Impact of anthropogenic activities on urban heat islands in major cities of El-Minya Governorate, Egypt

Abstract

Urban heat islands (UHIs) represent one of the significant factors in regard to environmental and human health. UHIs are significantly changeable, responding to the land use type and the dominant anthropogenic activities. In this research, UHIs in El-Minya cities were identified based on Land Surface Temperature (LST) measurements. Thermal bands of Landsat imagery were processed to produce LST in the cities of El-Minya governorate in 2001, 2011, and 2021. In addition, the spectral indices; Normalized Difference Vegetation Index (NDVI), the Modified Normalized Difference Water Index (MNDWI), and the Normalized Difference Built-up Index (NDBI) were retrieved from the processing of multispectral Landsat imagery to assess different Land-cover units in the study area and to detect their correlation with LST/UHIs. Analysis of data indicated that LST variations are corresponding with different land-cover types. It was found that NDVI and NDWI have a strong negative influence on LST (R = −0.7 and −0.8 for both indices, respectively), while NDBI has a significant positive correlation (R = 0.85). Furthermore, the highest LST was detected at the cities of El-Minya, New-El-Minya, and Malawi, consequently. These regions have the greatest potential for UHIs formation among other El-Minya governorate cities. The year 2021 recorded the highest average LST with a value of 34.1 °C where the largest UHI area was observed in New-El-Minya (2.74Km2) in 2001, and (2.6 Km2) in 2021, as well as (1.12Km2) in El-Minya in 2011. It can be concluded that increasing LST and UHIs at different districts of El-Minya arise from urbanization and industrialization processes.