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Connecting Antarctic sea ice to deep‐ocean circulation in modern and glacial climate simulations
Author(s) -
Marzocchi Alice,
Jansen Malte F.
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl073936
Subject(s) - geology , oceanography , sea ice , shutdown of thermohaline circulation , ocean current , glacial period , climatology , cryosphere , ice sheet , antarctic sea ice , deep sea , antarctic ice sheet , lead (geology) , north atlantic deep water , thermohaline circulation , paleontology
Antarctic sea‐ice formation plays a key role in shaping the abyssal overturning circulation and stratification in all ocean basins, by driving surface buoyancy loss through the associated brine rejection. Changes in Antarctic sea ice have therefore been suggested as drivers of major glacial‐interglacial ocean circulation rearrangements. Here, the relationship between Antarctic sea ice, buoyancy loss, deep‐ocean stratification, and overturning circulation is investigated in Last Glacial Maximum and preindustrial simulations from the Paleoclimate Modelling Intercomparison Project (PMIP). The simulations show substantial intermodel differences in their representation of the glacial deep‐ocean state and circulation, which is often at odds with the geological evidence. We argue that these apparent inconsistencies can largely be attributed to differing (and likely insufficient) Antarctic sea‐ice formation. Discrepancies can be further amplified by short integration times. Deep‐ocean equilibration and sea‐ice representation should, therefore, be carefully evaluated in the forthcoming PMIP4 simulations.