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<p>Even though many previous studies have examined the spatiotemporal variability of urban land surface temperatures (LSTs) associated urban land cover characteristics for large metropolitan cities, however, the rapidly growing small and medium sized cities in many African countries have largely been understudied. In Africa, cities of small and medium sized are expected to account and accommodate the largest urban population by 2030. This study examined the spatio-temporal variability of land cover and associated impacts on the urban surface temperature for the city of Gweru, which is a small sized city in Zimbabwe. Landsat satellite data for the year 1990, 2001, 2011, and 2021 were used for generating land cover and land surface temperature (LST). The correlations between the land surface temperature (LST) and four land cover spectral indices, the Modified Normalized Difference Water Index (MNDWI), Bare Soil Index (BSI), Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Built-up Index (NDBI) were examined in order to further analyze its impacts on the urban thermal environment of city. The findings of the study showed evidence of an expansion of built-up areas that occurred between 1990 and 2021. The expansion of the built-up areas in the city was mainly at the expense of declining bareland areas. Furthermore, the results of the study showed a general increase in the mean LST between 1990 and 2011 and a subsequent decline in 2021. The mean value of LST was 33˚C in 1990, 41.79˚C in 2001, 42.37 ˚C in 2011 and declined to 36.44˚C in 2021. The minimum values of LST indicated an increasing trend between 1990 and 2011 before it declined in 2021. In particular, the minimum value of LST was 29.65˚C in 1990, 30.21 2001, reached 35.06˚C in 2011 before it declined to 29.16˚C in 2021. However, the maximum value of LST was 39.66˚C in 1990, rose to 41.79˚C in 2001 and declined to 46.13˚C in 2011 and 43.22˚C in 2021.The study also showed that built-up areas (NDBI) and bare soil (Bare soil index) in the study area were responsible for elevating urban surface temperatures while vegetation cover (NDVI) and water (MNDWI) had significant cooling effects on urban thermal environment. The research methodology developed in this study can be used to monitor changes in land cover and land surface temperature with the aim of promoting urban sustainability and mitigating the negative and harmful impacts of extreme heat, high urban land surface temperatures and urban heat islands in cities of developing countries.</p>

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Spatiotemporal variability of urban land surface temperatures associated with land cover changes in city of Gweru, Zimbabwe

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  • 发表日期：

    2026年7月7日

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  • Pedzisai Kowe,
  • Cletah Shoko

摘要

Even though many previous studies have examined the spatiotemporal variability of urban land surface temperatures (LSTs) associated urban land cover characteristics for large metropolitan cities, however, the rapidly growing small and medium sized cities in many African countries have largely been understudied. In Africa, cities of small and medium sized are expected to account and accommodate the largest urban population by 2030. This study examined the spatio-temporal variability of land cover and associated impacts on the urban surface temperature for the city of Gweru, which is a small sized city in Zimbabwe. Landsat satellite data for the year 1990, 2001, 2011, and 2021 were used for generating land cover and land surface temperature (LST). The correlations between the land surface temperature (LST) and four land cover spectral indices, the Modified Normalized Difference Water Index (MNDWI), Bare Soil Index (BSI), Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Built-up Index (NDBI) were examined in order to further analyze its impacts on the urban thermal environment of city. The findings of the study showed evidence of an expansion of built-up areas that occurred between 1990 and 2021. The expansion of the built-up areas in the city was mainly at the expense of declining bareland areas. Furthermore, the results of the study showed a general increase in the mean LST between 1990 and 2011 and a subsequent decline in 2021. The mean value of LST was 33˚C in 1990, 41.79˚C in 2001, 42.37 ˚C in 2011 and declined to 36.44˚C in 2021. The minimum values of LST indicated an increasing trend between 1990 and 2011 before it declined in 2021. In particular, the minimum value of LST was 29.65˚C in 1990, 30.21 2001, reached 35.06˚C in 2011 before it declined to 29.16˚C in 2021. However, the maximum value of LST was 39.66˚C in 1990, rose to 41.79˚C in 2001 and declined to 46.13˚C in 2011 and 43.22˚C in 2021.The study also showed that built-up areas (NDBI) and bare soil (Bare soil index) in the study area were responsible for elevating urban surface temperatures while vegetation cover (NDVI) and water (MNDWI) had significant cooling effects on urban thermal environment. The research methodology developed in this study can be used to monitor changes in land cover and land surface temperature with the aim of promoting urban sustainability and mitigating the negative and harmful impacts of extreme heat, high urban land surface temperatures and urban heat islands in cities of developing countries.