A researcher at the UPC's Terrassa Campus discovers a climate change pattern thanks to a new method

Dario Zappalà, a member of the Nonlinear Dynamics, Nonlinear Optics and Lasers (DONLL) research group of the Universitat Politècnica de Catalunya (UPC) on the Terrassa Campus, recently published a study in the scientific journal Earth System Dynamics revealing great anomalies in temperature variations in zones near the North Pole and the Amazon. By studying the variations in the amplitude and frequency of temperatures using a new method, Zappalà discovered a pattern.

Jul 05, 2018

As Dario Zappalà explains, “the planet’s climate is a complex system in which many elements interact with each other. In order to understand its operation and how or why the changes take place, it’s not enough to study the elements in isolation.” Following this premise, Dario Zappalà has discovered a new pattern of change that confirms, in addition to the known rise in temperature, major changes in certain regions that could seriously affect the planet’s climate balance in the near future.

The Hilbert transform and the climate
Dario Zappalà used a method that is seldom used for studying temperature, based on analysing the results after applying the Hilbert transform, an equation that has also been used to detect earthquakes and to study the behaviour of electrical and biomedical signals. “Our work provides another tool for characterising climate change, that is, another perspective from which to analyse it. The more different perspectives we have, the better we can understand what’s happening, and therefore the better we can act”, argues Zappalà.

He analysed the frequency and amplitude of temperature variations and found great changes in northern Finland and the Amazon. The data he worked with were obtained from satellites that have been monitoring temperature since 1979. According to the pattern of climate change discovered by Zappalà, in the area near the North Pole (northern Finland) the amplitude of temperature variation has decreased by around 50% since 1979, and the number of very low temperature peaks has decreased greatly during the last 10 years due to the melting of polar ice.

Zappalà also discovered that in the Amazon area the amplitude of the temperature variation has increased by 50% as a result of the drastic reduction of rainfall in this area, which is strategic for the Earth’s climate system. In the Amazon area, the temperature difference between the dry season and the rainy season has increased, with peaks of very high temperature during the last 10 years.

In addition, Zappalà has also discovered patterns of change by studying rapid fluctuations of temperature. The area where these fluctuations occur is found in the tropics and is called an intertropical convergence zone. Zappalà’s work confirms that this zone of convection is moving northwards, marking a major change in temperature dynamics since 1979. He continues, “our work confirms other studies and provides conclusive proof of major climate change. We have demonstrated with statistically significant evidence that the changes are real and systemic – they are not the result of chance. In addition, we have applied the analysis to two important databases obtained with different models applied to measurements of satellites and meteorological stations, and the results are very similar in the same sensitive areas of our planet, which also confirms their validity.”

Another member of the DONLL group, Cristina Masoller, and the researcher Marcelo Barreiro from the University of La República (Montevideo, Uruguay) also participated in this study.

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