Abstract:

Anthropogenic factors that are effective in the change of cities have negatively affected the urban climate. Urban heat islands (UHI) are formed with the increase in the temperature difference between rural and urban areas. The aim of this study is to establish the connection between urbanization and UHI. Accordingly, three regions (Istanbul Bolge, Sarıyer, Şile) from Istanbul, which is one of the places where urbanization is most intense in Turkey, were selected as samples. Meteorological data obtained from the General Directorate of Meteorology (MGM) for the selected regions from 1950 to 2021, as well as Landsat TM 5 satellite images from 1990 to 2009 and Landsat 8 satellite images from 2021, constituted the main data sets of the study. Five parameters including mean-maximum-minimum temperatures, total precipitation, and average wind speed were analyzed for the Istanbul Bolge, Sarıyer, and Şile meteorological stations. Mann-Kendall method was applied as time series analysis. An increasing trend was observed in all long-term temperature parameters of the three selected stations, starting from the first half of the 1980s. There was a decreasing trend in precipitation at Istanbul Bolge station and an increasing trend at Sarıyer and Şile stations. . A decreasing trend was observed in the wind speeds of the stations. In the years 1990-2009-2021, there was a general increase in the land surface temperature (LST) values. Especially in Istanbul Bolge, where urbanization is the most intense, the average LST of the study area is 25.5°C in 1990, 28.8°C in 2009 and 32.8°C in 2021. Sarıyer study area has an average of 23.4°C in 1990, 26.2°C in 2009 and 29.3°C in 2021. Şile study area has an average LST of 22.7°C in 1990, 23.8°C in 2009 and 26.3°C in 2021. As a result of the study, the connection between urbanization and UHI was revealed.

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