Evaluating the Effects of Urban Green Space on the Formation and Development of Heat Island Phenomenon (Case Study of Arak)1

One of the important concerns is a steady rise of temperature in the urban areaswhich is referred to as “urban heat island phenomenon”. The green space is a vital part of morphological structure of cities and the main cause of ecological balance. It creates active natural ecosystems in urban areas and plays the major role in increasing the sustainability and livability of cities. Considering various effects of the green space on the formation and persistence of heat island phenomenon in the urban fabric surface, the present case study aimed at investigating the structure forming such surface in Arak. In this study, environmental thermometers were applied for examining the temperature
changes. To analyze the urban structure and the distribution of green space in the fabric surface of Arak metropolis, remote measurement techniques or the assisting spectrums within the visible range of IKONOS satellite images were used. By entering the collected data into the Geographic Information Systems, the environmental thermal models were developed and the formation of the heat island phenomenon in Arak and the impact of different green space structures on this phenomenon were explored. The results indicated that the vegetated areas, mainly the green spaces with a continuous structure, suitable extent, and appropriate distribution,change the morphology of the heat island phenomenon due to the impact of thermal balance. The dry and impermeable urban
surfaces, however, leave the greatest heating impact by absorbing radiant energy. Considering the findings, it can be concluded that the continuous monitoring of the impact of heat island effect in Arak and the management of the urban structures, especially studying plant typology, histology, and morphology in the construction of green spaces, appear essential. These actions not only reduce the urban management expenses, but also prevent the intensification of theundesirable effects of the environmental consequences within the fabric structure of the city.