Cooling and ventilating the Abyssal Ocean
Article first published online: 7 DEC 2012
Copyright 2001 by the American Geophysical Union.
Geophysical Research Letters
Volume 28, Issue 15, pages 2923–2926, 1 August 2001
How to Cite
- Issue published online: 7 DEC 2012
- Article first published online: 7 DEC 2012
- Manuscript Accepted: 7 MAY 2001
- Manuscript Received: 4 JAN 2001
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.