Study of the effects of vegetation and urban hard surfaces on microclimate and thermal comfort in Mashhad

Considering high population and hot and arid climate in most cities in Iran، creating optimum thermal comfort during the hot periods is necessary. An experiment was conducted to examine the effect of percentage vegetation and hard surfaces on changes of temperature، humidity and thermal comfort of in three urban sites and Mashhad weather station was investigated. Climate and recorded data from weather station and Danesh crossroad، Moghadam-Tabarsi intersection and Mellat Park that were different in terms of percentage vegetation and hard surfaces were compared with each other. Thermal comfort indices and the ranges of them in hottest period of 2011 were calculated by categorizing age and gender differences. The results of statistical analysis and RayMan model outputs showed that temperature and humidity of Danesh crossroad and Moghadam-Tabarsi intersection in comparison with those of weather station in particular Mellat Park were significantly higher and lower، respectively. Thermal comfort indices showed that as time passes in this period، the potential of the days create little heat stress، strong and very strong heat stresses in urban dwellers respectively and Mellat Park and weather station site were more appropriate than Danesh crossroad and Moghadam-Tabarsi intersection in terms of thermal comfort for people.