Department of Geological and Atmospheric Sciences (GE-AT)

Stable Isotope Paleo Environments Research Group (SIPERG)

Research Highlights

The role of ocean circulation in regulating North Atlantic climate

Research Questions:

  • How influential was the surface Atlantic meridional overturning circulation (AMOC) in shaping the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) climate intervals in the North Atlantic sector (e.g., Lund et al., 2006; Denton and Broecker, 2008)?
  • Is the AMOC behaviour during the last 1000 years consistent with the phase of the North Atlantic Oscillation (NAO) (e.g., Trouet et al., 2009)? If so, are they dynamically coupled?
  • Are the marine radiocarbon reservoir ages (reported here as Delta R values) north of Iceland coupled with AMOC dynamics during the last millennium?

Surface changes in the North Atlantic meridional overturning circulation during the last millennium (Nature Communications article)

Click here for details regarding the figure caption.

Major findings: From our article: "Our findings indicate a declining influence of NAC waters on the North Icelandic shelf during the last millennium. Since circa AD 1940, NAC-derived surface waters have again become more influential north of Iceland and within the Arctic, resembling hydrographic conditions present during the early MCA. We infer that the surface AMOC was relatively strong in Medieval times, became weaker in the LIA, and strengthened again after circa AD 1940. We suggest that the surface component of the AMOC amplified the relatively warm conditions during the MCA and the relatively cool conditions during the LIA within the North Atlantic Ocean."