A Study of Canopy Urban Heat Island of Baghdad, Iraq

Based on different two sets of data such as Landsat satellite imageries and daily air temperatures at 2 m high, canopy urban heat island (CUHI) phenomenon was investigated over Baghdad city for time span of three years: 2008, 2013 and 2019. The detection of changes in built-up areas was carried out to extract built-up index using ArcGIS 10.4.1 software with an overall accuracy of 94%. The results show that the built-up areas in the surface of the city have been increased from 621.7 km2 in 2008 to 727.3 km2 in 2019. This increase with high population density produced adverse thermal effects on atmospheric environment represented by CUHI. This was verified by analyzing daily, season and annual means of air temperature at the same years above measured at two different places: 1) urban site located at city center (Mustansiriyah University) and 2) rural site at the countryside of the city (International Baghdad Airport). Using the difference in daily temperatures between the two sites, the intensity of CUHI is computed. The results showed that the maximum daily CUHI is found in summer month (July) in 2019 with value 3.4°C, while the annual means are ranged from 1.5 (in both 2008 and 2013) to 2.4°C (in 2019). Finally, CUHI intensity is related with population density and built-up index in nonlinear variation.