Mechanisms of Atlantic Meridional Overturning Circulation variability simulated by the NEMO model
We have investigated mechanisms for the Atlantic Meridional Overturning Circulation (AMOC) variability at 26.5° N (other than the Ekman component) that can be related to external forcings, in particular wind variability. Resolution dependence is studied using identical experiments with 1° and 1/4° N...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2014-07-01
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| Series: | Ocean Science |
| Online Access: | http://www.ocean-sci.net/10/645/2014/os-10-645-2014.pdf |
| _version_ | 1818031687442890752 |
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| author | V. N. Stepanov K. Haines |
| author_facet | V. N. Stepanov K. Haines |
| author_sort | V. N. Stepanov |
| collection | DOAJ |
| description | We have investigated mechanisms for the Atlantic Meridional Overturning
Circulation (AMOC) variability at 26.5° N (other than the Ekman
component) that can be related to external forcings, in particular wind
variability. Resolution dependence is studied using identical experiments
with 1° and 1/4° NEMO model runs over 1960–2010.
<br><br>
The analysis shows that much of the variability in the AMOC at
26° N can be related to the wind strength over the North Atlantic, through
mechanisms lagged on different timescales. At ~ 1-year lag the
January–June difference of mean sea level pressure between high and
mid-latitudes in the North Atlantic explains 35–50% of the interannual
AMOC variability (with negative correlation between wind strength and AMOC).
At longer lead timescales ~ 4 years, strong (weak) winds over the
northern North Atlantic (specifically linked to the NAO index) are followed
by higher (lower) AMOC transport, but this mechanism only works in the
1/4° model. Analysis of the density correlations suggests an increase
(decrease) in deep water formation in the North Atlantic subpolar gyre to be
the cause. Therefore another 30% of the AMOC variability at 26° N can be
related to density changes in the top 1000 m in the Labrador and Irminger
seas occurring ~ 4 years earlier. |
| first_indexed | 2024-12-10T05:55:26Z |
| format | Article |
| id | doaj.art-7ac8db010baf453fac5ede2e6d5b42a3 |
| institution | Directory Open Access Journal |
| issn | 1812-0784 1812-0792 |
| language | English |
| last_indexed | 2024-12-10T05:55:26Z |
| publishDate | 2014-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Ocean Science |
| spelling | doaj.art-7ac8db010baf453fac5ede2e6d5b42a32022-12-22T01:59:56ZengCopernicus PublicationsOcean Science1812-07841812-07922014-07-0110464565610.5194/os-10-645-2014Mechanisms of Atlantic Meridional Overturning Circulation variability simulated by the NEMO modelV. N. Stepanov0K. Haines1Dept. of Meteorology, University of Reading, Reading, UKDept. of Meteorology, University of Reading, Reading, UKWe have investigated mechanisms for the Atlantic Meridional Overturning Circulation (AMOC) variability at 26.5° N (other than the Ekman component) that can be related to external forcings, in particular wind variability. Resolution dependence is studied using identical experiments with 1° and 1/4° NEMO model runs over 1960–2010. <br><br> The analysis shows that much of the variability in the AMOC at 26° N can be related to the wind strength over the North Atlantic, through mechanisms lagged on different timescales. At ~ 1-year lag the January–June difference of mean sea level pressure between high and mid-latitudes in the North Atlantic explains 35–50% of the interannual AMOC variability (with negative correlation between wind strength and AMOC). At longer lead timescales ~ 4 years, strong (weak) winds over the northern North Atlantic (specifically linked to the NAO index) are followed by higher (lower) AMOC transport, but this mechanism only works in the 1/4° model. Analysis of the density correlations suggests an increase (decrease) in deep water formation in the North Atlantic subpolar gyre to be the cause. Therefore another 30% of the AMOC variability at 26° N can be related to density changes in the top 1000 m in the Labrador and Irminger seas occurring ~ 4 years earlier.http://www.ocean-sci.net/10/645/2014/os-10-645-2014.pdf |
| spellingShingle | V. N. Stepanov K. Haines Mechanisms of Atlantic Meridional Overturning Circulation variability simulated by the NEMO model Ocean Science |
| title | Mechanisms of Atlantic Meridional Overturning Circulation variability simulated by the NEMO model |
| title_full | Mechanisms of Atlantic Meridional Overturning Circulation variability simulated by the NEMO model |
| title_fullStr | Mechanisms of Atlantic Meridional Overturning Circulation variability simulated by the NEMO model |
| title_full_unstemmed | Mechanisms of Atlantic Meridional Overturning Circulation variability simulated by the NEMO model |
| title_short | Mechanisms of Atlantic Meridional Overturning Circulation variability simulated by the NEMO model |
| title_sort | mechanisms of atlantic meridional overturning circulation variability simulated by the nemo model |
| url | http://www.ocean-sci.net/10/645/2014/os-10-645-2014.pdf |
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