Anàlisi de les condicions meteorològiques que afavoreixen la formació de deixants de condensació

Abstract

Since the industrial revolution, human activities have modified climate and weather; the most notable example is global warming caused by the emission of greenhouse gases. The formation of condensation trails, as a result of gases resulting from combustion in jet aircraft turbines, is one of the most visible and well-known modifications. Indeed, the high density of flights at high levels of the troposphere facilitates the formation of these trails, depending on the environmental conditions, which, if they persist over time, are considered anthropogenic clouds. This work aims to study the condensation trails in the sky of Girona, from a double perspective. On the one hand, to obtain a quantification of the frequency of this phenomenon. On the other hand, to verify the conditions in the atmosphere that allow (or not) the formation of contrails. With these objectives in mind, a review of the existing literature on the conditions under which these condensation trails are produced and their effects has been carried out. An exhaustive review of the images provided by a hemispherical vision camera of the Environmental Physics Group (GFA) of the University of Girona, corresponding to 10 years (2013-2022), has also been carried out. Finally, these observations have been combined, with atmospheric conditions in the upper troposphere, given by radiosondages performed in the city of Barcelona by the Meteorological Service of Catalonia (SMC) and with information from commercial flights that passed over Girona during some days of the year 2022. The results indicate that a little more than one in four days, at some time of the day, condensation trails can be observed in the sky of Girona. It is more common in winter than in summer, and in the morning or midday than in the afternoon. On the other hand, all observations of contrails (or their absence) correspond correctly with the passage of aircraft at levels where the environmental conditions, given by the Schumann diagram, justify their formation (or non-existence)