Anlysis of Spatiotemporal Behavior of Mashhad Metropolis’s Urban Heat Island

Abstract

The expansion of urbanization and the increase of population in metropolises and the growth of industrial activities of cities, It has caused changes in urban area climate. One result of these changes is the city's heat islands. The city of Mashhad has also grown rapidly in recent years. This study investigates the heat/cold island of Mashhad metropolis based on the background climate in order to identify its spatiotemporal behavior. For this purpose The MODIS Terra and Aqua land surface temperature (LST) data were obtained and the heat island was examined accordingly. A new was used to measure the heat island. In this method, Modis land use data was used to determine the urban and suburban boundaries as well as to determine the land use type of the study area. The background climate was determined based on Far-side temperature and the representative non urban area was selected based on the most frequent temperature and the heat island was calculated. Survey of heat/cold island in the daily period showed that during the day the average temperature of city is lower than non urbun temperature and at night is higher. Also the seasonal survey of heat island/could island of Mashhad metropolitan shows that daily cold island is the highest during the warm seasons and lowest in the cold seasons and the seasonal variability of nightly heat island is less than the daily cold island. The core of the daily cold island is located between the Haram and the Shahid Fehmidah Square towards the western area of Mashhad. The day time cold island matches the areas of the city with high vegetation coverage. The core of the nightly heat island is consistent with the old texture and dense area around the Haram towards the northwest of the city. The heat/cold island intensity is also directly related to the wind speed. The role of land use in intensifying or reducing the intensity of the heat island of Mashhad is well seen. In the development of the city, more attention can be paid to the use of urban land use in order to moderate the temperature of the city. © 2022, Shahid Beheshti University. All rights reserved.