Individual Metropoles May Differ in Their Response to Urbanization?
Berkay Dönmez
Kutay Dönmez
Cemre Yürük Sonuç
Yurdanur Ünal
Faculty of Aeronautics and Astronautics, Department of Meteorological Engineering, Istanbul Technical University, Maslak, 34469 Istanbul, Turkey
This study examines the temperature variability over urban and rural sites of Istanbul and Ankara, two strategic metropoles in Turkiye, using multiple data sources, including satellite, ground observations, and a reanalysis product for the period of 2011-2018. The practice of this study is twi-formed. Firstly, we introduce a location-based analysis, in which we identify the differences in annual, seasonal, and monthly temperature characteristics of urban and rural stations using hourly 2-meter mean temperature provided from station observation data. Secondly, in the grid-based analysis, we utilize the GHS Settlement Model grid classification dataset with a resolution of 1 km to determine urban-rural grids and employ the MODIS-Terra daily land surface temperature data to reveal the long-term dissimilarity of the urban and rural grids. Also included in the grid-based analysis is the CHIRTS-daily temperature product at high resolution, which we use to compare the number of days where the daily maximum temperature exceeds a specified threshold at urban and rural grids in each city. Results reveal the variability of the temperature difference between the corresponding urban and rural grids, which we refer to as the urban heat island (UHI) effect. However, this variability is higher for Istanbul, where urban land use constitutes approximately 20% of the grids, compared to Ankara, where the percentage of the grids represented by urbanization is less than 4%. When we consider the urban land use in Istanbul, there is a clear signal of a shift in the location parameter of observed temperature values to the warmer side of the probability distribution function (PDF), as revealed by the kernel density estimation analysis. Yet, for Ankara, we do not see a notable change in the corresponding PDF. Long-term UHI analyses also support these, as the difference in annual, seasonal, and monthly temperature between urban and rural locations of Istanbul is more pronounced than in Ankara. This study communicates the importance of avoiding a broad generalization of the urban impact in different cities.
urban heat island, urbanization, temperature, remote sensing, land cover
- No datasets are provided.