Talk by Guido Vettoretti

Slow and Fast Physics of the Dansgaard-Oeschger Relaxation Oscillation

The dominant mode of millennial scale glacial climate variability is governed by D-O oscillations, which are especially prominent during Marine Isotopic Stage 3 (MIS3). I will describe how perennial paleocrystic Arctic sea ice that may have been present during much of MIS3 may be instrumental in shaping the slow timescale evolution of the D-O transition from interstadial to stadial periods. Further insight into the fast timescale mechanisms underlying the rapid transition from stadial to interstadial will also demonstrate the important role of sea ice-ocean dynamics in the Polar basin. The modelled interaction between the transport and budgets of freshwater and heat in the coupled ocean, atmosphere, land and sea ice system will provide evidence that the D-O oscillation is a coupled hydro-thermohaline oscillator. However, I will attempt to demonstrate that to first order a relaxation salt oscillator dominates the majority of the millennial scale glacial climate variability.

Guido Vettoretti is from the Earth, Atmospheric, and Planetary Physics Group, Department of Physics, University of Toronto.