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Earth System Dynamics An interactive open-access journal of the European Geosciences Union
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Volume 9, issue 2 | Copyright
Earth Syst. Dynam., 9, 383-391, 2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 18 Apr 2018

Research article | 18 Apr 2018

Quantifying changes in spatial patterns of surface air temperature dynamics over several decades

Dario A. Zappalà1, Marcelo Barreiro2, and Cristina Masoller1 Dario A. Zappalà et al.
  • 1Departament de Física, Universitat Politècnica de Catalunya, Rambla St. Nebridi 22, Terrassa, 08222 Barcelona, Spain
  • 2Departamento de Ciencias de la Atmósfera, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay

Abstract. We study daily surface air temperature (SAT) reanalysis in a grid over the Earth's surface to identify and quantify changes in SAT dynamics during the period 1979–2016. By analysing the Hilbert amplitude and frequency we identify the regions where relative variations are most pronounced (larger than ±50% for the amplitude and ±100% for the frequency). Amplitude variations are interpreted as due to changes in precipitation or ice melting, while frequency variations are interpreted as due to a northward shift of the inter-tropical convergence zone (ITCZ) and to a widening of the rainfall band in the western Pacific Ocean. The ITCZ is the ascending branch of the Hadley cell, and thus by affecting the tropical atmospheric circulation, ITCZ migration has far-reaching climatic consequences. As the methodology proposed here can be applied to many other geophysical time series, our work will stimulate new research that will advance the understanding of climate change impacts.

Publications Copernicus
Short summary
The dynamics of our climate involves multiple timescales, and while a lot of work has been devoted to quantifying variations in time-averaged variables or variations in their seasonal cycles, variations in daily variability that occur over several decades still remain poorly understood. Here we analyse daily surface air temperature and demonstrate that inter-decadal changes can be precisely identified and quantified with the Hilbert analysis tool.
The dynamics of our climate involves multiple timescales, and while a lot of work has been...