Temperature and precipitation trends in Bologna (Italy) from 1952 to 1999

An analysis was made of a historical set of meteorological data collected at the University of Bologna agrometeorological station (Cadriano, Bologna, Italy, 40°55′N, 11°4′E, 33 m a.s.l.), between 1952 and 1999. Increasing trends of approximately 0.7 °C in 48 years in the mean annual temperature were found, all the anomalies of the last 12 years being above the average. A decrease in the long-term diurnal range was also observed, due to a higher increase in the minimum than in the maximum air temperature. The annual total rainfall decreased during the period in study showing a significant negative trend in winter. The number of rainy days decreased by about 20% and the annual average water-table level receded by 27 cm during the 25 years of available data.