High-resolution modeling of the Eastern Tropical Pacific oxygen minimum zone: Sensitivity to the tropical oceanic circulation

Type Article
Date 2014-08
Language English
Author(s) Montes IvonneORCID1, 2, 3, Dewitte BorisORCID1, Gutknecht Elodie1, Paulmier Aurelien1, 4, Dadou Isabelle1, Oschlies AndreasORCID2, Garcon Veronique1
Affiliation(s) 1 : CNRS CNES UPS IRD, Lab Etud Geophys & Oceanog Spatiales, UMR 5566, Toulouse, France.
2 : GEOMAR Helmholtz Ctr Ocean Res, Kiel, Germany.
3 : IGP, Lima, Peru.
4 : Inst Mar IMARPE, Callao, Peru.
Source Journal Of Geophysical Research-oceans (2169-9275) (Amer Geophysical Union), 2014-08 , Vol. 119 , N. 8 , P. 5515-5532
DOI 10.1002/2014JC009858
WOS© Times Cited 33
Abstract

The connection between the equatorial mean circulation and the oxygen minimum zone (OMZ) in the Eastern Tropical Pacific is investigated through sensitivity experiments with a high-resolution coupled physical-biogeochemical model. A validation against in situ observations indicates a realistic simulation of the vertical and horizontal oxygen distribution by the model. Two sets of climatological open-boundary conditions for the physical variables, which differ slightly with respect to the intensity and vertical structure of the Equatorial Current System, are shown to lead to contrasting characteristics of the simulated OMZ dynamics. From a Lagrangian perspective, the mean differences near the coast originate to a large extent from the different transport of deoxygenated waters by the secondary Tsuchiya Jet (secondary Southern Subsurface Countercurrent, sSSCC). The O-2 budget further indicates a large difference in the balance between tendency terms, with advection exhibiting the largest difference between both simulations, which is shown to result from both linear and nonlinear advection. At regional scale, we also find that the variability of the physical contribution to the rate of O-2 change is one order of magnitude larger than the variability associated with the biogeochemical contribution, which originates from internal high-frequency variability. Overall our study illustrates the large sensitivity of the OMZ dynamics to the equatorial circulation.

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Montes Ivonne, Dewitte Boris, Gutknecht Elodie, Paulmier Aurelien, Dadou Isabelle, Oschlies Andreas, Garcon Veronique (2014). High-resolution modeling of the Eastern Tropical Pacific oxygen minimum zone: Sensitivity to the tropical oceanic circulation. Journal Of Geophysical Research-oceans, 119(8), 5515-5532. Publisher's official version : https://doi.org/10.1002/2014JC009858 , Open Access version : https://archimer.ifremer.fr/doc/00688/79998/