Spatio-temporal variation of seasonal heat islands mapping of Pakistan during 2000-2019, using day-time and night-time land surface temperatures MODIS and meteorological stations data

Urban heat islands (UHIs) create severe human health risks. Pakistan has about 220 million inhabitants, with 287 people per Km2 on average. Over the last 100 years, the maximum extreme temperature during the previous summer and winter seasons has been recorded. The forecast for the coming 50 years indicates a temperature rise in Pakistan, directly affecting physical and mental health. To address this challenge, this paper analyzes the spatial variability in Heat Islands (HI) in Pakistan from 2000 to 2019, combining MODIS satellite imagery with data from fifty meteorological stations. Different statistical and geostatistical models were applied, including geographically weighted regression (GWR), simple regression, and Geostatistical interpolation models. The results reveal the variations in nocturnal thermal on a fixed temperature of 11 degrees C, variations in frequency, and the change in day and night temperatures during summer and winter. Data fusion between MODIS and data from fifty metrological stations in Pakistan shows that spatial-temporal variation in the patterns of HI must be considered in planning processes when responding to climate change. The heat island's maximum nocturnal temperatures indicated a high rate of extension and magnitude compared to the daily recorded temperature, which implies that the overall area in the metropolitan category is covered by a temperature value of greater than 20 degrees C, raising severity to 10 degrees C in June. During June, intense night-time temperature values spread their concentration, heading towards the urban center over the Islamabad, Gilgit, Peshawar, Lahore, Quetta, and Karachi station sectors. During the day, the extension difference of the heat island was in the range of 8-10 degrees C, declining steadily from summer 2006 to summer 2015 before finally covering almost the entire metropolitan area. Higher values emerged after 2015-2019, rising in magnitude and expansion until 2019.

Automated summary

Urban heat islands in Pakistan pose severe risks to human health, with projected temperature rise due to climate change. This study used satellite imagery and meteorological data to analyze the spatial variability of heat islands in Pakistan from 2000 to 2019. The results highlight the significant variation in nocturnal temperature and the severity of heat islands in various cities across Pakistan.