ANKARA’DA ŞEHİR ISI ADASININ İNCELENMESİ (Detection of Urban Heat Island in Ankara, Turkey)

Abstract

Turkish Abstract: Turkiye’de hizli nufus artisi ve buna bagli olarak artan sehirlesme sicakliklarda degisimler meydana getirmektedir. Bunda ozellikle plansiz ve kacak yapilasmanin onemli bir payi vardir. Gecekondulasma sonucunda yesil alanlarin hizla yok olmasi ve hizli betonlasma sehir isi adasini (SIA) kuvvetlenmistir. Baskent oldugundan beri hizli bir sehirlesmeye sahne olan Ankara’da da SIA gelisimini, bunun alansal dagilisini ve buyuklugunu saptamak icin farkli sehir dokusunu yansitan bolgelere 7 adet istasyon kurulmus ve sicaklik olcumleri yapilmistir. Veriler degerlendirildiginde en buyuk SIA soguk donemde goruldugu icin bu calismada subat ayi incelenmistir. Oke (1979) esitligine gore Ankara’da maksimum isi adasi 9.0 °C’dir. 2 Subat 2002 saat 15:00’te bu deger 9.4 °C olmustur. Incelenen donemde gunduz zayif olan SIA aksam saatlerinde kuvvetlenerek sehir ve kirsal alanlar arasinda sicaklik farkliligi (∆T(s-k)) 7.7 °C’ye ulasmistir. Subat ayi suresince 24 aksamda SIA (∆T(s-k)≥ 1.0 °C) gorulmustur. Subat ayinda saat 21:00’da yasanan SIA’nin % 61’i 4.0 °C’nin uzerindedir. SIA goruldugu donemlerde ruzgar hizi genellikle 0.5 m sn-1’ten daha azdir. English Abstract: The rapid increase in population and corresponding rise in urbanization cause the change in temperature in Turkey. The unplanned and rapid construction has also a very big role in this process. The increase in the number of slums and rapid destruction of green areas and concretion has also strengthened urban heat island (UHI). There were seven station established in Ankara, representing the texture of the city in order to measure the temperature variation and define the development of UHI and its spatial variation. Since the biggest UHI is observed in cold period at investigation period, we investigated the month of February in this study. According to Oke (1979) equation the maximum heat island in Ankara is 9.0 °C. UHI observed 9.4°C at 15:00 on 2 February 2002. During the period of interest, UHI, which was weak during day time, strengthened in evening hours and ∆T (u-r) increased up to 7.7 °C. There were UHI (∆T (u-r)≥ 1.0 °C) in 24 evenings in February. 61% of UHIs observed at 21:00 in February was above 4.0 °C. The wind speed was less than 0.5 m s-1 during the periods of UHI.