Chaotic climate response to long-term solar forcing variability

Abstract

It is shown that global climate exhibits chaotic response to solar forcing variability in a vast range of timescales: from annual to multi-millennium. Unlike linear systems, where periodic forcing leads to periodic response, nonlinear chaotic response to periodic forcing can result in exponentially decaying broad-band power spectrum with decay rate Te equal to the period of the forcing. It is shown that power spectrum of a reconstructed time series of Northern Hemisphere temperature anomaly for the past 2,000 years has an exponentially decaying broad-band part with Te ≃ 11 yr, i.e. the observed decay rate Te equals the mean period of the solar activity. It is also shown that power spectrum of a reconstruction of atmospheric CO2 time fluctuations for the past 650,000 years, has an exponentially decaying broad-band part with Te ≃ 41, 000 years, i.e. the observed decay rate Te equals the period of the obliquity periodic forcing. A possibility of a chaotic solar forcing of the climate has been also discussed. These results clarify role of solar forcing variability in long-term global climate dynamics (in particular in the unsolved problem of the glaciation cycles) and help in construction of adequate dynamic models of the global climate.

Nonlinear problems of complex natural systems: Sun and climate dynamics

“…Namely, when orbiting the Galactic center the solar system and Earth are in the interarm regions the reverse of the Taylor hypothesis provides us with the outer timescale ∼ 2500 × 100 years. This time scale is larger then any known glaciation period (which are determined by the periods related to orbiting Earth around Sun, see for instance [7]). Strong turbulent fluctuations of the cosmic rays flux on such large time-scales should prevent to the glaciation cycles to occur when the solar system is in the interarm regions.…”

“…Refs. [7]). It is knowm that there is no clear correlation between the data dominated by the trends (shown in the Figs.…”

“…dT dt = −γT + (h + bh 3 ) + F cos(ωt) (7) The periodic term in this equation represents the solar forcing (η is an ambient noise, and γ, b and F are certain geophysical constants, see for more details below). The appearance of the nonlinear Duffing oscillator in the models of the global climate processes for different time-space scales: from Paleoclimate Eqs.…”

“…Basic symmetries of the systems can play a crucial role in this phenomenon (see below). For the non-linear systems far from equilibrium the oscillatory behavior can appear near bifurcation points (the dynamics generated by the Duffing oscillator can exhibit both deterministic and chaotic behavior [5]- [7], depending on the parameters range).…”

MHD dynamo in swirling turbulence: from deterministic to helical distributed chaos

“…( 1) typical for the chaotic systems, and the f c corresponds to the first dominating peak in the spectrum (see also Ref. [11]).…”