Southern Ocean Circulation and Climate Variability
Event: 2017 Ocean Surface Topography Science Team Meeting
Session: Science II: Large Scale Ocean Circulation Variability and Change
Presentation type: Type Oral
Contribution: PDF file
The SO plays a major role in global ocean circulation, a system of surface and deep currents, linking all oceans and one of the fundamental determinants of the Earth’s climate. The Southern Ocean (SO) has been subject to many climatic discussions, capable of transporting vast amounts of salt, heat, and nutrients to help regulate to global climate. Recent climatic studies aim to better understand the SO influence towards a shifting climate. This work discusses the importance of the Antarctic Circumpolar Current (ACC), as well as the role of the strong Westerlies on the ACC. Using nearly 25 years’ worth of satellite-derived altimetry data, the interannual and spatio-temporal trends of sea surface height (SSH) and geostrophic currents were explored. Our work focuses on the relationship of surface winds (cross-calibrated Multi-Platform Ocean Surface Wind Vector Analyses) to further convey the role of the Westerlies on the SSH and surface currents. To understand the interannual to decadal variability in SO ocean circulation and transports we used eddy-resolving model simulations from Southern Ocean State Estimate (SOSE) and German-contribution to the Estimating the Circulation and Climate of the Ocean systems (GECCO2) simulations. Our preliminary results are supporting the intensification and southward shifting ACC currents. Additionally, waters at mid-depth (upper 1000m) in the SO have increased in temperature at a faster rate than the average rate for the entire global ocean. Due to the rapid warming of the SO, the thermohaline circulation will be affected as the ocean becomes warmer and atmospheric patterns shift, as well as a weakening overturning circulation.