PHY-05 Southern Ocean heat uptake and transport in a changing climate
The response of sea ice and high salinity shelf water in the Ross Ice Shelf Polynya to cyclonic atmosphere circulations
Xiaoqiao Wang* , School of Oceanography, Shanghai Jiao Tong University, Shanghai, China.
Zhaoru Zhang, School of Oceanography, Shanghai Jiao Tong University, Shanghai, China.
Michael S. Dinniman, Center for Coastal Physical Oceanography, Old Dominion University, Norfolk, VA 23529, USA.
Petteri Uotila, Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland.
Xichen Li, International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
Meng Zhou, School of Oceanography, Shanghai Jiao Tong University, Shanghai, China.

Coastal polynyas in the Ross Sea are important source regions of high salinity shelf water (HSSW) – the precursor of Antarctic Bottom Water that supplies the lower limb of the thermohaline circulation. Here, the response of sea ice production and HSSW formation to synoptic- and meso-scale cyclones were investigated for the Ross Ice Shelf Polynya (RISP) using a coupled ocean-sea ice-ice shelf model targeted on the Ross Sea. When synoptic-scale cyclones prevailed over RISP, sea ice production (SIP) increased rapidly by 20–30% over the entire RISP. During the passage of mesoscale cyclones, SIP increased by about 2 times over the western RISP but decreased over the eastern RISP, resulting respectively from enhancement in the offshore and onshore winds. HSSW formation mainly occurred in the western RISP and was enhanced responding to the SIP increase under both types of cyclones. Promoted HSSW formation could persist for 12–48 hours after the decay of the cyclones. The HSSW export across the Drygalski Trough was negatively correlated with the meridional wind speed, while the export across the Glomar Challenger Trough was positively correlated with the meridional wind. Such correlations are mainly controlled by variations in geostrophic ocean currents that result from sea surface elevation change.