On the characteristics of the summer urban heat island in Athens, Greece

Data from 25 fixed temperature stations placed in the major Athens area have been used to analyse the characteristics of the heat island phenomenon during the summer season. The city has been divided in five geographic zones presenting different thermal balances and it is found that the differences between the mean and maximum daily air temperatures, among the five areas, were statistically significant, showing that the five areas of this analysis had definitely different temperature conditions. Higher air temperatures are found in the industrial western part of the city and also the center while the lower values were presented at the northern and the eastern parts. The intensity of the phenomenon is found to be close to 5 C. Statistical methods have been developed and the mean and maximum nocturnal air temperatures as well as the number of hours where air temperature exceeds 30 °C, can be estimated using the corresponding diurnal temperature values. The overall analysis is important to identify energy and comfort problems in the city and plan in a sustainable way the rehabilitation of the zones presenting important thermal problems.