Open Polynya

An open polynya is a persistent area of open water or thin ice within the pack or fast ice that stays open through processes that fight freeze-up. Sensible-heat (open) polynyas are held open by an upwelling flux of warm ocean water from below, the term contrasting with latent-heat (coastal) polynyas that wind drives by pushing ice away. The Southern Ocean Weddell and Maud Rise polynyas are the classic open-water cases. Polynyas are sites of intense heat loss, dense-water and brine production, and high biological output, and they offer ice-free passage and access water that ships and observing platforms use.