Change in dense shelf water and Adelie land bottom water precipitated by iceberg calving

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 she...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Snow, K, Rintoul, SR, Sloyan, BM, Hogg, AMC
Format: Article in Journal/Newspaper
Language:English
Published: Amer Geophysical Union 2018
Subjects:
Earth Sciences
Oceanography
Physical Oceanography
Antarctic
The Antarctic
Adelie Land
Antarc*
Iceberg*
Online Access:https://doi.org/10.1002/2017GL076195
http://ecite.utas.edu.au/131899
Description
Summary: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.

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