C42B-05:
Multi-Model Comparison of Southern Ocean and Sea Ice Trends in CORE-II and CMIP5 Model
Thursday, 18 December 2014: 11:20 AM
Stephanie M Downes, Australian National University, Canberra, ACT, Australia, Stephen Matthew Griffies, NOAA Geophysical Fluid Dynamics Laboratory, Prinnceton, NJ, United States, Riccardo Farneti, ICTP, Earth System Physics Section, Trieste, Italy, Simon J Marsland, CSIRO, Aspendale, Australia, Petteri Uotila, Finnish Meteorological Institute, Helsinki, Finland and Andrew Hogg, Australian National University, Canberra, Australia
Abstract:
The Southern Ocean circulation, influenced by buoyancy, momentum and sea ice processes, varies on seasonal to centennial timescales. Incomplete spatio-temporal observations of the full ocean water column, overlying ocean-ice-atmosphere fluxes, and adjacent polar dynamics challenge our ability to model the Southern Ocean. However, several studies have indicated this region is particularly important in the evolving climate, including the anthropogenic influences. Models coherently capture large-scale Southern Ocean patterns, however it is the magnitude and location of these patterns that varies widely. In particular, difficulties with modelling of small scale processes remains an outstanding issue. Here we review the representation of the Southern Ocean circulation, including fluxes at the ocean-ice and ocean-atmosphere interfaces, in numerous coupled climate models from two international modeling efforts, namely the Coordinated Ocean-ice Reference Experiments Phase II (CORE-II) and Coupled Model Intercomparison Project Phase 5 (CMIP5). We focus on the relationships between large scale and mesoscale overturning circulation, formation of key water masses and the associated deep winter mixed layers, buoyancy and wind fluxes, and sea ice. We identify major uncertainties in the modelling of past, present and projected large-scale ocean processes, and provide insights for future modelling directions.
