Antarctic Bottom Water Formation

Antarctic Bottom Water (AABW) formation is the production of the densest water in the global ocean around the Antarctic margin, the cold abyssal limb of the meridional overturning circulation. Sea ice growth in coastal polynyas, mainly in the Weddell and Ross Seas, rejects brine into shelf water already near the surface freezing point, raising salinity and density until the water sinks down the continental slope, entraining ambient water as it descends. The product spreads northward below roughly 4000 m at temperatures near minus 0.5 to plus 0.5 degrees C. AABW ventilates the deep ocean and sets abyssal oxygen and carbon storage.