Deglacial Evolution of Atlantic Mid-Depth and Intermediate-Depth Water Variability

Delia Oppo, WHOI, Geology and Geophysics, Woods Hole, United States, Geoffrey Gebbie, Woods Hole Oceanographic Institution, Physical Oceanography, Woods Hole, United States, Kuo-Fang Huang, Academia Sinica, Institute of Earth Sciences, Taipei, Taiwan, Weifu Guo, Woods Hole Oceanographic Inst., Woods Hole, United States, Andreas Schmittner, Oregon State University, College of Earth, Ocean, and Atmospheric Sciences, Corvallis, United States, Zhengyu Liu, The Ohio State University, Department of Geography, Columbus, United States and William B Curry, Bermuda Institute of Ocean Sciences, St.George's, GE, Bermuda
Abstract:
Deglacial variations in the Atlantic Meridional Overturning Circulation (AMOC) feature prominently in hypotheses of deglacial climate variability and atmospheric CO2rise. However, there is lingering uncertainty in the glacial deepwater mass configuration (e.g. Gebbie, 2014) and deglacial AMOC variability is even more poorly understood. For example, the deglacial evolution of the contribution of northern and southern source waters to the middle and intermediate depths of the Atlantic is still vigorously debated. Here, we evaluate the evolution of subsurface Atlantic ventilation, emphasizing middle and intermediate depths, by comparing new and published records of water mass variability to output from transient model simulations designed to provide insight into the climatic and oceanographic effects of a dramatic reduction in the AMOC, such as apparently occurred during Heinrich Stadial 1 (Liu et al., 2009; Schmittner and Lund, 2014).

Gebbie, G. (2014), How much did Glacial North Atlantic Water shoal? Paleoceanography, 29, 190–209, doi: 10.1002/2013PA002557.

Liu, Z., B. Otto-Bliesner, F. He, E. Brady, R. Thomas, P. U. Clark, A. E. Carlson, J. Lynch-Stieglitz, W. Curry, E. Brook, D. Erickson, R. Jacob, J. Kutzbach, J., and J. Chen (2009), Transient climate simulation of last deglaciation with a new mechanism for Bølling-Allerød warming, Science, 325, 310-314.

Schmittner, A., and Lund, D. C. (submitted), Carbon Isotopes Support Atlantic Meridional Overturning Circulation Decline as a Trigger for Early Deglacial CO2 rise Climate of the Past Discussions.

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