprints/Tziperman-2000a.pdf Journal of Physical Oceanography Tziperman, Eli. 2000. Proximity of the present-day thermohaline circulation to an instability threshold. Journal of Physical Oceanography 30(1): 90–104. 0022-3670 http://nrs.harvard.edu/urn-3:HUL.InstRepos:3425905 doi:10.1175/1520-0485(2000)030<0090:POTPDT>2.0.CO;2 |
op_doi |
https://doi.org/10.1175/1520-0485(2000)030<0090:POTPDT>2.0.CO;2 |
_version_ |
1766131589019860992 |