The Urban Heat Island in an Urban Context: A Case Study of Mashhad, Iran.

Marzie Naserikia,Mojtaba Rafieian,Walter Leal Filho,Elyas Asadi Shamsabadi

doi:10.3390/ijerph16030313

Abstract

In this study, the spatio-temporal changes of urban heat island (UHI) in a mega city located in a semi-arid region and the relationships with normalized difference vegetation index (NDVI) and normalized difference built-up index (NDBI) are appraised using Landsat TM/OLI images with the help of ENVI and ArcGIS software. The results reveal that the relationships between NDBI, NDVI and land surface temperature (LST) varied by year in the study area and they are not suitable indices to study the land surface temperature in arid and semi-arid regions. The study also highlights the importance of weather conditions when appraising the relationship of these indices with land surface temperature. Overall, it can be concluded that LST in arid and steppe regions is most influenced by barren soil. As a result, built-up areas surrounded by soil or bituminous asphalt experience higher land surface temperatures compared to densely built-up areas. Therefore, apart from setting-up more green areas, an effective way to reduce the intensity of UHI in these regions is to develop the use of cool and smart pavements. The experiences from this paper may be of use to cities, many of which are struggling to adapt to a changing climate.

Highlights

Rapid urbanization has resulted in a tremendous rise in population and man-made structures of cities
The results show that the influence of the land use/land cover (LULC) on the urban heat island (UHI) intensity, which varies depending on the location’s characteristics, is undeniable
The purpose of this study is to first picture the UHI in this mega city and quantitatively assess the efficiency of the remote sensing indices related to land use and land cover patterns, namely normalized difference vegetation index (NDBI) (NDVI) and normalized difference built-up index (NDBI), in this arid region

Summary

Introduction

Rapid urbanization has resulted in a tremendous rise in population and man-made structures of cities. The population growth and constructed urban structures and surfaces have triggered many environmental problems [1]. Among climatological effects of human activities on the environment, urban heat island (UHI) is a well-documented phenomenon [2]. The UHI is a phenomenon where local air temperatures of urban environments are higher than the suburban rural areas. Changes in land use/land cover (LULC) of cities can raise the temperature of the local air and surfaces several degrees higher than the temperatures of the surrounding areas at the same time [4,5]. The interplay between human activities and the environment is known as LULC and considerably influences the urban climate [6]

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Conclusion