ABSTRACT

Many factors are involved in urban heat island development, such as lack of green spaces, improper choice of building materials, densification, and other human activities. The aim of this research was to quantify the effects of land-use/land-cover (LU/LC) changes on urban land surface temperature (LST) during a 25-year period (1993–2018) for the semiarid Shiraz City in southern Iran using Landsat data (TM, ETM⁺, and OLI/TIRS) and machine learning algorithms. Five main LU/LC classes, such as orchard, vegetation, bare surface, asphalt cover, and built-up areas, were identified using a support vector machine algorithm. Landsat images were used to retrieve normalized difference vegetation index (NDVI) and normalized difference built-up index (NDBI). The results showed that the mean LST over the entire study domain increased considerably between 1993 and 2018, due to urbanization, decrease of green areas, and increasing industrial areas. Built-up areas increased considerably by 25.8% from 80 to 100.6 km² between 1993 and 2018, while vegetation cover decreased dramatically by 69.3%. Mean LST increased from 38.4 to 40.2°C during the 25-year period with a significant increase of 3.9°C between 2013 and 2018. In addition, the Urban heat island Ratio Index (URI) displayed a substantial upward trend during the 25-year period.

摘要

城市热岛发展涉及许多因素，例如缺乏绿色空间，建筑材料选择不当，致密化和其他人类活动。这项研究的目的是量化南部南部半干旱设拉子市在25年期间（1993年至2018年）土地利用/土地覆被（LU / LC）变化对城市地表温度（LST）的影响。伊朗使用Landsat数据（TM，ETM ⁺，以及OLI / TIRS）和机器学习算法。使用支持向量机算法确定了五个主要的LU / LC类，例如果园，植被，裸露表面，沥青覆盖层和建筑区域。利用Landsat图像检索归一化差异植被指数（NDVI）和归一化差异累积指数（NDBI）。结果表明，由于城市化，绿化面积减少和工业面积增加，在整个研究领域中，平均LST在1993年至2018年期间显着增加。建成区面积从80公里增加到100.6公里^2，增长了25.8％。在1993年至2018年期间，植被覆盖率急剧下降了69.3％。在25年期间，平均LST从38.4升高至40.2°C，2013年至2018年期间显着上升3.9°C。此外，城市热岛比率指数（URI）在25年期间呈大幅上升趋势期。