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Cooling and ventilating the Abyssal Ocean
Author(s) -
Orsi Alejandro H.,
Jacobs Stanley S.,
Gordon Arnold L.,
Visbeck Martin
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2001gl012830
Subject(s) - antarctic bottom water , abyssal zone , oceanography , hydrography , north atlantic deep water , geology , weddell sea bottom water , sill , sink (geography) , water mass , continental shelf , climatology , antarctic intermediate water , bottom water , environmental science , thermohaline circulation , sea ice , ice shelf , cryosphere , cartography , geochemistry , geography
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 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.