Oxygen variance and meridional oxygen supply in the Tropical North East Atlantic oxygen minimum zone

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Autores principales: Hahn, Johannes, Brandt, Peter, Greatbatch, Richard J, Krahmann, Gerd, Körtzinger, Arne
Formato: Dataset Open Access
Lenguaje:en
Publicado: PANGAEA 2015
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author Hahn, Johannes
Brandt, Peter
Greatbatch, Richard J
Krahmann, Gerd
Körtzinger, Arne
author_facet Hahn, Johannes
Brandt, Peter
Greatbatch, Richard J
Krahmann, Gerd
Körtzinger, Arne
collection Datos científicos de ciencias marinas y ambientales
contents The distribution of the mean oceanic oxygen concentration results from a balance between ventilation and consumption. In the eastern tropical Pacific and Atlantic, this balance creates extended oxygen minimum zones (OMZ) at intermediate depth. Here, we analyze hydrographic and velocity data from shipboard and moored observations, which were taken along the 23°W meridian cutting through the Tropical North East Atlantic (TNEA) OMZ, to study the distribution and generation of oxygen variability. By applying the extended Osborn-Cox model, the respective role of mesoscale stirring and diapycnal mixing in producing enhanced oxygen variability, found at the southern and upper boundary of the OMZ, is quantified. From the well-ventilated equatorial region toward the OMZ core a northward eddy-driven oxygen flux is observed whose divergence corresponds to an oxygen supply of about 2.4 µmol kg-1 year-1 at the OMZ core depth. Above the OMZ core, mesoscale eddies act to redistribute low- and high-oxygen waters associated with westward and eastward currents, respectively. Here, absolute values of the local oxygen supply >10 mmol kg-1 year-1 are found, likely balanced by mean zonal advection. Combining our results with recent studies, a refined oxygen budget for the TNEA OMZ is derived. Eddy-driven meridional oxygen supply contributes more than 50 % of the supply required to balance the estimated oxygen consumption. The oxygen tendency in the OMZ, as given by the multidecadal oxygen decline, is maximum slightly above the OMZ core and represents a substantial imbalance of the oxygen budget reaching about 20 % of the magnitude of the eddy-driven oxygen supply.
format Dataset Open Access
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institution PANGAEA
language en
publishDate 2015
publisher PANGAEA
record_format pangaea
spellingShingle Oxygen variance and meridional oxygen supply in the Tropical North East Atlantic oxygen minimum zone
Hahn, Johannes
Brandt, Peter
Greatbatch, Richard J
Krahmann, Gerd
Körtzinger, Arne
Climate - Biogeochemistry Interactions in the Tropical Ocean; SFB754
The distribution of the mean oceanic oxygen concentration results from a balance between ventilation and consumption. In the eastern tropical Pacific and Atlantic, this balance creates extended oxygen minimum zones (OMZ) at intermediate depth. Here, we analyze hydrographic and velocity data from shipboard and moored observations, which were taken along the 23°W meridian cutting through the Tropical North East Atlantic (TNEA) OMZ, to study the distribution and generation of oxygen variability. By applying the extended Osborn-Cox model, the respective role of mesoscale stirring and diapycnal mixing in producing enhanced oxygen variability, found at the southern and upper boundary of the OMZ, is quantified. From the well-ventilated equatorial region toward the OMZ core a northward eddy-driven oxygen flux is observed whose divergence corresponds to an oxygen supply of about 2.4 µmol kg-1 year-1 at the OMZ core depth. Above the OMZ core, mesoscale eddies act to redistribute low- and high-oxygen waters associated with westward and eastward currents, respectively. Here, absolute values of the local oxygen supply >10 mmol kg-1 year-1 are found, likely balanced by mean zonal advection. Combining our results with recent studies, a refined oxygen budget for the TNEA OMZ is derived. Eddy-driven meridional oxygen supply contributes more than 50 % of the supply required to balance the estimated oxygen consumption. The oxygen tendency in the OMZ, as given by the multidecadal oxygen decline, is maximum slightly above the OMZ core and represents a substantial imbalance of the oxygen budget reaching about 20 % of the magnitude of the eddy-driven oxygen supply.
title Oxygen variance and meridional oxygen supply in the Tropical North East Atlantic oxygen minimum zone
topic Climate - Biogeochemistry Interactions in the Tropical Ocean; SFB754
url https://doi.org/10.1594/PANGAEA.843317