Estimation of Sea Ice Production in the Bering Sea From AMSR‐E and AMSR2 Data, With Special Emphasis on the Anadyr Polynya

We created, for the first time, a map of sea ice production in the Bering Sea, based on thin‐ice thickness data from the Advanced Microwave Scanning Radiometers (AMSR‐E and AMSR2) with a heat flux calculation. We used the AMSR‐E thin‐ice algorithm developed for the Arctic Ocean with some modification. We provided a 16‐yr data set of ice production from the 2002/2003 to 2018/2019 seasons, excepting the 2011/2012 season. It is found that the Anadyr polynya has by far the highest sea ice production (average of 93 km3/yr) and accounts for more than 30% of all polynya ice production in the Bering Sea. The combined ice production in the Anadyr, Anadyr Strait, and St. Lawrence polynyas becomes the second‐largest ice production during the AMSR‐E period in the Northern Hemisphere. It is considered that the high ice production in the Anadyr polynya produces cold, saline, nutrient‐rich water, so‐called Anadyr Water, which would contribute to the formation of the cold halocline layer and high biological productivity. The ice production in the Anadyr polynya shows very large year‐to‐year variability. The record low ice extent year of the 2017/2018 season is also the lowest ice production year; the production is only one tenth of the highest value, observed during the 2015/2016 season. The high sensitivity of the wind direction and strength to the location of the Aleutian Low causes this large variability. We also built reconstruction schemes of ice production in the polynyas, using the offshore wind and air temperature, by multiple linear regression. Plain Language Summary Coastal polynyas are areas of high sea ice production and brine (high‐salinity water) rejection from ice formation there produces dense water. The dense water formed by polynya ice production in the Bering Sea likely contributes to the formation of the cold halocline layer (CHL). The CHL is a major subsurface water mass that contributes to the maintenance of circumstances suitable for sea ice formation in the Arctic Ocean. Further, the dense water results in deep/intermediate water formation, which might temporarily occur in the present day and dominantly occurred during glacial periods. We estimated polynya ice production in the entire Bering Sea for the first time based on satellite data and a heat flux calculation. The Anadyr polynya with its adjacent polynyas exhibits the second‐largest ice production in the Northern Hemisphere. Coastal polynyas in the Bering Sea show very large year‐to‐year vari