Polynyas play an important role in climate change with an efficient
exchange of heat and matter between the atmosphere and the ocean in
polar regions. This study investigated the influence of strong tides and
atmospheric forcing on the Amundsen Sea Polynya, especially focusing on
large-area polynya events from 2002 to 2020. We found that the
geographical locations of the polynyas are closely related to the
underwater ridge, where tidal currents are relatively strong. More
importantly, strong cross-ridge winds are the “triggers” above the sea
surface for the initial formation of the Amundsen Sea Polynya, while
strong tides under the sea surface tend to create large-area polynya.
Four of the five largest polynya events occurred mainly during spring
tides. Only the 2016 event occurred during the normal tide period, which
was atmosphere-dominated. Strong tides significantly affect the
evolution of polynyas by strengthening the vertical mixing of seawater.
Given that ocean in Antarctica might become warmer, tidal mixing might
enhance the mixing in the future climate.