Cooling and ventilating the abyssal ocean

The abyssal ocean is filled with cold, dense waters that sink along the Antarctic continental slope and overflow sills that lie south of the Nordic Seas. Recent integrations of chlorofluorocarbon‐11 (CFC) measurements are similar in Antarctic Bottom Water (AABW) and in lower North Atlantic Deep Wate...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Orsi, A., Jacobs, S., Gordon, A., Visbeck, Martin
Format: Article in Journal/Newspaper
Language:English
Published: AGU (American Geophysical Union) 2001
Subjects:
Antarctic
Southern Ocean
The Antarctic
Antarc*
NADW
Nordic Seas
North Atlantic Deep Water
North Atlantic
Online Access:https://oceanrep.geomar.de/id/eprint/1609/
https://oceanrep.geomar.de/id/eprint/1609/1/2001GL012830.pdf
https://doi.org/10.1029/2001GL012830
Description
Summary:The abyssal ocean is filled with cold, dense waters that sink along the Antarctic continental slope and overflow sills that lie south of the Nordic Seas. Recent integrations of chlorofluorocarbon‐11 (CFC) measurements are similar in Antarctic Bottom Water (AABW) and in lower North Atlantic Deep Water (NADW), but Antarctic inputs are ≈ 2°C colder than their northern counterparts. This indicates comparable ventilation rates from both polar regions, and accounts for the Southern Ocean dominance over abyssal cooling. The decadal CFC‐based estimates of recent ventilation are consistent with other hydrographic observations and with longer‐term radiocarbon data, but not with hypotheses of a 20th‐century slowdown in the rate of AABW formation. Significant variability is not precluded by the available ocean measurements, however, and interannual to decadal changes are increasingly evident at high latitudes.

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