ACDC Seminar by Robbin Bastiaansen on the 19th of November

On the 19th of November at 16:00, Robbin Bastiaansen (Universiteit Utrecht) will give an Amsterdam Dynamics Seminar. We will go for drinks at Bar Boele after the talk.

The talk will take place in the Maryam seminar room (9A-46).

Title:  Tipping in spatially extended systems: detection, prediction and control

Abstract: In the current Anthropocene, there is a need to better understand the catastrophic effects that climate and land-use change may have on ecosystems, earth system components and the whole Earth system. The concept of tipping points and critical transitions contributes to this understanding. Tipping occurs in a system when it is forced outside the basin of attraction of the original equilibrium, resulting in a critical transition to an alternative, often less-desirable, stable state. The general belief and intuition, based on simple conceptual models of tipping elements (i.e. ordinary differential equations), is that tipping leads to reorganization of the full (sub)system. However, in spatially extended systems the tipping behaviour might be more subtle due to the presence of additional spatially heterogeneous states (such as Turing patterns or coexistence states). In such spatially extended systems, the crossing of a bifurcation might lead only to a slight restructuring of the system or to a tipping event in which only part of the spatial domain undergoes reorganization, limiting the impact of these events on the system's functioning.

 In this talk, I will focus on three research projects on spatially extended systems. First, I will discuss a study on detecting abrupt transitions in output of the IPCC-informing global climate models, in which we have used an edge detection algorithm to obtain all abrupt shifts in the CMIP6 database. Second, I will talk about a new data-driven method to distinguish imminent Turing bifurcations from Tipping bifurcations based on estimated dispersion relations for reaction-diffusion equations, thus providing an extension to common early warning signs by also signaling for the kind of bifurcation that is approached. Finally, I will discuss work on spatially heterogeneous Allen-Cahn type equations that explores using pattern formation theory and optimisation techniques how in spatially heterogeneous systems, local preventive measures might stop tipping dynamics via e.g. front pinning.

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