Investigating the effect of environmental and demographic parameters on the spatial distribution of Tehran's metropolis surface temperature by combining statistical models and Mono-Window model

Introduction One of the emerging environmental hazards arising from the expansion of urbanization is the phenomenon of urban heat island. Urban heat island is a phenomenon in which urban areas experience warmer temperatures than the surrounding countryside. This phenomenon has been studied and recorded in the world over 150 years ago and generally, along with natural vegetation changes, appear to impenetrable surfaces such as pavement streets, cement, asphalt, concrete, etc. The effects of urban heat island on human life include increased energy consumption due to increased demand for building cooling during the warm seasons, increased heat stress and reduced staffing efficiency, increased water consumption and increased urban air pollution. Also, UHI has caused a change in the urban and global climate and given the increase in population, the importance of energy and the issue of global warming will increase over the coming decades. The city of Tehran is the capital and center of economic activity in the country. Each year, a large number of different provinces migrate to the province to work, which will destroy the green space and increase population in the city, which causes a lot of problems, including increasing the surface temperature. Therefore, the aim of this paper is to investigate the effect of demographic and environmental parameters on the spatial distribution of Tehran's metropolis surface temperature. Materials and methods In this study, the Landsat 5 satellite image of TM sensor for the studied area has been used. In order to complete input parameters for mapping surface temperature using satellite imagery of meteorological data, and for providing field samples, Google Earth images and topographic maps prepared by the survey organization, were used to provide surface weather maps. At first, the preprocessing steps were applied to prepare images including atmospheric correction. Then, the images were classified using a Maximum Likelihood and were classified into four landuse, built up, fallow, water and green space. After classification, each of the images was categorized using precision classification controls. In the next step, using the Mono Window algorithm, surface temperature was obtained for each image. Results and discussion Regarding existing landuses, the area was classified by 4 types of built-up, green space, bare land, water, using the supervised classification method. The area built-up, green space, bare land and water are 37061.46, 9512.91, 11470.05 and 44.91 ha, respectively. The most area of landuse is built-up. The surface temperature varies from 294 to 328 degrees Kelvin. The lowest average temperature is for water use and natural areas such as green spaces, forest and urban parks, while the maximum temperatures are in shallow land and impenetrable lands such as asphalt, street paving and other Man-made coatings, as well as industrial and commercial land, residential and transportation applications. Based on the total population of Tehran in 2011, the 21, 22, 12 and 9 regions of the main core of the urban heat island are among the low population areas of Tehran. Due to various landuses (industrial, commercial, transportation, etc.), low population density in these areas appears natural. While the urban heat island in these areas is due to industrial activities, airports, transportation, commercial land use, and bare land degradation. Map of surface temperature and population distribution in different regions of Tehran show that regions with high temperatures in areas 4, 5, 15, 2 and 14, which have a high population density in them, have been created. Although these areas are not among the main heat island in Tehran; however, due to high population density, high traffic volume, transport pollution from these areas is endangered by the emergence and expansion of urban heat islands. Conclusion The purpose of this research is to investigate the effect of demographic and environmental parameters on the spatial distribution of Tehran's surface temperature. The results of the study indicate that heterogeneous spatial distribution factors of surface temperature in Tehran are different. These factors are deliberately due to different land use and vegetation in the region. In the northern regions of Tehran, an uncompromising urban structure along with green space has caused these areas to have a low surface temperature, while the high part of the central part of the city with high building density and poor green space is high. Finally, the results of the relationship between surface temperature and population distribution in different regions of Tehran show that regions with high temperatures in areas 4, 5, 15, 2 and 14, which have a high population density in them, are created.