Modeling sea ice production and dense shelf water formation in coastal polynyas around East Antarctica

Abstract

Using an ice‐ocean coupled model with fine horizontal resolution around East Antarctica, sea ice production and dense shelf water (DSW) formation in coastal polynyas are investigated. The model reproduces well the locations of coastal polynyas and the high sea ice production there. DSW is formed over the continental shelves under a number of coastal polynyas. A threshold density, beyond which net production of DSW takes place, is largely different among coastal polynyas. The densest and most vigorous DSW formation occurs in the Cape Darnley and Mertz‐Ninnis Glacier polynyas followed by somewhat less but still significant DSW formation in the Prydz‐Barrier and Vincennes polynyas. Assuming mixing of the DSW outflowing across the shelf break with typical Modified Circumpolar Deep Water over the continental slope, the maximum possible formation rate of Antarctic Bottom Water (AABW) is estimated to be 7.58 Sv around East Antarctica between 60°E and 150°E, with the Cape Darnley and Mertz‐Ninnis Glacier polynyas exhibiting the most active formation rates of 2.13 and 1.97 Sv, respectively. From a series of numerical experiments, it is found that the treatment of coastline and grounded icebergs has a large impact on both sea ice production and formation of DSW and AABW.