Investigation of Polynya Area in the Arctic Using Morphology Image-Processing Techniques

Arctic coastal polynyas, defined here as persistent openings in the winter sea ice pack, are significant areas for ocean-atmosphere heat exchange, high winter sea ice production with resulting brine rejection and the dependence of local ecosystems. It is therefore critical to accurately quantify polynya area to understand their spatial and temporal variability, particularly in the context of recent dramatic Arctic sea ice declines. In this study, a erosion algorithm (a morphology image-processing technique) is applied to AMSR-E (Advanced Microwave Scanning Radiometer-EOS) sea ice concentrations in the Arctic during January-December from 2003 to 2010 to remove regions with low sea ice concentrations in the marginal ice zone and obtain sea ice pack regions with low sea ice concentrations in polynyas. The daily time series of water area within polynyas are extracted by a water integration method after sea ice concentrations are preprocessed using the morphology image-processing techniques. Based on the water area within polynyas, the monthly and interannual variability of all polynyas in the Arctic is studied.