Variability of temperature and its impact on reference evapotranspiration: The test case of the Apulia Region (Southern Italy)

The present study provides an assessment of the climate variability at a subnational scale, focusing on the case of the Apulia region, in Southeastern Italy. The variables considered for the purpose of a trend analysis were the minimum, maximum, and mean temperatures, and reference evapotranspiration. These are very important in an urban-rural planning context. The study was based on 38 monitoring stations and consisted in the application of the nonparametric Mann-Kendall test and a progressive trend analysis, both used to detect the changes. The 1950-2003 period was investigated on seasonal and annual scales. The results generally showed a warming process and an acceleration of the atmospheric evaporative demand which took place especially since the mid-1970s. The latter had a significant positive trend, while the period before the break point of the 70s had a cooling effect. Finally, the warming effect was more pronounced for minimum temperatures.