UMR 5672

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Physics of Climate: How does non-linear response and chaos determine climate?

Peter Ditlevsen (Niels Bohr Institute, Copenhagen)
When Feb 06, 2017
from 11:00 AM to 12:00 PM
Where Amphi. Schrödinger
Attendees Peter Ditlevsen
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The climate of the Earth is the long term mean of the state of the atmospheric and oceanic flows and their interactions with the cryosphere (ice-masses), lithosphere (land-masses) and the biosphere. Is this long term mean at all influenced by the much shorter time and spatial scale turbulence of the underlying dynamical system? The answer to the provocative question in the title is that some indications that it does can be found in paleoclimatic records. Detailed timeseries of climatic proxies have been obtained from cores drilled in the Greenland ice-sheet. These records have a temporal resolution of about one year from present to 90 kyrs B.P. This enables us to separate, by spectral filtering, dynamics of long timescales changes (climate) and short timescales (atmosphere/ocean fluctuations). By a simple energy balance model of the Earth, it is illustrated that multiple steady states can exist, separated by bifurcation points. A detailed analysis of the climate records indicates that transitions between different steady states might be induced by the internal noise generated by the chaotic nature of the system. This applies limited predictability in the system.  

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