A study of thermal controls in rapidly developing city using remotely sensed satellite data: spatiotemporal perspective

The unsusual rise in the land surface temperature is playing a vital role toward the rapid and intense changes in global climate. Occurrence of certain land use land cover and alternative changes in them is the prime cause of bringing extreme changes in temperature. In this research, using 30-year long time series (1988–2018) data from Landsat satellites for understanding relation of mean temperature with the two largest and main controlling land use classes (vegetation and built-up) in a rapidly urbanizing district, Lahore. For this purpose, multivariate statistical approaches of scatter plot and correlation coefficient were employed. Temperatures, vegetative and built-up areas were derived using a combination of different spatiotemporal tools in a specifically designed model. Critical analysis suggests breaking up of investigation timeline in two portions based on changing trend. A 23-year period from 1989 to 2011 (Temporal Window-1) and a 6-year period from 2013 to 2018 (Temporal Window-2) were tested separately for the same arguments. Vegetative area showed an increase throughout the temporal window-1 and then a rapid decrease from 2013 to 2018, while built-up area and mean temperature presented an ever-increasing trend during both temporal windows but with much higher rates in second window. Correlation of temperature with the both the investigated thermal controls has found getting strong in Temporal Window-2 showing that relation of these landcover areas with temeperature is not linear and severity is increasing with time. Moreover, temperature is found to be strongly dependent upon changes in built-up areas than that of vegetative areas. So, an increase in built-up area has much more devastating effects over the temperature rather than decrease in vegetative area. It was concluded that Lahore district is contributing in global warming more rapidly than it had ever done before.