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Abstract

Antarctic Bottom Water supplies the deep limb of the global overturning circulation and ventilates the abyssal ocean. Antarctic Bottom Water has warmed, freshened, and contracted in recent decades, but the causes remain poorly understood. We use unique multiyear observations from the continental shelf and deep ocean near the Mertz Polynya to examine the sensitivity of this bottom water formation region to changes on the continental shelf, including the calving of a large iceberg. Postcalving, the seasonal cycle of Dense Shelf Water (DSW) density almost halved in amplitude and the volume of DSW available for export reduced. In the deep ocean, the density and volume of Adelie Land Bottom Water decreased sharply after calving, while oxygen concentrations remained high, indicating continued ventilation by DSW. This natural experiment illustrates how local changes in forcing over the Antarctic continental shelf can drive large and rapid changes in the abyssal ocean.

Item Type:	Article
Authors/Creators:	Snow, K and Rintoul, SR and Sloyan, BM and Hogg, AMC
Keywords:	Antarctic bottom water, iceberg calving, dense shelf water, polynya, surface forcing
Journal or Publication Title:	Geophysical Research Letters
Publisher:	Amer Geophysical Union
ISSN:	0094-8276
DOI / ID Number:	https://doi.org/10.1002/2017GL076195
Copyright Information:	© 2018 Commonwealth of AustraliaJournal © American Geophysical Union
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