Publication Date:
2022-05-26
Description:
Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Ocean 119 (2014): 1068–1083, doi:10.1002/2013JC009470.
Description:
In the tropical eastern South Pacific the Stratus Ocean Reference Station (ORS) (∼20°S, 85.5°W) is located in the transition zone between the oxygen minimum zone (OMZ) and the well-oxygenated subtropical gyre. In February/March 2012, extremely anomalous water mass properties were observed in the thermocline at the Stratus ORS. The available eddy oxygen anomaly was −10.5 × 1016 µmol. This anomalous water was contained in an anticyclonic mode-water eddy crossing the mooring site. This eddy was absorbed at that time by an anticyclonic feature located south of the Stratus mooring. This was the largest water property anomaly observed at the mooring during the 13.5 month deployment period. The sea surface height anomaly (SSHA) of the strong mode-water eddy in February/March 2012 was weak, and while the lowest and highest SSHA were related to weak eddies, SSHA is found not to be sufficient to specify the eddy strength for subsurface-intensified eddies. Still, the anticyclonic eddy, and its related water mass characteristics, could be tracked backward in time in SSHA satellite data to a formation region in April 2011 off the Chilean coast. The resulting mean westward propagation velocity was 5.5 cm s−1. This extremely long-lived eddy carried the water characteristics from the near-coastal Chilean water to the open ocean. The water mass stayed isolated during the 11 month travel time due to high rotational speed of about 20 cm s−1 leading to almost zero oxygen in the subsurface layer of the anticyclonic mode-water eddy with indications of high primary production just below the mixed layer.
Description:
Financial support was received
through Woods Hole Oceanographic
Institution (R.A.W. and S.B.) and the
GEOMAR (L.S. and R.C). The Stratus
Ocean Reference Station is supported
by the National Oceanic and
Atmospheric Administration’s (NOAA)
Climate Observation Program
(NA09OAR4320129). This work is a
contribution of the DFG-supported
project SFB754 (http://www.sfb754.de)
which is supported by the Deutsche
Forschungsgemeinschaft.
Description:
2014-08-12
Keywords:
Anticyclonic eddy
;
Deoxygenation
;
Stratus mooring
;
Oxygen anomaly
Repository Name:
Woods Hole Open Access Server
Type:
Article
Format:
application/pdf
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