Connecting Antarctic sea ice to deep‐ocean circulation in modern and glacial climate simulations. Issue 12 (17th June 2017)

• Record Type: Journal Article
• Authors: Marzocchi, Alice; Jansen, Malte F.
• Is Part Of: Geophysical research letters. Volume 44:Issue 12(2017)
• Page Start: 6286
• Page End: 6295
• Publication Date: 2017-06-17
• Subjects: LGM -- PMIP -- AMOC -- Antarctic -- sea ice -- stratification; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2017GL073936
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: 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. Key Points: Antarctic sea ice, buoyancy loss, abyssal stratification, and ocean overturning circulation are related across glacial and modern simulations Insufficient sea ice formation and short integration times lead to discrepancies between different glacial climate simulations and paleodata