This is a past event
CADR seminar Friday 25th March at 4pm in the Fraser Noble seminar room (Rm 185). Snacks and refreshments will be served after the talk, giving the opportunity to continue discussions with the speaker. Everyone welcome!
Approaching a dangerous bifurcation, from which a dynamical system (such as the Earth’s climate) will jump to a different alternative attractor, the current stable state is located within a shrinking basin of attraction. The maintenance of the state will, correspondingly, become increasing precarious in the presence of noisy disturbances. We consider an underlying potential, the existence of which is theoretically defined for a saddle-node fold and (via averaging) for a Hopf bifurcation. Close to a stable state, where linear theory prevails, this potential has a parabolic form; but approaching a jump it will become increasingly contaminated by softening nonlinear features. If we have already detected a decrease in the linear decay rate by auto-correlation analysis, the nonlinear information allows us to estimate the propensity for early jumping due to noise. If there is no discernable trend in the linear analysis the nonlinear softening is even more important in showing the (seemingly missed) proximity to an instability. Using geological time series from paleo-climate tipping events (such as the ending of the last ice age) it is shown how these features can be detected to give warning of imminent tipping.
- Speaker
- Prof J Michael T Thompson
- Hosted by
- CADR
- Venue
- FN 185