This research is focused on identifying urban sprawl pattern and extent in two rapidly growing major Ghanaian cities (Accra and Kumasi) and how urban expansion affected heat island effect over the period of 2002–2017 using remote sensing imagery. The research employed remotely sensed images from Landsat 7 and 8 missions for mapping the urban sprawl. Land cover classification was done by using object-based image analysis, and for land surface temperature estimation single-channel algorithm was used. The intensity and magnitude of urban heat island were estimated. The results showed that urban expansion was more dominant process than densification in both cities. A significant area of bare soils and sparsely vegetated lands became built-up accompanied by total disappearance of forest belt of Kumasi. The intensity and magnitude values indicated the presence and expansion of urban heat island in both cities. However, there was a significant amount of bare lands and sparsely vegetated areas with relatively high surface temperature in and around these cities. From the results of this work, we note that bare or sparsely vegetated land cover types in urban areas located in tropical climates can escalate overall urban temperatures. The urban heat island magnitude values were relatively higher compared to values for European cities during the heat wave of 2016. Although urban configurations and climatic conditions may be the reason for the differences, this shows how alarming and dangerous urban heat islands could be in tropical cities.

这项研究的重点是利用遥感图像确定加纳两个快速发展的主要城市（阿克拉和库马西）的城市扩张模式和程度，以及城市扩张如何影响2002-2017年期间的热岛效应。该研究采用了来自Landsat 7和Landsat 8任务的遥感图像绘制城市蔓延。土地覆被分类是通过基于对象的图像分析来完成的，对于地表温度估算，使用了单通道算法。估算了城市热岛的强度和大小。结果表明，在两个城市中，城市扩张比增密更为主导。随着库玛西森林带的完全消失，大量的裸露土地和稀疏的植被被堆积起来。强度和强度值表明两个城市都有城市热岛的存在和扩展。但是，在这些城市及其周围地区，有大量的光秃秃的土地和稀疏的植被，地表温度较高。从这项工作的结果来看，我们注意到位于热带气候的城市地区的裸露或稀疏植被覆盖的土地类型可能使总体城市温度升高。与2016年热浪期间的欧洲城市相比，城市热岛的震级值相对较高。尽管城市构造和气候条件可能是造成差异的原因，但这表明热带城市中令人震惊和危险的城市热岛可能会如此。在这些城市及其周围地区，有大量的光秃秃的土地和稀疏的植被，地表温度较高。从这项工作的结果来看，我们注意到位于热带气候的城市地区的裸露或稀疏植被覆盖的土地类型可能使总体城市温度升高。与2016年热浪期间的欧洲城市相比，城市热岛的震级值相对较高。尽管城市构造和气候条件可能是造成差异的原因，但这表明热带城市中令人震惊和危险的城市热岛可能会如此。在这些城市及其周围地区，有大量的光秃秃的土地和稀疏的植被，地表温度较高。从这项工作的结果来看，我们注意到位于热带气候的城市地区的裸露或稀疏植被覆盖的土地类型可能使总体城市温度升高。与2016年热浪期间的欧洲城市相比，城市热岛的震级值相对较高。尽管城市构造和气候条件可能是造成差异的原因，但这表明热带城市中令人震惊和危险的城市热岛可能会如此。我们注意到，热带气候下城市地区的裸露或稀疏植被覆盖的土地类型可能会使整体城市温度升高。与2016年热浪期间的欧洲城市相比，城市热岛的震级值相对较高。尽管城市构造和气候条件可能是造成差异的原因，但这表明热带城市中令人震惊和危险的城市热岛可能会如此。我们注意到，热带气候下城市地区的裸露或稀疏植被覆盖的土地类型可能会使整体城市温度升高。与2016年热浪期间的欧洲城市相比，城市热岛的震级值相对较高。尽管城市构造和气候条件可能是造成差异的原因，但这表明热带城市中令人震惊和危险的城市热岛可能会如此。