Estimation of Air Temperatures for the Urban Agglomeration of Athens with the Use of Satellite Data

The thermal environment is a significant part of the urban environment; it is a reflection of the surface and atmosphere energy balance as well as of the energy fluxes between the surface and the atmosphere close to the surface. Elevated temperatures in urban areas enhance photochemical pollution and increase the energy needs for cooling. In addition, a well-documented phenomenon in cities is the urban heat island (UHI), which refers to higher LST and air temperatures (Tair) in the city as compared to the rural surroundings . For Athens a mean intensity of 5.6˚C has been reported for the surface urban heat island (SUHI) during summer months using satellite remote sensing, while a summer daytime UHI amplitude growing rate of 0.8˚C per decade has also been found.

The much higher sensible heat flux values compared to latent heat flux expected in Athens have been validated in energy budget experiments. LST has been found to be up to 5˚C lower than Tair during summer nights and up to 15˚C higher during the rest of the day. Weather prediction models have recently also been used in order to simulate the thermal environment of Athens . Studies attempting to assess the effect of local scale and mesoscale phenomena on the UHI of the area have reported that both sea breeze and anticyclonic conditions tend to reduce the UHI intensity.Read more.....