Biomathematics Seminar Series - Kolja Kypke

Speaker: Kolja Kypke, University of Guelph

Title: Rate-induced tipping and chaos in the Greenland ice sheet

Abstract: The Greenland ice sheet is an important element of the Earth’s climate system and is a central climate component for studying the phenomenon of abrupt changes in its overall state due to small changes in external forcing, commonly known as tipping. The contemporary Greenland ice sheet in a state-of-the-art model is demonstrated to exhibit a novel mode of variability, namely that of oscillating ice streams, under mild external atmospheric forcing. The result of increasing this external forcing at different rates is that the time before tipping occurs can vary by tens to hundreds of millennia. The delay of the tipping depends sensitively on the initial condition and the rate of forcing, implying chaotic variability.  A conceptual model of coupled oscillating ice streams is constructed and analyzed to validate the chaotic nature of the variability seen in the comprehensive model. This model displays various transitions to chaos, including period doubling, intermittency, and attractor crises, as well as chaotic transients similar to those that are proposed to delay the tipping in the comprehensive model.

For a list of upcoming Biomathematics Seminars please visit the following website https://mathstat.uoguelph.ca/node/414