Open AccessAntarctic density stratification and the strength of the circumpolar current during the Last Glacial Maximum
Author(s) -
LynchStieglitz Jean,
Ito Takamitsu,
Michel Elisabeth
Publication year - 2016
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1002/2015pa002915
Subject(s) - stratification (seeds) , circumpolar star , last glacial maximum , oceanography , ocean current , geology , climatology , glacial period , antarctic bottom water , physical oceanography , climate change , circumpolar deep water , sverdrup , thermohaline circulation , environmental science , north atlantic deep water , arctic , paleontology , seed dormancy , botany , germination , dormancy , holocene , biology
The interaction between ocean circulation and biological processes in the Southern Ocean is thought to be a major control on atmospheric carbon dioxide content over glacial cycles. A better understanding of stratification and circulation in the Southern Ocean during the Last Glacial Maximum (LGM) provides information that will help us to assess these scenarios. First, we evaluate the link between Southern Ocean stratification and circulation states in a suite of climate model simulations. While simulated Antarctic Circumpolar Current (ACC) transport varies widely (80–350 Sverdrup (Sv)), it co‐varies with horizontal and vertical stratification and the formation of the southern deep water. We then test the LGM simulations against available data from paleoceanographic proxies, which can be used to assess the density stratification and ACC transport south of Australia. The paleoceanographic data suggest a moderate increase in the Southern Ocean stratification and the ACC strength during the LGM. Even with the relatively large uncertainty in the proxy‐based estimates, extreme scenarios exhibited by some climate models with ACC transports of greater than 250 Sv and highly saline Antarctic Bottom Water are highly unlikely.