Investigation of the relationship between NDVI and EVI vegetation indices and land surface temperature in Tehran

Cities became one of the main centers for research because they are the main gathering place for human beings. One of the problems that plagues the city today, especially large cities, is the phenomenon of the city's thermal island. There are many factors involved in the spatial changes of a thermal island, including human activities and changes in land cover, which often lead to a reduction in green space. Numerous vegetation indices have been developed and in this study, NDVI and EVI indices were examined. Land surface temperature for August 18, 2021 was retrieved from Landsat images using one-channel algorithm and the above indicators for the above date were extracted. The results showed that most of the city is covered by a temperature class of 305-310 degrees Kelvin. By comparing the indices and the land surface temperature, it was found that the land surface temperature and the vegetation have an inverse relationship, so that in the south and east the temperature is lower and the vegetation is higher; but for the South and the West, the opposite is true. Also, the relationship between land surface temperature and EVI index was -23.31% and its relationship with NDVI index was about -24%; this indicates that the two indicators are similar with a slight difference.