Evolution of urbanization and its impact on temperature trends of Quetta city in Pakistan

Abstract

Quetta is an important economic, historical and culturally a rich city located in the south-west of Pakistan. Like many other cities of the world, Quetta faced massive urbanization during last three decades. It has 1.1 million populations. The consequences of rapid urbanization in Quetta city are significant through changing urban area's temperatures than its nearby regional areas as a result of alteration of natural land cover change into built-surfaces at city scale. In this context, the objective of this study is to explore the effect of urbanization on variability of minimum (dTn) and maximum (dTx) temperature trends of Quetta city by comparing with nonurban regional stations. For this purpose, first the evolution of urbanization during 1980s to 2013 was analysed by using satellite image processing techniques for the years 1989, 2000 and 2013. To study the impact of urbanization on dTn and dTx of Quetta city, the time series data of daily average monthly minimum (Tn) and maximum (Tx) temperatures ranging from 1947 to 2013 of Quetta city and the seven regional stations were analysed by using linear regression. The results show that during last twenty years, urban population and urban surface area increased to 80% and 194%, respectively. The variation in annual and seasonal temperature trends depicted that Tn and Tx at Quetta city are increasing more than the regional stations and Tn increased faster than Tx at urban and regional scale except winter season.