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| Titel |
Paleoclimate changes: a stochastic resonance model based on ice-core data analysis |
| VerfasserIn |
Tommaso Alberti, Fabio Lepreti, Antonio Vecchio, Vincenzo Carbone |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250121897
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| Publikation (Nr.) |
 EGU/EGU2016-786.pdf |
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| Zusammenfassung |
| We investigate statistical properties of paleoclimate changes during the last glacial period (i.e.
20-120 kyr BP) using an EMD based approach [1]. In particular, we showed that EDML
and NGRIP datasets are characterized by fast risings of temperature, known as
Dansgaard-Oeschger (DO) events. By applying a potential analysis, we found the existence
of two stable climate states between which the climate system oscillates during the
occurrence of DO events.
We developed two different models based on the stochastic resonance mechanism in order
to reproduce the switch between two stable climate states which characterize the
longer timescale dynamics. The first model is based on the classical concept of the
stochastic resonance in which we have a double-well potential function, describing the
internal dynamics, a periodic term, characterizing the quasi-periodic behaviour of the
system, and a noise term, describing the fast variables which are present into the
climate system. The novelty introduced in this model is related to the potential
function which is directly extracted using the EMD reconstructions obtained from the
observational paleoclimate datasets [1]. Another important novelty is obtained by
using a ”modified” stochastic resonance model in which the fast variables are not
described using a noise process but using the physical informations obtained taking into
account the EMD results on the original datasets [1]. Using these two models we note
that:
the ”classical” stochastic resonance model is able to reproduce the switchings
between the two stable states but these transitions are driven by a noise term
which is not directly related to a physical mechanism
the ”modified” model allows to consider the physical mechanism and the effects
related to the fast variables of the system such as the occurrence of DO events,
particularly evident during the last glacial period in Northern hemisphere both in
observational dataset and in simulation results
the cross-correlation coefficient between northern and southern system variables
shows a good agreement in the time-delay with respect to direct observations
when the “modified” stochastic model is taken into account
References
[1] Alberti, T., Lepreti, F., Vecchio, A., Bevacqua, E., Capparelli, V.,
and Carbone, V., Natural periodicities and Northern Hemisphere-Southern
Hemisphere connection of fast temperature changes during the last glacial period:
EPICA and NGRIP revisited,
Climate of the past, 10, 1751-1762, doi:10.5194/cp-10-1751-2014, 2014 |
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