Baroclinic Ocean Response to Climate Forcing Regulates Decadal Variability of Ice-Shelf Melting in the Amundsen Sea
- 1Ocean and Earth Science, University of Southampton, Southampton, UK
- 2British Antarctic Survey, Cambridge, UK
- 3Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, UK
- 4Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA
- 5CSIRO Oceans & Atmosphere, Hobart, TAS, Australia, 6Centre for Southern Hemisphere Oceans Research, Hobart, TAS, Australia
- 6Centre for Southern Hemisphere Oceans Research, Hobart, TAS, Australia
- 7Australian Antarctic Program Partnership, University of Tasmania, Hobart, TAS, Australia
- 8Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, The Netherlands
- 9Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands
- 10Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, UK
Warm ocean waters drive rapid ice-shelf melting in the Amundsen Sea. The ocean heat transport toward the ice shelves is associated with the Amundsen Undercurrent, a near-bottom current that flows eastward along the shelf break and transports warm waters onto the continental shelf via troughs. Here we use a regional ice-ocean model to show that, on decadal time scales, the undercurrent's variability is baroclinic (depth-dependent). Decadal ocean surface cooling in the tropical Pacific results in cyclonic wind anomalies over the Amundsen Sea. These wind anomalies drive a westward perturbation of the shelf-break surface flow and an eastward anomaly (strengthening) of the undercurrent, leading to increased ice-shelf melting. This contrasts with shorter time scales, for which surface current and undercurrent covary, a barotropic (depth-independent) behavior previously assumed to apply at all time scales. This suggests that interior ocean processes mediate the decadal ice-shelf response in the Amundsen Sea to climate forcing.
How to cite: SIlvano, A., Holland, P., Naugthen, K., Dragomir, O., Dutrieux, P., Jenkins, A., Si, Y., Stewart, A., Peña Molino, B., Janzing, G., Dotto, T., and Naveira Garabato, A.: Baroclinic Ocean Response to Climate Forcing Regulates Decadal Variability of Ice-Shelf Melting in the Amundsen Sea, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8902, https://doi.org/10.5194/egusphere-egu23-8902, 2023.
