@article{fdi:010080329,
  title = {{A} decomposition of the {A}tlantic meridional overturning circulation into physical components using {I}ts sensitivity to vertical diffusivity},
  author = {{M}ignot, {J}uliette  and {L}evermann, {A}. and {G}riesel, {A}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he sensitivity of the {A}tlantic {O}cean meridional overturning circulation to the vertical diffusion coefficient {K} in the global coupled atmosphere-ocean-sea ice model {CLIMBER}-3 alpha is investigated. {A}n important feature of the three-dimensional ocean model is its low-diffusive tracer advection scheme. {T}he strength {M}-max of the {A}tlantic overturning is decomposed into three components: 1) the flow {M}-s exported southward at 30 degrees {S}, 2) the large-scale upward flow that balances vertical diffusion in the {A}tlantic, and 3) a wind-dependent upwelling flux {W}-bound along the {A}tlantic boundaries that is not due to vertical diffusion. {T}he export of water at 30 degrees {S} varies only weakly with kappa, but is strongly correlated with the strength of the overflow over the {G}reenland-{S}cotland ridge. {T}he location of deep convection is found to be mixing dependent such that a shift from the {N}ordic seas to the {I}rminger {S}ea is detected for high values of kappa. {T}he ratio {R} = {M}-s/{M}-max gives a measure of the interhemispheric overturning efficiency and is found to decrease linearly with {K}. {T}he diffusion-induced upwelling in the {A}tlantic is mostly due to the uniform background value of kappa while parameterization of enhanced mixing over rough topography and in stratified areas gives only a weak contribution to the overturning strength. {I}t increases linearly with kappa. {T}his is consistent with the classic 2/3 scaling law only when taking the linear variation of the density difference to kappa into account. {T}he value of {W}-bound is roughly constant with kappa but depends linearly on the wind stress strength in the {N}orth {A}tlantic. {T}he pycnocline depth is not sensitive to changes in kappa in the model used herein, and the results suggest that it is primarily set by the forcing of the {S}outhern {O}cean winds. {T}he scaling of the total overturning strength with kappa depends on the combined sensitivity of each of the terms to kappa. {I}n the range of background diffusivity values in which no switch in deep convection sites is detected, {M}-max scales linearly with the vertical diffusivity. {I}t is argued that scalings have, in general, to be interpreted with care because of the generally very small range of kappa but also because of possible shifts in important physical processes such as deep convection location.},
  keywords = {{CIRCULATION} {OCEANIQUE} ; {COUPLAGE} {OCEAN} {ATMOSPHERE} ; {MODELISATION} ; {CONVECTION} ; {UPWELLING} ; {ATLANTIQUE}},
  booktitle = {},
  journal = {{J}ournal of {P}hysical {O}ceanography, {A}merican {M}eteorological {S}ociety},
  volume = {36},
  numero = {4},
  pages = {636--650},
  ISSN = {0022-3670},
  year = {2006},
  DOI = {10.1175/{JPO}2891.1},
  URL = {https://www.documentation.ird.fr/hor/fdi:010080329},
}