Cooling and ventilating the abyssal ocean

Publication Type  Journal Article
Year of Publication  2001
Authors  Orsi, A. H.; Jacobs, S. S.; Gordon, A. L.; Visbeck, M.
Journal Title  Geophysical Research Letters
Volume  28
Issue  15
Pages  2923-2926
Journal Date  Aug 1
ISBN Number  0094-8276
Accession Number  ISI:000170157400013
Key Words  deep-water formation; weddell sea; bottom water; southern-ocean; circulation; masses; land
Abstract  

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 approximate to 2 degreesC 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 20(th) -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.

Notes  

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