Return to page

This project is eligible for support from Cardiff Universtiy through the School of Earth & Ocean Sciences.

To apply, please visit the Cardiff University Postgraduate Research portal: http://www.cardiff.ac.uk/for/prospective/postgraduate/applying.html

 Description

Variability in the strength of the Atlantic Meridional Overturning Circulation (AMOC) is a dominant driver, on seasonal to multi-decadal timescales, of the hydrospheric and atmospheric conditions in North America and Europe. Palaeodata has demonstrated the potential of large influxes of fresh water to cause a rapid cessation in the AMOC resulting in significant cooling events (5-10oC) across the northern hemisphere during the last glacial stage. Observation-integrated model predictions of modern climate change suggest that the decrease in the density of surface ocean (due to increased heat content) coupled with the increased influx of fresh water from the retreating Greenland Ice Sheet could lead to an abrupt crash in the AMOC system over the coming 21st century. The consequences of such a crash would be severe. In response NERC have invested £20M in the RAPID/RAPID WATCH program to observe the AMOC over the period 2004-2014. However, hitherto there has been no appropriate long-term high resolution baseline of the natural degree of variability in the AMOC. The primary objective of the studentship is to produce an annually resolved robustly calibrated quantitative reconstruction of the strength of the surface AMOC for the past 1000 years. The student will employ a multiproxy approach combining growth increment width bivalve sclerochronologies with stable and radioisotope geochemistry (δ18O, δ13C and 14C) from a site proximal to the Polar Front (N Iceland) and a site situated in core Atlantic waters (NW Scotland). Preliminary comparison of variability in existing data from the two sites demonstrates that differences in temperature variability across the two sites can be explained by the strength of the AMOC. These data would provide a powerful record of the state of the AMOC before anthropogenic forcings and during key climatological transitions (Medieval Climate Anomaly – Little Ice Age). It is proposed the student will then compare this record with other contemporary palaeoenvironmental data.

Training

Statistical sclerochronological/dendrochronological chronology construction techniques.

Timeseries analysis and palaeoclimate reconstruction techniques.

Stable isotope analysis .

Short course in Radiocarbon dating (run by the NERC radiocarbon facility).

Contact Details

Dr David Reynolds reynoldsd3@cardiff.ac.uk