Abstract: Using daily AMSR-E sea ice concentration data from 2003 to 2011, the area of Alaska Coastal Polynyas in the Chukchi Sea was studied. According to the characteristics of these polynyas, threshold method was proposed to identify each polynya. Frequency of polynyas occurrence was also used to delimit the maximum range of polynyas in the studied region. Based on the information extracted from Alaska Coastal Polynyas, the temporal and spatial variations and their major influence factors were studied. To eliminate the effect of the open sea on the identification of polynyas, the analysis was limited between January and April when Bering Strait was totally covered by sea ice. The following conclusions were drawn: Every winter, five polynyas will appear along the Alaska Coastal area and are almost parallel to the coastline. In addition to the typical coastal polynyas, flaw polynyas tend to appear off landfast ice in the vicinity of Barrow Point in late March and April. Daily changes in polynya areas were dominated on synoptic scale, which is further related to the wind directions. Seaward winds favored the formation of coastal polynyas, but since northeast and north winds prevail in the studied region, polynya sites are sometimes closed or diminished in extent for up to a few weeks. Under the effect of northerly winds, Pacific Inflow has virtually no effect on the northern polynyas but has an important influence on the spatial distribution of southern polynyas along Alaska coastal area.

Key words: polynya, sea ice concentration, Chukchi Sea, Alaska, Arctic