Investigation of urban heat islands of Tabriz metropolis using multi-time data of LANDSAT8 satellite based on hot spot analysis method

Rapid urbanization in Tabriz has a significant impact on the urban thermal environment and these changes have affected the climate, environment and quality of life of residents. The aim of this study was to evaluate the urban heat islands (UHI) of Tabriz using spatial autocorrelation methods and its relationship with physical parameters of the surface. NDVI and Split Window algorithms based on TIRS and OLI Sensor of Landsat 8 satellites were used to calculate the vegetation index and land surface temperature; then the relationship between LULC, NDVI and Land Surface Temperature (LST) changes evaluated. Spatial autocorrelation methods Moran's I and Hot Spot were used to identify UHI. The results showed that in the metropolis of Tabriz, there is a significant inverse relationship between α = 0.05 between LST and NDVI. LST minimum and maximum 11.99 to 58.49 Celsius respectively in central and north-west of the city is obtained. Also, the assessment of land surface temperature with LULC has shown that the impervious surface along with the worn-out urban textures are the most important reasons for the intensification of Tabriz urban heat islands. The Moran's I space spatial autocorrelation method showed that the LST of Tabriz has a spatial structure or in other words has a cluster pattern and its value varies between 0.92 and 0.95. The urban heatislands of Tabriz are of the peripheral and triangular type, which increase the intensity and extent of urban heatislands from the center. The largest identified heatisland is located in District 6 of the city. Due to the existence of Tabriz Airport, as well as the existence of barren lands and worn-out urban textures, this area has the maximum land surface temperature (LST).