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Observational Evidence of Ventilation Hotspots in the Southern Ocean

Dove, Lilian A. and Thompson, Andrew F. and Balwada, Dhruv and Gray, Alison R. (2021) Observational Evidence of Ventilation Hotspots in the Southern Ocean. Journal of Geophysical Research. Oceans, 126 (7). Art. No. e2021JC017178. ISSN 2169-9275. doi:10.1029/2021jc017178. https://resolver.caltech.edu/CaltechAUTHORS:20210701-141800445

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Abstract

Standing meanders are a key component of the Antarctic Circumpolar Current (ACC) circulation system, and numerical studies have shown that these features may locally enhance subduction, upwelling, as well as lateral and vertical tracer transport. Yet, observational data from these regions remain sparse. Here, we present results based on measurements made by a group of autonomous platforms sampling an ACC standing meander formed due to the interaction of the Polar Front with the Southwest Indian Ridge. Two Seagliders were deployed alongside a Biogeochemical-Argo float that was advected through the standing meander. In the high eddy kinetic energy region of the standing meander, the glider observations reveal enhanced submesoscale frontal gradients as well as heightened tracer variability at depth, as compared to the more quiescent region further downstream. Vertical gradients in spice and apparent oxygen utilization are reduced in the standing meander despite similarities in the large-scale vertical stratification, suggesting greater ventilation of the surface ocean. These observations are consistent with numerical studies that highlight standing meanders as hotspots for ventilation and subduction due to enhanced mesoscale stirring and submesoscale vertical velocities. Our results emphasize the need to account for spatial heterogeneity in processes influencing air-sea exchange, carbon export, and biogeochemical cycling in the Southern Ocean.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1029/2021jc017178DOIArticle
https://www.ncei.noaa.gov/archive/accession/0228185Related ItemGlider data
https://www.ncei.noaa.gov/archive/accession/0228187Related ItemGlider data
ORCID:
AuthorORCID
Dove, Lilian A.0000-0001-8346-0034
Thompson, Andrew F.0000-0003-0322-4811
Balwada, Dhruv0000-0001-6632-0187
Gray, Alison R.0000-0002-1644-7654
Additional Information:© 2021 American Geophysical Union. Issue Online: 19 July 2021; Version of Record online: 19 July 2021; Accepted manuscript online: 26 June 2021; Manuscript accepted: 24 June 2021; Manuscript revised: 18 May 2021; Manuscript received: 10 January 2021. The authors are grateful to the captain and crew of the R/V Thomas G. Thompson as well as A. Orsi, L. Talley, I. Rosso, G. Viglione, and M. Kotz for their assistance in deploying the gliders during the 2019 I06S GO-SHIP cruise. The authors thank D. Swift, S. Riser, and the SOCCOM executive team for increasing sampling frequency of the BCG-Argo float during the SOGOS mission. LAD and AFT were supported by NSF award OCE-1756956 and the David and Lucille Packard Foundation. LAD was additionally supported by an NSF Graduate Research Fellowship. DB and ARG were supported by NSF award OCE-1756882; ARG received additional support from NASA through award NNX80NSSC19K1252 and from the U.S. Argo Program through NOAA grant NA15OAR4320063. Data Availability Statement: The glider data are archived at NOAA's National Centers for Environmental information and can be accessed at https://www.ncei.noaa.gov/archive/accession/0228185 and https://www.ncei.noaa.gov/archive/accession/0228187. Data from the BGC-Argo float were collected and made freely available by the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Project funded by the National Science Foundation, Division of Polar Programs (NSF PLR-1425989 and OPP-1936222), supplemented by NASA, and by the International Argo Program and the NOAA programs that contribute to it (http://www.argo.ucsd.edu, http://argo.jcommops.org). The Argo Program is part of the Global Ocean Observing System.
Funders:
Funding AgencyGrant Number
NSFOCE-1756956
David and Lucille Packard FoundationUNSPECIFIED
NSF Graduate Research FellowshipUNSPECIFIED
NSFOCE-1756882
NASANNX80NSSC19K1252
National Oceanic and Atmospheric Administration (NOAA)NA15OAR4320063
NSFPLR-1425989
NSFOPP-1936222
Subject Keywords:submesoscale; standing meander; Polar Front; ventilation; Southern Ocean; export
Issue or Number:7
DOI:10.1029/2021jc017178
Record Number:CaltechAUTHORS:20210701-141800445
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210701-141800445
Official Citation:Dove, L. A., Thompson, A. F., Balwada, D., & Gray, A. R. (2021). Observational evidence of ventilation hotspots in the Southern Ocean. Journal of Geophysical Research: Oceans, 126, e2021JC017178. https://doi.org/10.1029/2021JC017178
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109690
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:02 Jul 2021 20:10
Last Modified:26 Jul 2021 22:15

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