User:Amending

= Contribution draft: The Urban Heat Island of Athens =

Here is a draft of my contribution about Athens, which is conceived as a paragraph for the "Urban Heat Island" article. I am still working around it, some term may be improved. The title will be "The Case of Athens, Greece".

The Urban Heat Island of Athens, Greece
"The city of Athens is characterized by a strong heat island effect, mainly caused by the accelerated industrialization and urbanization during recent years." (Giannakopoulos et al. 2010:746). The urban heat island of Athens is studied within the framework of the campaign "Thermopolis 2009" by the Democritus University of Thrace with the support of ESA and several other studies. Satellite measurements of surface temperature revealed that "In the case of Athens [...], mixed urban areas are hot spots and appear to be 3.5–4°C warmer than the surrounding rural areas, during daytime, a fact that can be attributed to intense human and industrial activities". Kassomenos and Katsoulis (2006) detect strong urban heat island affecting Athens for 1/3 of the days, switching on in the afternoon and being stronger with low humidity and clear sky conditions. Santamouris et al. (2001) by the use of 30 meteorological stations and specific measurements detect levels of urban heat island as strong as exceeding 10°C in extreme cases in central Athens during daytime and up to 5°C during the night. A daytime negative urban heat island may be detected in Athens under some synoptic conditions. The urban heat island effect in Athens is not homogeneous inside the city: it is more intense in some western parts, and less intense in green areas; it is more intense in open-surrounded positions in presence of asphalt and intense traffic circulation. The urban heat island of Athens is also variable according to the season, and winter is the period of less intense effect. According to Livada et al. (2002) some green areas that are protected by greenery such as the National Gardens inside metropolitan Athens are less or not affected by the UHI. The urban heat islands have implications also for climate change analysis. A early detection of Athens urban heat island effect over the temperatures measured by the NOA meteorological station at Thiseio was reported by Katsoulis (1987:75-76): "[...] the differences in the maximum and minimum temperature trends may be interpreted as a long-term variation due to che city's growth and the result of increasing urban temperature due to human causes". An effect of +1/+2°C on its summertime maximum temperatures due to urban heat island is reported by different studies. The warming observed in annual and summer air temperature times-series of the National Observatory of Athens weather station at Thiseio between 1970 till mid 1990s compared to reference non-urban stations "[...] must be attributed to the urban effect of Athens city as has been demonstrated by many scientists" (Repapis et al. 2007:110). The effect of the urban heat island on the maximum temperatures measured by the meteorological station of the National Observatory of Athens at Thiseio is variable across the year: it amounts about +2°C in spring and summer, less in fall, while no clear urbanization effect is detected in winter.