Articles | Volume 10, issue 19
Atmos. Chem. Phys., 10, 9657–9665, 2010
https://doi.org/10.5194/acp-10-9657-2010
Atmos. Chem. Phys., 10, 9657–9665, 2010
https://doi.org/10.5194/acp-10-9657-2010

  11 Oct 2010

11 Oct 2010

The complex dynamics of the seasonal component of USA's surface temperature

A. Vecchio1,2, V. Capparelli2, and V. Carbone2,3 A. Vecchio et al.
  • 1Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), unità di ricerca di Cosenza, Ponte P. Bucci cubo 31C, 87036 Rende (CS), Italy
  • 2Dipartimento di Fisica, Università della Calabria, Italy
  • 3Liquid Crystal Laboratory, IPCF/CNR, Italy

Abstract. The dynamics of the climate system has been investigated by analyzing the complex seasonal oscillation of monthly averaged temperatures recorded at 1167 stations covering the whole USA. We found the presence of an orbit-climate relationship on time scales remarkably shorter than the Milankovitch period {related to the nutational forcing}. The relationship manifests itself through occasional destabilization of the phase of the seasonal component due to the local changing of balance between direct insolation and the net energy received by the Earth. Quite surprisingly, we found that the local intermittent dynamics is modulated by a periodic component of about 18.6 yr due to the nutation of the Earth, which represents the main modulation of the Earth's precession. The global effect in the last century results in a cumulative phase-shift of about 1.74 days towards earlier seasons, in agreement with the phase shift expected from the Earth's precession. The climate dynamics of the seasonal cycle can be described through a nonlinear circle-map, indicating that the destabilization process can be associated to intermittent transitions from quasi-periodicity to chaos.

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