On the thermal characteristics and the mitigation potential of a medium size urban park in Athens, Greece

Measurements have been performed during summer in and around a medium size urban park located in the western part of Athens, Greece. Additional temperature data from 15 urban and suburban stations are used to perform comparative analysis at the city level. The park presents an important temperature inhomogeneity during both day and night. Average nocturnal cool island intensities against the reference urban stations varied between −0.7 K and −2.8 K, while during the daytime the average maximum cool island intensity (CII) was between −0.2 K and −2.6 K. A statistical significant correlation between the CII and the population density is found for both day and night. The park was warmer than the urban stations for ambient temperatures lower than 34 °C, while for higher urban temperatures the park was cooler and the absolute CII increased as a function of the ambient temperature. An important correlation with the wind speed is observed for wind speeds higher than 6 m/s. The mitigation potential of the park was assessed by performing three types of traverses around the park. The park cooling intensity was varying between 3.3 and 3.8 K, while the temperature gradient along the traverses changes as a function of the thermal properties of the urban areas and was between 0.2 and 1.4 K/100 m. The park cooling intensity presents a strong correlation with the wind speed for values higher than 5 m/s. The climatic influence of the park was extended up to 300 m from the borders of the park.