Trend analysis development of urban heat island using thermal remote sensing

Document Type : Original Article


1 Department of Environmental Science, Yazd University, Yazd, Iran,

2 Department of Environmental Science, Yazd University, Yazd, Iran

3 Department of Natural Resources, Isfahan University of Technology, Isfahan


Population growth and urbanization development are the major factors in increasing land surface temperature (LST) in urban areas which lead to urban heat Island (UHI). Green covers play an important role in improving the comfort level of citizens and achieving sustainable urban environment through decreasing temperature, increasing humidity and finally dwindling UHI. The current study aims to analyze and evaluate the changes of green covers and LST in Isfahan Metropolitan Area (IMA), Iran, from 1998 to 2014. This study emphasizes on the impact of green covers on IMA temperature pattern. Accordingly, Normalized Difference Vegetation Index (NDVI) threshold method was applied to obtain the land surface emissivity (LSE). In addition, Planck’s law for TM image and Split Window (SW) algorithm for OLI/TIRS image were utilized in order to retrieve LST. It was validated with data collected from 5 stations within the city. Temporal and spatial changes in IMA’s LST were then analyzed using statistical methods, Mann-Kendall analysis and Urban-Heat-Island Ration Index (URI). The result indicates that LST in IMA had an increasing trend over the study period and its intensity, generally, concentrated in the northwest and the northeast of the city, the bed of dried Zayandeh-Rood and green covers along the river bank which destroyed. Also, there was an increasing trend in URI from 0.25 in 1998 to 0.312 in 2014. All in all, it can be concluded Mann-Kendall trend test and URI were appropriate outfits to analyze satellite images in order to identify the spatio-temporal change of UHI.