Thirteenth International Conference on Climate Change: Impacts & Responses

Abstract

With an increasing trend towards urbanization, many studies have examined that Urban Heat Island (UHI) effect has intensified drastically and becoming even more remarkable because of the inevitable effect of heat wave. Most of the urban localities are facing extreme heat waves events, these heat waves will be intensified by the effect of urban heat island. As these events are projected to increase in both severity and frequency in the future, it is important to examine the relationship between heat waves and urban heat island intensity. To quantify the impact of the UHI during the heat wave event, this study used observations for different coastal areas. The spatial and temporal variability patterns of the urban heat island in the metropolitan city Karachi were also investigated using hourly temperature observations for a 10-year period.Data is analyzed in two phases (a) from 1998-2002 (b) from 2012-2016.During first phase (1998-2002), the maximum intensity of nighttime UHI is 1.9℃in summer. During the second phase (2012-2016) UHI has increased by 0.6℃. Although both phases were shown the similar pattern for seasonal UHI that urban–rural temperature difference was prominent in summer and this tendency was more marked at night in summer. Daytime UHI has also observed in winter throughout the study period. In heatwave period, UHI has also increased markedly.