| Type |
Article |
| Date |
2016-03 |
| Language |
English |
| Author(s) |
Sevellec Florian1, Huck Thierry2 |
| Affiliation(s) |
1 : Univ Southampton, Natl Oceanog Ctr Southampton, Ocean & Earth Sci, Southampton SO14 3ZH, Hants, England.
2 : Lab Phys Oceans UMR 6523 CNRS IFREMER IRD UBO, Brest, France. |
| Source |
Journal Of Physical Oceanography (0022-3670) (Amer Meteorological Soc), 2016-03 , Vol. 46 , N. 3 , P. 895-917 |
| DOI |
10.1175/JPO-D-14-0148.1 |
| WOS© Times Cited |
2 |
| Keyword(s) |
Meridional overturning circulation, Thermohaline circulation, Atm/Ocean Structure/ Phenomena, Ocean circulation, Baroclinic flows, Geographic location/entity, Ekman pumping, Circulation/ Dynamics, Atlantic Ocean |
| Abstract |
It is typically assumed that the meridional density gradient in the North Atlantic is well and positively correlated with the Atlantic meridional overturning circulation (AMOC). In numerical "water-hosing" experiments, for example, imposing an anomalous freshwater flux in the Northern Hemisphere leads to a slowdown of the AMOC. However, on planetary scale, the first-order dynamics are linked to the geostrophic balance, relating the north-south pressure gradient to the zonal circulation. In this study, these two approaches are reconciled. At steady state and under geostrophic dynamics, an analytical expression is derived to relate the zonal and meridional pressure gradient. This solution is only valid where the meridional density gradient length scale is shorter than Earth's curvature length scale, that is, north of 35 degrees N. This theoretical expression links the north-south density gradient to the AMOC and can be used as a closure for zonally averaged ocean models. Assumptions and shortcomings of the approach are presented. Implications of these results for paleoclimate problems such as AMOC collapse and asymmetry in the meridional overturning circulation of the Atlantic and of the Pacific are discussed. |
| Full Text |
| File |
Pages |
Size |
Access |
| Publisher's official version |
23 |
3 MB |
Open access |
|
