Investigating spatial-temporal changes of climatic variables related to vegetation in urban areas: Case Study of Isfahan City.

Considering the importance of evaporation-transpiration in the hydrological cycle and its diverse applications in different sciences, calculating its value, especially the actual evaporation-transpiration, is of great importance. Considering that the abundance of vegetation is one of the most important factors influencing the temperature of the Earth's surface, this study aims to investigate the spatial autocorrelation of the Earth's surface temperature and evapotranspiration, the standardized precipitation index and the amount of albedo in relation to the vegetation in the city of Isfahan. Using data processing in the Google Earth Engine environment, a high-resolution MODIS data set was analyzed seasonally for each year during the period of 2000 to 2020. Then, evaporation and transpiration were compared and analyzed with the help of MODIS data and the Thornthwaite-Mather method, considering the calculated plant growth factor. In addition, drought prediction using the SPI index (one month, three months, six months, and twelve months) was done for the period from 2015 to 2044. After calculating the changes, a spatial analysis method (hot spots) was used in the ArcGIS software environment to identify and discover patterns and trends in the spatial data. The results of this research determined that, in the spring season, the highest percentage of NDVI does not correspond spatially with the lowest temperature, in other words, the percentage of vegetation index does not have an inverse relationship with the temperature of the Earth's surface. In the summer season, the highest percentage of the vegetation cover index is spatially compatible with the lowest temperature of the Earth's surface. In the winter season, the distribution of temperature patterns is completely different compared to other seasons due to the temperature-modulating role of vegetation using the mechanism of evaporation and transpiration.