The critical values for the metrics were chosen to define distinct geographical areas or hot spots consistent with the existence of polynyas at Hell Gate and Dundas Island, without restricting hot spots to those areas.
Polynya Metric Polynyas Category Sensible heat metric Lambert Channel, (2) Committee Bay, (4) Fury and Velocity metric and Hecla Strait, (8) Dundas Island, (16) Hell Gate-Cardigan Strait, (17) Needs further tidal Franklin Strait, (9) Bellot Strait, (10) modeling Prince Regent Inlet, (11) Queens Channel and Penny Strait (15) Unlikely to be Lancaster Sound, (12) Viscount Melville related to tidal Sound, (13) Lady Ann Strait, (18) Coburg currents Island, (20) Bylot Island (19)
The polynyas at Hell Gate and Cardigan Strait and Dundas Island have been previously identified as ones where tidal mixing makes a substantial contribution to the sensible heat flux (Topham et al, 1983; Smith et al.
1983) found evidence that the Dundas Island polynya expanded during periods of spring (strong) tides and froze over during neap (weak) tides after periods of very cold air temperatures.
However, in the maps of median ice concentration as a function of time of year (Environment Canada, 2002), the polynyas at Hell Gate and Cardigan Strait, Dundas Island, Penny Strait and Queens Channel, and Lambert Channel are evident as areas of low ice concentration compared to the surrounding ocean.