PHY-05 Southern Ocean heat uptake and transport in a changing climate
Dynamics for cross-slope exchanges of water masses in the Ross Sea, Antarctica
Yuanjie Chen* , School of Oceanography, Shanghai Jiao Tong University, Shanghai, China
Zhaoru Zhang, School of Oceanography, Shanghai Jiao Tong University, Shanghai, China; Key Laboratory for Polar Science, Polar Research Institute of China, Ministry of Natural Resources, Shanghai, China
Xiaohui Liu, State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
Michael S. Dinniman, Center for Coastal Physical Oceanography, Old Dominion University, Norfolk, Virginia 23529, United States of America
Zhiqiang Liu, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
Meng Zhou, School of Oceanography, Shanghai Jiao Tong University, Shanghai, China; Key Laboratory for Polar Science, Polar Research Institute of China, Ministry of Natural Resources, Shanghai, China

Oceanic exchange across the steep slope of the Ross Sea has a critical impact not only on physical and biological processes of the Ross Sea shelf, but also on the global meridional overturning circulation. This study quantifies the volume transport of circumpolar deep water (CDW) and dense shelf water (DSW) across the Ross Sea slope and elucidates the mechanisms responsible for the exchanges using a coupled ocean-sea ice-ice shelve model at eddy-resolving resolution. Momentum balance analysis indicates that the onshore transport of CDW is geostrophically controlled by along-isobath pressure gradient force. Offshore transport of DSW is driven by the ageostrophic pressure gradient force that is contributed by advection and viscosity along the isobath. Vorticity balance analysis shows that vortex squeezing associated with upslope transport is driven by advection of relative vorticity in the CDW layer, and the vortex stretching associated with downslope transport is driven by the curl of viscosity in the bottom DSW layer.