Abstract Quantification and analysis of urban greenness is important in evaluating the role of urban trees in carbon sequestration and regulating land surface temperature of an urban environment. Landsat 8 satellite data was used to evaluate the effects of urban heat island based on land surface temperature (LST) in the affluent suburb of Rosebank in the north and the previously marginalized township of Soweto south of Johannesburg. It was found that the LST of Soweto was 2.58 °C hotter than Rosebank, suggesting that high-density areas with less street trees and parks are hotter than low-density suburbs. The Pearson's correlation coefficient computed between the LST and the Normalized Difference Built-up Index (NDBI) or the Normalized Difference Vegetation Index (NDVI) for the two areas, Rosebank and Soweto showed a positive correlation of 0.92 and 0.98) and a negative correlation of −0.91 and −0.99 respectively. The correlation between the NDVI and NDBI also showed negative values of −0.90 and −0.85, respectively. Based on the global bench mark for safe solar UVI, the residents of Soweto are likely to be at risk of skin and eye damage due to prolonged exposure to ultraviolet radiation than the residents of Rosebank. Thus, this study has effectively computed and evaluated the land surface temperatures of the two study areas from Landsat 8 satellite data, an information which can help potential vegetation cover programs to improve existing disparity in urban greenness in the city of Johannesburg.

中文翻译：

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利用遥感数据监测约翰内斯堡市城市环境质量

摘要 城市绿化的量化和分析对于评估城市树木在固碳和调节城市环境地表温度方面的作用具有重要意义。Landsat 8 卫星数据用于根据北部富裕的罗斯班克郊区和约翰内斯堡南部先前被边缘化的索韦托镇的地表温度 (LST) 评估城市热岛效应。结果发现，索韦托的 LST 比罗斯班克高 2.58 °C，表明街道树木和公园较少的高密度地区比低密度郊区更热。罗斯班克和索韦托两个区域的 LST 与归一化差异构建指数 (NDBI) 或归一化差异植被指数 (NDVI) 之间计算的 Pearson 相关系数显示出 0 的正相关。92 和 0.98）以及负相关分别为 -0.91 和 -0.99。NDVI 和 NDBI 之间的相关性也分别显示负值 -0.90 和 -0.85。根据安全太阳能 UVI 的全球基准，索韦托的居民可能比罗斯班克的居民因长时间暴露在紫外线辐射下而面临皮肤和眼睛损伤的风险。因此，本研究有效地计算和评估了 Landsat 8 卫星数据中两个研究区域的地表温度，该信息有助于潜在的植被覆盖计划，以改善约翰内斯堡市现有的城市绿化差异。根据安全太阳能 UVI 的全球基准，索韦托的居民可能比罗斯班克的居民因长时间暴露在紫外线辐射下而面临皮肤和眼睛损伤的风险。因此，本研究有效地计算和评估了 Landsat 8 卫星数据中两个研究区域的地表温度，该信息有助于潜在的植被覆盖计划，以改善约翰内斯堡市现有的城市绿化差异。根据安全太阳能 UVI 的全球基准，索韦托的居民可能比罗斯班克的居民因长时间暴露在紫外线辐射下而面临皮肤和眼睛损伤的风险。因此，本研究有效地计算和评估了 Landsat 8 卫星数据中两个研究区域的地表温度，该信息有助于潜在的植被覆盖计划，以改善约翰内斯堡市现有的城市绿化差异。