Group seminar on 12. January, 14:15 CET
Dynamical Landscape and Multistability of a Climate Model
The current astronomical configuration of Earth supports the present day Warm climate, and a globally frozen one, termed Snowball. Geological and paleomagnetic evidence suggests that during the Neoproterozoic era the Earth exhibited at least two major long lasting global glaciation periods. In this talk, using two variants of PLASIM, an intermediate complexity climate model, we investigate the associated multistability of the Earth’s climate in the macroscopic level. To induce transitions among stable climate states we introduce fluctuations in the incoming solar irradiance, allowing for an extended exploration of the state space. Viewing the state space as a dynamical landscape with valleys and mountain ridges, we infer the relative likelihood of the identified multistable climate states, and investigate the most likely transition trajectories as well as the expected transition times between them. Finally, we employ a data-driven method to automatically detect competing metastable states, enabling us to locate and study a third climate state in one of the two variants of PLASIM, resembling previously suggested exotic climatic configurations such as the slushball Earth and the Jormungand state.
Refs.
G. Margazoglou, T. Grafke, A. Laio, V. Lucarini, Dynamical Landscape and Multistability of the Earth's Climate, arXiv:2010.10374 (2020)
M. Ghil, V. Lucarini, The Physics of Climate Variability and Climate, Rev. Modern Physics, 92, 035002 (2020)
V. Lucarini, T. Bodai, Global Stability Properties of the Climate: Melancholia States, Invariant Measures, and Phase Transitions, Nonlinearity 33 R59 (2020)