Project Description:
The Atlantic Meridional Overturning Circulation (AMOC) is the large-scale circulation in the Atlantic Ocean that transports heat and salt from the tropics to North Atlantic. Its strength is strongly influence by changes in water mass properties. In the past, the release of freshwater from the melting Greenland glaciers into the North Atlantic has corresponded with a weakening or collapse of the AMOC, raising concerns that the present-day climate system may similarly be approaching an AMOC tipping point. A shutdown of the AMOC would cause massive disruptions to the European and North American climate, but large uncertainties remain regarding the likelihood and impact of such events.
Due to the lack of long-term records of AMOC measurements and inconsistencies in future climate projections, we must turn to the events of the last glacial period (80,000 – 20,000 years ago), such as Dansgaard-Oeschger events (D-O events), to better understand its response to abrupt climate change. D-O events are millennial-scale transitions between warm and cold North Atlantic climates driven by recurring shifts of AMOC regimes. These transitions have been both simulated in theoretical physical models (“box models”) and high-complexity general circulation models, leading to a pool of hypotheses about the mechanisms underlying D-O events.
In this project, the student will attempt to reconcile these different hypotheses by comparing theoretical and climate models. The project will start by solving a simple system of equations derived from a box model of the AMOC, modelling oceanic temperature and salinity fluxes, as well as the impact of the atmosphere on the ocean. The student will then compare the solutions of this system to existing simulations of D-O events obtained from climate models. This comparison will be used to study long-term climate and AMOC oscillations and to assess the validity and range of applications of the so-called Convection-Advection oscillator mechanism.
Pre-requisites:
Supervisory Team:
Marie Sicard
Contact:
Yvan Rome: Y.M.Rome@leeds.ac.uk
How to apply:
- Complete the online REP application form one for each project of interest.
- Email a copy of your CV to yes-dtn@leeds.ac.uk (only once is needed).
- Complete the EDI Form (only one is needed). Although this is optional, if places are over-subscribed, preference will be given to under-represented groups, as defined above.