Impact of Sea Ice Production off Sabrina Coast, East Antarctica
Alejandro H. Orsi, Cynthia Webb
Abstract
Abstract Sea ice production is critical to ocean overturning. Brine released within Antarctic polynyas transforms surface water into denser Shelf Water (SW). In spite of the persistent Dalton Polynya, SW is absent off Sabrina Coast. To explain its passive role in‐situ and remote datasets for 2003–2015 are analyzed. Combined volume export near the shelf break and inshore volume change render an average sea ice production of 197.41 km 3 per year (4.6 m/yr productivity), highly correlated (0.95) to divergent interior sea ice motion. Meltwater input of 157.5 Gt/yr is required to match the salinity of a prominent subsurface Thermostad measured in 2014–2015. SW formed during 2003–2008 but halted in 2009–2011, when summer sea ice divergence and export were at a minimum (<10 km 3 ), significantly freshening the Thermostad (−5.07 ΔS per decade). Large sea ice export (>30 km 3 ) increased its salinity (2.16 ΔS per decade) since 2012.