Eastern Pacific oxygen minimum zones: Supply paths and multidecadal changes.

Stramma, Lothar , Johnson, Gregory C., Firing, Eric and Schmidtko, Sunke (2010) Eastern Pacific oxygen minimum zones: Supply paths and multidecadal changes. Open Access Journal of Geophysical Research: Oceans, 115 (C9). C09011. DOI 10.1029/2009JC005976.

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Abstract

The supply of oxygen-rich water to the oxygen minimum zones (OMZs) of the eastern North and South Pacific via zonal tropical currents is investigated using shipboard acoustic Doppler current profiler and hydrographic section data. Near the equator, the Equatorial Undercurrent (EUC), Northern and Southern Subsurface Countercurrents (SCCs), and the Northern and Southern Intermediate Countercurrents (ICCs) all carry water that is oxygen richer than adjacent westward flows, thereby providing a net oxygen supply to the eastern Pacific OMZs. The synoptic velocity-weighted oxygen concentration difference between eastward and westward flows is typically 10–50 μmol kg−1. Subthermocline zonal oxygen fluxes reflect decreasing oxygen concentrations of the EUC, the SCCs, and the ICCs as they flow eastward. Approximately 30 year time series in well-sampled regions of the equatorial Pacific show oxygen content decreasing as rapidly as −0.55 μmol kg−1 yr−1 in the major oxygen supply paths of the OMZs for a 200–700 m layer and similar trends for a density layer spanning roughly these depths. This finding is in gross agreement with climate models, which generally predict expanding OMZs.

Document Type: Article
Keywords: Oceanography; ocean oxygen minima, oxygen supply; eastern Pacific
Research affiliation: OceanRep > SFB 754 > A5
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-PO Physical Oceanography
OceanRep > SFB 754
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1029/2009JC005976
ISSN: 2169-9275
Projects: SFB754
Expeditions/Models/Experiments:
Date Deposited: 20 Sep 2010 06:04
Last Modified: 16 Jan 2018 09:47
URI: http://oceanrep.geomar.de/id/eprint/8903

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