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Major role of the equatorial current system in setting oxygen levels in the eastern tropical Atlantic Ocean: A high‐resolution model study
Author(s) -
Duteil Olaf,
Schwarzkopf Franziska U.,
Böning Claus W.,
Oschlies Andreas
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2013gl058888
Subject(s) - oxygen , environmental science , biogeochemical cycle , current (fluid) , oceanography , ocean current , atmospheric sciences , climatology , tropical atlantic , antarctic bottom water , boundary current , water mass , geology , sea surface temperature , ecology , physics , quantum mechanics , biology
Understanding the causes of the observed expansion of tropical ocean's oxygen minimum zones (OMZs) is hampered by large biases in the representation of oxygen distribution in climate models, pointing to incorrectly represented mechanisms. Here we assess the oxygen budget in a global biogeochemical circulation model, focusing on the Atlantic Ocean. While a coarse (0.5°) configuration displays the common bias of too large and too intense OMZs, the oxygen concentration in an eddying (0.1°) configuration is higher and closer to observations. This improvement is traced to a stronger oxygen supply by a more realistic representation of the equatorial and off‐equatorial undercurrents, outweighing the concurrent increase in oxygen consumption associated with the stronger nutrient supply. The sensitivity of the eastern tropical Atlantic oxygen budget to the equatorial current intensity suggests that temporal changes in the eastward oxygen transport from the well‐oxygenated western boundary region might partly explain variations in the OMZs.