FN Archimer Export Format
PT J
TI Geostrophic Closure of the Zonally Averaged Atlantic Meridional Overturning Circulation
BT 
AF SEVELLEC, Florian
   HUCK, Thierry
AS 1:1;2:2;
FF 1:;2:;
C1 Univ Southampton, Natl Oceanog Ctr Southampton, Ocean & Earth Sci, Southampton SO14 3ZH, Hants, England.
   Lab Phys Oceans UMR 6523 CNRS IFREMER IRD UBO, Brest, France.
C2 UNIV SOUTHAMPTON, UK
   CNRS, FRANCE
UM LOPS
IF 3.13
TC 2
UR https://archimer.ifremer.fr/doc/00323/43456/42843.pdf
LA English
DT Article
DE ;Meridional overturning circulation;Thermohaline circulation;Atm/Ocean Structure/ Phenomena;Ocean circulation;Baroclinic flows;Geographic location/entity;Ekman pumping;Circulation/ Dynamics;Atlantic Ocean
AB 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.
PY 2016
PD MAR
SO Journal Of Physical Oceanography
SN 0022-3670
PU Amer Meteorological Soc
VL 46
IS 3
UT 000371476500006
BP 895
EP 917
DI 10.1175/JPO-D-14-0148.1
ID 43456
ER

EF