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Antarctic Bottom Water sensitivity to spatio-temporal variations in Antarctic meltwater fluxes
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  • Wilton Aguiar,
  • Sang-Ki Lee,
  • Hosmay Lopez,
  • Shenfu Dong,
  • Helene Seroussi,
  • Daniel C Jones
Wilton Aguiar
CIMAS - Cooperative Institute for Marine and Atmospheric Studies

Corresponding Author:[email protected]

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Sang-Ki Lee
Atlantic Oceanographic and Meteorological Laboratory (NOAA)
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Hosmay Lopez
Atlantic Oceanographic and Meteorological Laboratory
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Shenfu Dong
NOAA/AOML
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Helene Seroussi
Dartmouth College
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Daniel C Jones
British Antarctic Survey
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Abstract

Ice sheet melting into the Southern Ocean can change the formation and properties of the Antarctic Bottom Water (AABW). Climate models generally mimic ice sheet melting by adding uniformly-distributed freshwater fluxes in the Southern Ocean. Uniform fluxes misrepresent the heterogeneous Antarctic ice sheet melting patterns, and could bias AABW representation in models. We use a global ocean and sea-ice model to explore whether the spatial distribution and increases in freshwater fluxes can alter AABW properties, formation, and the Antarctic sea-ice area. We find that a realistic spatially varying flux sustains AABW with higher salinities compared to simulations with uniform meltwater fluxes. Finally, we show that a ~ 20% increase in ice sheet melting can trigger AABW freshening and Antarctic sea-ice expansion rates similar to those observed in the Southern Ocean since 1980, suggesting that the increasing Antarctic meltwater discharge can drive the observed AABW freshening and the Antarctic sea-ice expansion.