Department of Geography, University of Ibadan, Ibadan, Nigeria.
Department of Geography, University of Free State Qwaqwa Campus, Phuthaditjhaba, South Africa.
Environ Monit Assess. 2020 Jan 13;192(2):109. doi: 10.1007/s10661-019-8054-3.
Rapid urbanization is having a considerable impact on various aspects of living, thereby altering the biophysical environment. This study adopted the use of remote sensing technique and geographical information system (GIS) to analyse the relationship between changing land use/land cover and land surface temperature in a rapidly urbanizing tropical city of Ibadan between 1984 and 2019. Landsat series TM, ETM+, and OLI satellite imageries of Ibadan region city for 1984, 2002, and 2019, respectively, were obtained from the US Geological Survey (USGS) Landsat series of Earth Observation satellites accessible on the Google earth engine (GEE) platform. Supervised classification was done using a random forest (RF) machine learning classifier in the GEE platform. Surface emissivity maps were obtained from the normalized difference vegetation index (NDVI) thresholds method and land cover information. The surface emissivity based on NDVI classes was used to retrieve land surface temperature (LST). The results showed an increase in urban cover from 341.72 km in 1984 to 520.58 km in 2019 with an average increase in land surface temperature from 17 °C to 38 °C, respectively. Temperature sampling in the north-south and west-east transect revealed that highly urbanized areas located at the city centre of Ibadan have the highest LST of about 38 °C. It dissipates to about 19 °C at the suburb that is less built up. A significant negative relationship exists between the health condition of vegetation (NDVI) and LST with a correlation coefficient of r = - 0.95. The study confirms the potential application of GIS and remote sensing for detecting urban growth as well as relates growth impact to LST, thereby suggesting that fitting strategies will be important for the sustainable management of the urban areas.
快速城市化正在对生活的各个方面产生重大影响,从而改变了生物物理环境。本研究采用遥感技术和地理信息系统(GIS)来分析 1984 年至 2019 年伊巴丹这一快速城市化热带城市中不断变化的土地利用/土地覆盖与地表温度之间的关系。伊巴丹地区的 Landsat 系列 TM、ETM+和 OLI 卫星图像分别来自美国地质调查局(USGS)的 Landsat 系列地球观测卫星,可在 Google earth engine(GEE)平台上获取。监督分类是在 GEE 平台上使用随机森林(RF)机器学习分类器完成的。表面发射率图是从归一化差异植被指数(NDVI)阈值方法和土地覆盖信息中获得的。基于 NDVI 类别的表面发射率用于反演地表温度(LST)。结果表明,城市覆盖面积从 1984 年的 341.72km 增加到 2019 年的 520.58km,平均地表温度从 17°C 增加到 38°C。南北和东西横断面的温度采样表明,位于伊巴丹市中心的高度城市化地区的 LST 最高,约为 38°C。在建筑较少的郊区,温度会降至约 19°C。植被(NDVI)和 LST 的健康状况之间存在显著的负相关关系,相关系数 r = -0.95。该研究证实了 GIS 和遥感在检测城市增长方面的应用潜力,并将增长的影响与 LST 联系起来,从而表明适应策略对于城市地区的可持续管理将是重要的。