Transiting consolidated ice strongly influenced polynya area during a shrink event in Terra Nova Bay in 2013

Abstract

Coastal polynyas in Antarctica are a window of air-sea energy exchange and an important source of Antarctic Bottom Water production. However, the relationship between the polynya area variation and the surrounding marine environment is yet to be fully understood. Here we quantify the influence of the volume of transiting consolidated ice on the Terra Nova Bay Polynya area with ice thickness data. Changes in transiting consolidated ice volume are shown to dominate the evolution and variation of the polynya during a typical polynya shrinking event that occurred between 19 June to 03 July, 2013, rather than katabatic winds or air temperature, which are commonly assumed to be the main drivers. Over the cold seasons from 2013 to 2020, the Terra Nova Bay Polynya area is highly correlated to the transiting consolidated ice volume. We demonstrate that thick transiting ice limits the polynya area by blocking the newly-formed sea ice from leaving.