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Changes in the Subduction of Southern Ocean Water Masses at the End of the Twenty-First Century in Eight IPCC Models
Citation
Downes, S and Bindoff, NL and Rintoul, SR, Changes in the Subduction of Southern Ocean Water Masses at the End of the Twenty-First Century in Eight IPCC Models, Journal of Climate, 23, (24) pp. 6526-6541. ISSN 0894-8755 (2010) [Refereed Article]
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Copyright Statement
Copyright © 2010 American Meteorological Society
Official URL: http://www.ametsoc.org
DOI: doi:10.1175/2010JCLI3620.1
Abstract
A multimodel comparison method is used to assess the sensitivity of Subantarctic Mode Water (SAMW)
and Antarctic Intermediate Water (AAIW) formation to climate change. For the Intergovernmental Panel on
Climate Change A2 emissions scenario (where atmospheric CO2 is 860 ppm at 2100), the models show
cooling and freshening on density surfaces less than about 27.4 kg m23, a pattern that has been observed in
the late twentieth century. SAMW (defined by the low potential vorticity layer) and AAIW (defined by the
salinity minimum layer) warm and freshen as they shift to lighter density classes. Heat and freshwater fluxes at
the ocean surface dominate the projected buoyancy gain at outcrop regions of SAMW and AAIW, whereas
the net increase in the Ekman flux of heat and freshwater contributes to a lesser extent. This buoyancy gain,
combined with shoaling of the winter mixed layer, reduces the volume of SAMW subducted into the ocean
interior by a mean of 8 Sv (12%), and the subduction of AAIW decreases by a mean of 14 Sv (23%; 1 Sv [
106 m3 s21). Decreases in the projected subduction of the key Southern Ocean upper-water masses imply
a slow down in the Southern Ocean circulation in the future, driven by surface warming and freshening. A
reduction in the subduction of intermediate waters implies a likely future decrease in the capacity of the
Southern Ocean to sequester CO2.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Research Division: | Earth Sciences |
| Research Group: | Oceanography |
| Research Field: | Physical oceanography |
| Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
| Objective Group: | Understanding climate change |
| Objective Field: | Climate variability (excl. social impacts) |
| UTAS Author: | Downes, S (Dr Stephanie Downes) |
| UTAS Author: | Bindoff, NL (Professor Nathan Bindoff) |
| UTAS Author: | Rintoul, SR (Dr Steve Rintoul) |
| ID Code: | 68291 |
| Year Published: | 2010 |
| Web of Science® Times Cited: | 37 |
| Deposited By: | IMAS Research and Education Centre |
| Deposited On: | 2011-03-10 |
| Last Modified: | 2011-05-22 |
| Downloads: | 413 View Download Statistics |
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