The atmospheric effects of Southern Ocean open-ocean polynyas onto the coastal polynyas from EC-Earth3

Abstract: Polynyas are recurring areas of open water or thin ice within the sea ice pack, which alter the local oceanatmosphere heat and moisture exchange. They are differentiated as coastal (latent heat) or open-ocean (sensible heat) polynya according to their formation process. Coastal polynyas are critical sources of dense water and formation of Antarctic BottomWater (AABW) following the brine enrichment of surface waters during sea-ice formation, and are easily influenced by local atmosphere conditions. However, few studies have examined the atmospheric response of open-ocean polynyas onto the coastal polynyas given the fact that open-ocean polynyas have capacity to re-adjust atmospheric circulation. To better understand the surrounding impact of large openocean polynya events, output from CMIP6 historical experiment synoptic scale EC-Earth3 is adapted. The results show an increased coastal polynya frequency and extent occurring with more active open-ocean polynya years in the Weddell Sea. The findings can to a degree be explained by near-surface air temperature and wind speed differences in the coastal regions, which are found statistically significant between most and least active open-ocean polynya years. There are however still uncertainties regarding the representation of highlatitude ocean and atmosphere processes in global coupled models. Still, the findings contribute to a better understanding of coastal polynya opening processes, as well as how we might expect to see the different type of polynya interact by their influence and dependence on surrounding atmospheric conditions.