Environmental Impacts and Sustainability
Ali Sayyadi; Mohamad Javad Amiri
Abstract
One of the environmental problems today is the rising land surface temperature and the formation of heat islands in metropolitan areas, which have arisen due to the unplanned expansion of these cities. Satellite imagery is widely used in urban environmental studies to provide an integrated view and reduce ...
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One of the environmental problems today is the rising land surface temperature and the formation of heat islands in metropolitan areas, which have arisen due to the unplanned expansion of these cities. Satellite imagery is widely used in urban environmental studies to provide an integrated view and reduce costs and time. In this study, Landsat satellite imagery in TM, ETM+, and OLI sensors from 1984 to 2020, remote sensing techniques, and GIS is used to analyze the data, and SPSS software is employed to examine the correlation between the data. The results indicate that the land surface temperature in District 1 of Tehran has increased during the last 38 years. Moreover, land use in District 1 has changed significantly over this period, and urban land use increased from 16 % (1984) to 35 % (2020) while vegetation declined from 32 % to 14 %. The results of linear regression analysis show a significant correlation between satellite images and weather station data. The significance coefficient (Sig) in all stations is less than 0.05 with a 95 % confidence interval. Besides, the coefficient of variation (R) for all stations is above 80 %, and the coefficient R2 has a desirable value. The findings suggest that the trend of rising temperatures in District 1 of Tehran has become an environmental problem and the changes in land use such as declining vegetation and increasing the acceleration of urbanization are among the factors that affect it.
Environmental Impacts and Sustainability
Mohammad Javad Amiri; Ali Sayyadi
Abstract
The rising temperature of the earth's surface and the formation of heat islands in megacities have become two of the biggest environmental threats. This compound problem affects urban climatology, including urban vegetation and air pollution, human health, and the environment, including the group of ...
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The rising temperature of the earth's surface and the formation of heat islands in megacities have become two of the biggest environmental threats. This compound problem affects urban climatology, including urban vegetation and air pollution, human health, and the environment, including the group of vulnerable members of the society and public health, leading to the growing death rate. Hence, the purpose of this study is to investigate the leading causes of temperature changes and the development of a thermal island in the city of Tehran following the expansion of this metropolis in recent decades. This research uses thermal remote sensing and GIS techniques to analyze information from Landsat satellite images in (TM-ETM-TIRS) sensors from 1984 to 2020. The results of the research indicated that the surface temperature of the city of Tehran during the years 1984 to 1996, 1998 to 2008, and 2010 to 2020 experienced a relative increase in the summer and winter seasons. In the first decade, the average temperature of the green layer was -7, while the temperature of the magenta and red layers were 20 and 25 degrees, respectively. In the second decade, the average temperatures of the green and dark green classes were -1 and 3 while they were 23 and 27 degrees for the magenta and red classes, respectively. In the third decade, the average temperatures of the green and dark green classes were -1 and 3, and thost of the magenta and red layers increased to 28 and 31 degrees, respectively. Furthermore, the analysis of vegetation cover based on the NDVI index pointed to the continuing reduction of vegetation in the studied years. Regarding the direct correlation between the heat island and vegetation and the concentration of the heat island in the city center, further measures must be taken and the vegetation cover should be increased to reduce the heat island. The city center needs to be decentralized as part of the remedy via proper urban design and planning.