Climatic effects of urbanization in istanbul: a statistical and modeling analysis

Abstract

Abstract:Statistical and numerical modeling tools were used to investigate the climatic effects of urbanization in Istanbul, the largest city in Turkey. Mann-Kendall trend test was applied to minimum temperature data from stations located in urban, suburban and rural areas in Istanbul to determine the existence and significance of trends, and the approximate years in which changes in the trends started. In addition, using a mesoscale atmospheric model, a sensitivity experiment was carried out to explore the atmospheric effects of urbanization in the city. Both statistical and modeling analyses indicated significant warming in the atmosphere over the urbanized areas. Mann-Kendall tests indicated statistically significant positive trends in the time series of the differences in minimum temperatures between urban and rural stations. Seasonal analyses showed that the urbanization effect on climate was most pronounced in summer. In most cases, the changes in the trends occurred in the 1970s and 1980s when the population growth rate in Istanbul increased dramatically. The model results exhibited a significant expansion of the urban heat island in Istanbul from 1951 to 2004, fairly consistent with the expansion of the city in this period. A two-cell structure for the urban heat island emerged at the reference level from the difference of the July simulations with current and past landscapes: one on the European side and the other on the Asian side of the city. The maximum reference-level temperature difference between the past and present simulations was found to be around 1°C. The modeling experiment also indicated that the velocity of the prevailing northeasterly wind and the water vapor mixing ratio were both reduced over the city. The heating effect due to urbanization was found to penetrate about 600-800 m height in the atmosphere over the city, and the two surface heat island cells were found to combine aloft.

Spatio-Temporal Trends of Urban Heat Island and Surface Temperature in Izmir, Turkey

“…For instance Ezber et al [10] used statistical and numerical modeling tools to investigate the climatic effects of urbanization in Istanbul using the data from 6 meteorological stations and found a significant warming trend in the atmosphere over the urbanized areas. Likewise, Çiçek and Doğan [11] investigated the effects of urbanization on temperature variation in Ankara using the data from 7 meteorological stations and concluded that there has been a significant increase with the UHI intensity in winters.…”

Impacts of land cover data quality on regional climate simulations

“…The impacts of land cover change on warm season climate over different spatial and temporal scales have been studied by Pielke et al (1999Pielke et al ( , 2001Pielke et al ( , 2007, Weaver and Avissar (2001), Pitman et al (2003) and Ezber et al (2007). For example, Pielke et al (1999) investigated the possible impacts of twentieth century land cover change on Florida peninsula's near-surface temperature and convective rainfall for July-August.…”

The implications of geography and climate on drought trend

“…Therefore, the Mann-Kendall test can be applied for trend analysis using monthly and seasonal climatic data (Kadıoglu and Aslan, 2000) and has been used in research on precipitation changes with respect to geographical factors, differentiated by season (Sinoga et al, 2011 Ezber et al (2007), Mourato et al (2010), Caloiero et al (2011), andMitra et al (2012). Mann-Kendall statistic S is computed as follows (Burn, 1994;Westmacott and Burn, 1997):…”