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Deep argo reveals bottom water properties and pathways in the Australian-Antarctic Basin


Foppert, A and Rintoul, SR and Purkey, SG and Zilberman, N and Kobayashi, T and Sallee, J-B and van Wijk, EM and Wallace, LO, Deep argo reveals bottom water properties and pathways in the Australian-Antarctic Basin, JGR Oceans, 126, (12) Article e2021JC017935. ISSN 2169-9275 (2021) [Refereed Article]

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2021. American Geophysical Union. All Rights Reserved.

DOI: doi:10.1029/2021JC017935


Changes in properties and quantity of Antarctic Bottom Water (AABW) have major implications for the climate system, through sequestration of heat and carbon into, and ventilation of, the abyssal ocean. Yet, it remains one of the most difficult water masses to observe. An array of 12 Deep Argo floats, capable of profiling from the surface to the seafloor and under sea ice, provides a new perspective on AABW in the Australian-Antarctic Basin. Over 2years of data from the floats illuminate AABW properties with unprecedented detail, simultaneously sampling AABW at multiple locations, year-round, throughout the basin. Calibrating each float individually with nearby, quasi-simultaneous shipboard profiles ensures the highest quality salinity data, with estimated accuracy of 0.005 or better. Pathways of Ross Sea and Adlie Land Bottom Water (RSBW and ALBW), defined by their unique temperature and salinity characteristics, are mapped along the continental slope from their respective sources. The main pathway of RSBW, identified by its characteristic deep salinity maximum, is inferred to be inshore of the 3,700m isobath, where it cools and freshens westward along the slope before interacting with ALBW near 140E. A pulse of very cold and very fresh (nearly −0.6C, 34.82gkg−1) ALBW appears in February 2019, highlighting temporal variability on daily scales near its source. Deep Argo has greatly enhanced our view of AABW in the Australian-Antarctic Basin and will prove to be an essential tool for monitoring future changes in the deep ocean by drastically increasing observations in a cost-effective way.

Item Details

Item Type:Refereed Article
Keywords:Antarctic Bottom Water, deep-ocean variability, abyssal circulation, Deep Argo
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical oceanography
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Antarctic and Southern Ocean oceanic processes
UTAS Author:Foppert, A (Dr Annie Foppert)
UTAS Author:Rintoul, SR (Dr Steve Rintoul)
UTAS Author:van Wijk, EM (Ms Esmee van Wijk)
UTAS Author:Wallace, LO (Dr Luke Wallace)
ID Code:148629
Year Published:2021
Web of Science® Times Cited:4
Deposited By:Australian Antarctic Program Partnership
Deposited On:2022-01-31
Last Modified:2022-08-24
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