Monitoring the spatial autocorrelation of land surface temperature with land use in different climatic regions (Case Study: The Metropolitans of Mashhad and Sari)

Abstract

Knowing the temporal and spatial changes of land use and the formation of heat islands over time is one of the most important issues in metropolitan planning and policy making. Thus, in this study heat islands and temperature changes and its relationship with land use changes have been monitored over a period of 35 years in two study areas, i.e. the cities of Mashhad and Sari, using the Google Earth Engine platform. For this purpose, the LST was computed and the land use maps of the studied periods were extracted during 8 time steps of 5 years from 1985 to 2020. The aim of this study is to investigate the spatial autocorrelation of heat islands and its relationship with land use in two studied regions with different climatic conditions. The results of temperature monitoring showed an increase in temperature between 1 to 2 °C in all types of land uses during 35 years. This increasing trend of temperature is proportional to the type of land use changes, so that the temperature increase in built-up lands was estimated to be 2 and 1.75 degrees Celsius in the cities of Sari and Mashhad, respectively. The average temperature of the three months of summer in Mashhad city in built-up areas has increased from 34.5°C to 36.25°C and in Sari city from 29.51°C to 31.51°C. while the minimum increase in temperature has occurred in the lands with forest coverage, which is 1.02 °C and 1.19 °C, respectively in the cities of Sari and Mashhad. Conclusively, in both climatic regions, the areas where the changes are in the direction of reducing or removing vegetation and creating residential areas, the temperature increase is the maximum, and the areas where the changes are in the direction of increasing forests and agricultural lands, the temperature increase is the minimum.