Analysis of the Relationship Between Earth Surface Temperature and Vegetation in the Formation of Heat Island and its hazards (Case Study: Isfahan Metropolis)

Urban expansion leads to the creation of urban heat islands, which can create risks for human health and the environment. Knowledge of the state of vegetation, changes in land use and temperature of each region over time is very important and is used in micro and macro planning. Therefore, the purpose of this research is to investigate the relationship between temperature and vegetation in creating a thermal island in Isfahan city. In this regard, the use of Landsat ETM satellite images during the period of 1990-2019, LST and NDVI indices, and land use were studied and investigated. The results of the investigations show an increase in the size of the city and a decrease in the size of garden lands and marginal pastures of the city. Areas without vegetation are located in the urban area and residential areas and in the southern and eastern heights of Isfahan city. The maximum NDVI index is also in the western and southeastern areas of Isfahan city. The intensity of heat islands is more than other land uses according to the minimum and maximum level and average temperature in urban land and with the increase in the area of ​​residential uses and urban development, the intensity of heat islands has increased. On the other hand, the lowest temperature intensity of heat islands is observed in irrigated agricultural lands and gardens. In general, it can be said that in the city of Isfahan, the high temperature is mostly in the central core of the city, and the surroundings of the city are covered by the middle temperature layer. Low temperatures have also been observed in agricultural use. Parks and urban green spaces also have medium temperature classes due to their proximity to urban uses and being influenced by them. During the studied period, the largest area was related to average temperature and this trend will continue in the coming years.