Department of GIS, The Graduate School of Natural and Applied Sciences, Dokuz Eylul University, Izmir, Turkey.
Department of Environmental Engineering, Faculty of Engineering, Dokuz Eylul University, Izmir, Turkey.
Environ Monit Assess. 2020 May 20;192(6):386. doi: 10.1007/s10661-020-08322-1.
A surface urban heat island (SUHI) is a significant meteorological phenomenon of the microclimate and environment in urban territories. Knowledge about the variations of SUHI is critical for urban planning and public welfare. In the current study, the seasonal and spatial changes of the Istanbul SUHI and its interactions with spectral indicators of the urban heat phenomenon including the normalized difference vegetation index (NDVI), tasseled cap wetness (TCW), and surface albedo were analyzed. The National Aeronautics and Space Administration (NASA) L2 thermal products (brightness temperature) of Landsat 8 imageries were used to calculate land surface temperature (LST) values. The thermal islands of the study area were detected based on the Urban Thermal Field Variation Index method. The retrieved LST values showed acceptable agreement with in situ observations of mean daily temperature for all the seasons. Monthly precipitation, however, demonstrated good correlation with summer and autumn LSTs. It is found that the central parts of the metropolitan area were subject to the most intense SUHI in the spring and summer seasons. Outskirt areas showed higher thermal values during cooler seasons of autumn and winter. The results of spatio-temporal interactions of SUHI and the spectral indicators revealed a negative correlation for NDVI and TCW and a positive correlation for surface albedo during different seasons from summer 2017 to spring 2018. The highest and lowest correlations were found between SUHI and TCW (spring) and surface albedo (winter), respectively. The regression results overall suggested that TCW and NDVI were the best indicators of SUHI in Istanbul. Surface albedo was not recommended for seasonal monitoring practices of SUHI in the study area due to the high differences in its seasonal interactions.
城市表面热岛（SUHI）是城市地域微气候和环境的重要气象现象。了解 SUHI 的变化对于城市规划和公共福利至关重要。本研究分析了伊斯坦布尔 SUHI 的季节性和空间变化及其与城市热现象的光谱指标（归一化差异植被指数（NDVI）、缨帽湿度（TCW）和地表反照率）的相互作用。使用美国国家航空航天局（NASA）L2 热产品（亮度温度）对 Landsat 8 成像仪进行计算，得到地表温度（LST）值。基于城市热场变化指数法检测研究区域的热岛。检索的 LST 值与所有季节的平均日温度的实地观测值具有良好的一致性。然而，每月的降水与夏季和秋季的 LST 具有良好的相关性。结果表明，在春季和夏季，大都市中心地区受到最强烈的 SUHI 的影响。在较凉爽的秋季和冬季，郊区地区的热值较高。SUHI 与光谱指标的时空相互作用结果表明，2017 年夏季至 2018 年春季，NDVI 和 TCW 呈负相关，地表反照率呈正相关。SUHI 与 TCW（春季）和地表反照率（冬季）之间的相关性最高和最低。总体而言，回归结果表明，在伊斯坦布尔，TCW 和 NDVI 是 SUHI 的最佳指标。由于其季节性相互作用存在较大差异，不建议将地表反照率用于该研究区域 SUHI 的季节性监测实践。
