| Summary: | Coastal polynyas in the Ross Sea are important source regions of high-salinity shelf water (HSSW) - the precursor of Antarctic Bottom Water thatsupplies the lower limb of the thermohaline circulation. Here, the responseof sea ice production and HSSW formation to synoptic-scale and mesoscalecyclones was investigated for the Ross Ice Shelf Polynya (RISP) using acoupled ocean-sea ice-ice shelf model targeted on the Ross Sea. Whensynoptic-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 inthe offshore and onshore winds. HSSW formation mainly occurred in thewestern RISP and was enhanced responding to the SIP increase under bothtypes of cyclones. Promoted HSSW formation could persist for 12-60 h after the decay of the cyclones. The HSSW exports across the DrygalskiTrough and the Glomar Challenger Trough were positively correlated with themeridional wind. Such correlations are mainly controlled by variations ingeostrophic ocean currents that result from sea surface elevation change and density differences. Peer reviewed
|
|---|