Trend analysis of urban heat island intensity according to urban area change in Asian mega cities

As the urbanization progresses, the green space in the city decreases and the heat absorption surface such as concrete and asphalt pavement increases, and local urban warming occurs. As urban warming becomes stronger, the temperature difference with the suburban area appears, which is called Urban Heat Island (UHI) phenomenon. UHI is a phenomenon occurring in cities all over the world, and thus there is a possibility of causing global scale climate change. Therefore, there is an increasing need for studies on the difference in UHI intensity and long-term trends according to macroscopic characteristics related to urbanization In this study, for Asian mega cities, we conducted a correlation analysis between urban area size and UHI intensity for each Asian mega city and season during 1992-2012, and time series analysis was also performed to check the increase trends of UHI intensities. The differences according to the characteristics were compared and analyzed. Our results suggested that There is a difference in the correlation between urban area size and UHI intensity according to the season and most cities showed a significant correlation in summer, with the least correlation in winter. According to characteristics such as urban area size and economic situation of each city, there was a difference in correlation between urban area size and UHI intensity, and it seems that the influence of topography and development direction also exist. UHI intensity across the city is increased by a combination of urban area size, economic situation and population number. This is the macroscale study that analyzed the effects of urban area size and impact on UHI intensity change and based on this, future studies are required.