DETERMINING THE URBAN HEAT ISLAND INDEX USING SATELLITE AND GROUND-BASED OBSERVATIONS OVER ISLAMABAD

Abstract

Urban climate is the major concern on the global level as urban heat island (UHI) is among the most emerging problems in metropolitan areas, especially, with poor air quality conditions. Greening of urbanized spaces plays a vital role in the mitigation of the UHI effect. Space borne instruments, for example, MODIS, LANDSAT, SPOT, and TRMM, are providing a constant spatial and temporal investigation of different atmospheric and land products around the globe and on daily basis. This study emphasis on the use of satellite imageries for the assessment of the change in land use, land cover, and for measurement of land surface temperature spatially and temporally for a time period of 2000-2017. In addition to the spatio-temporal variation of LST, NDVI, and TRMM, seasonal discrepancies over study area are evaluated and discussed. It can be easily distinguished that the built-up area has increased, while the water body and green spaces have been decreased gradually over the years. The year 2012 brought a significant rise in the surface and near-surface temperature in the month of June over Islamabad due to dry spell with zero rainfall. Seasonally highest LST values are observed at the end of spring and summer seasons. LST is mainly high in developed sectors especially with low vegetation areas; I-10 and I-9 and along Islamabad expressway because of increase in built-up area. The increase in average LST in Shakar-Parian and Rawal Lake areas is also due to the changes in landscape includes the destruction of trees and the development of parks, roads, and Bani Gala development. The urban heat index for Islamabad was calculated for the whole study period.