On the theory of parallel climate realizations

Tamas Tel (ELTE Budapest)

Jan 24. 2020, 11:00 — 12:00

Based on the theory of ``snapshot/pullback attractors'', we show that important features of the climate change we are observing can be understood by imagining many replicas of the Earth that are not interacting with each other. Their climate systems evolve in parallel, but not in the same way, although they all obey the same physical laws, in harmony with the chaotic-like nature of the climate dynamics. These parallel climate realizations evolving in time can be considered as elements of an ensemble. We argue that the contingency of our Earth's climate system is characterized by the multiplicity of parallel climate realizations rather than by the variability we experience in a time series of our observed past. The natural measure of the snapshot attractor enables one to determine averages and other statistical quantifiers of the climate at any instant of time. In this talk, we review the basic idea for climate changes associated with monotonic drifts, and illustrate the large number of possible applications. Examples are given in a low-dimemsional model and in a numerical climate model of intermediate complexity. We recall that systems undergoing climate change are not ergodic, hence temporal averages are generically not appropriate for the instantaneous characterization of the climate.

Further Information
Venue:
ESI Boltzmann Lecture Hall
Associated Event:
Mathematical Aspects of Geophysical Flows (Workshop)
Organizer(s):
Adrian Constantin (U of Vienna)
George Haller (ETH Zurich)