Mapping of sea ice production for Antarctic coastal polynyas

Active sea‐ice production in Antarctic coastal polynyas causes dense water formation, finally leading to Antarctic Bottom Water (AABW) formation. This study gives the first mapping of sea ice production in the Antarctic Ocean, based on heat‐flux calculation with ice thickness data derived from satellite data. The highest ice production occurs in the Ross Ice Shelf Polynya region. The ice production there decreased by ∼30% from the 1990s to the 2000s, which can be one candidate for causing the recent freshening of AABW. The Cape Darnley polynya in East Antarctica is found to be the second highest production area, suggesting a possible AABW formation area. According to our estimation, around 10% of Southern Ocean sea ice is produced in the major Antarctic coastal polynyas. The mapping provides surface heat‐ and salt‐flux conditions in the ice‐covered region, which have not been well understood.