Thermal Conditions in C#243;rdoba City, Argentina, during 1960-2010 Period

摘要

The present work analyzes daily minimum (Tmin) and maximum (Tmax) temperature series from Córdoba Observatory weather station, which is located near the center of the city of Córdoba, Argentina, and from the Pajas Blancas and Pilar observatories, in order to have a reference counterpart of regional climate. The air temperature in Córdoba city during 1960-2010 period shows lower/higher frequency of Tmin categories lower/higher than 15°C, with respect to rural thermal conditions. Tmax categories higher/lower than 30°C, in turn, presented higher/lower frequency in the city. While the mean annual Tmin showed a significant positive trend in the entire region in the study period, Tmax presented no significant changes over time. The difference between urban and rural thermal regimes remained uniform throughout the study period, so the process of urbanization does not seem to have changed the Urban heat island status measure from Córdoba Observatory, even though the population of the metropolis has doubled. Although nocturnal thermal conditions have changed over the period, particularly in urban areas, there has been no change in the regime of extreme daytime temperatures across the region. The annual mean Tmin increase is not monotonic, but presents a significant positive partial trend until a breakpoint around 1990, and then becomes neutral or negative and loses significance. For the annual mean Tmax, the partial trend slopes are not significant in any case, so the variation of annual mean thermal amplitude is due mainly to the increase of the Tmin, probably associated with increased rainfall in the region.