CO2-Induced Ocean Warming of the Antarctic Continental Shelf in an Eddying Global Climate Model

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Goddard, Paul B., Dufour, Carolina O., Yin, J., Griffies, Stephen M., Winton, Michael
• Other Authors: Univ Arizona, Dept Geosci, Department of Geosciences; University of Arizona; Tucson AZ USA, Atmospheric and Oceanic Sciences Program; Princeton University; Princeton NJ USA, Geophysical Fluid Dynamics Laboratory; NOAA; Princeton NJ USA
• Format: Article in Journal/Newspaper
• Language: English
• Published: AMER GEOPHYSICAL UNION 2017
• Subjects: eddying climate model; Antarctica shelf warming; Antarctica shelf freshening; Antarctic; Southern Ocean; The Antarctic; Antarc*; Antarctica; Ice Sheet; Ice Shelves
• Online Access: http://hdl.handle.net/10150/626296; https://doi.org/10.1002/2017JC012849

Ocean warming near the Antarctic ice shelves has critical implications for future ice sheet mass loss and global sea level rise. A global climate model with an eddying ocean is used to quantify the mechanisms contributing to ocean warming on the Antarctic continental shelf in an idealized 2xCO(2) experiment. The results indicate that relatively large warm anomalies occur both in the upper 100 m and at depths above the shelf floor, which are controlled by different mechanisms. The near-surface ocean warming is primarily a response to enhanced onshore advective heat transport across the shelf break. The deep shelf warming is initiated by onshore intrusions of relatively warm Circumpolar Deep Water (CDW), in density classes that access the shelf, as well as the reduction of the vertical mixing of heat. CO2-induced shelf freshening influences both warming mechanisms. The shelf freshening slows vertical mixing by limiting gravitational instabilities and the upward diffusion of heat associated with CDW, resulting in the buildup of heat at depth. Meanwhile, freshening near the shelf break enhances the lateral density gradient of the Antarctic Slope Front (ASF) and disconnect isopycnals between the shelf and CDW, making cross-ASF heat exchange more difficult. However, at several locations along the ASF, the cross-ASF heat transport is less inhibited and heat can move onshore. Once onshore, lateral and vertical heat advection work to disperse the heat anomalies across the shelf region. Understanding the inhomogeneous Antarctic shelf warming will lead to better projections of future ice sheet mass loss. National Oceanic and Atmospheric Administration (NOAA) CPO project [NA13OAR4310128]; National Science Foundation [OPP-1513411]; University of Arizona faculty startup funding; University of Arizona Department of Geosciences; National Aeronautics and Space Administration (NASA) [NNX14AL40G]; Princeton Environmental Institute (PEI) Grand Challenge initiative; Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) project under the National Science Foundation [PLR-1425989] Green Open Access: AGU allows final articles to be placed in an institutional repository 6 months after publication. / 6 month embargo; Published online 25 OCT 2017 This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [e-mail].