Investigating the controls on Atlantic Overturning: Insights from the Last Interglacial

Investigating the controls on Atlantic Overturning: Insights from the Last Interglacial

Variations in the Atlantic Meridional Overturning Circulation (AMOC) can have dramatic impacts on regional and global climate. Furthermore, the AMOC is likely to change in the future in response to an enhanced hydrologic cycle and ice melting, with far-reaching climate impacts. This project seeks to provide a deeper understanding of the mechanisms and dynamics of AMOC changes by examining the behaviour of one of its key components during the previous warm period 116-129 kyr BP (MIS5e).
This project will generate and interpret interglacial-length grain-size records in cores from high accumulation rate sediments under the main path of the Iceland-Scotland (I-S) overflow, which makes up approximately 1/3rd of the deep flow of the AMOC. The project will involve laboratory work based in UCL Geography, processing marine sediments and analyzing samples on the Coulter Counter for grain size. Quantitative, statistical analysis of the results will be conducted. Specific questions to be addressed include: How does Iceland-Scotland overflow vary during MIS 5e? Does it vary in response to freshwater input and/or changes in the Nordic Seas? Does behaviour mimic that seen during the Holocene? Are results consistent with climate model simulations? What inferences do the results have for future AMOC changes?

Reading:
D. J. R. Thornalley et al (2013). Long-term variations in Iceland–Scotland overflow strength during the Holocene. Climate of the Past, 9, 1-12, doi:10.5194/cp-9-1-2013.
P. Bakker et al (2012). Sensitivity of the North Atlantic climate to Greenland Ice Sheet melting during the Last Interglacial. Climate of the Past 8, 995-1009, doi: 10.5194/cp-8-995-2012.

This project is suitable for hybrid working.