Nocturnal and Diurnal Trends of Surface Urban Heat Island Intensity: A Seasonal Variability Analysis for Smart Urban Planning

Abstract

Abstract. Land management in the limited environment of city regions with immense population pressure is a challenging task. To achieve the goal of sustainable smart cities, reliable spatial information needs to be incorporated in land governance policies. In this study, Landsat 8 satellite bands were processed to derive the land use characteristics which are causing the development of urban heat islands at certain locations. To assess the prolonged effects of heat-trapping in cities, night time temperature data was obtained through in-situ data collection with error within 1 °C. Much higher intensity of urban heat island was observed during the night. The maximum increase of 1.67 °C was noted from day to night temperature for the same heat island. Seasonal analysis between winter and summer months was also carried out. The results suggested that for both day and night summer months produced more critical heat islands with maximum intensity up to 3.48 °C; while in winter the heat island intensity did not exceed 2.18 °C. Through comparative analysis between two cities with varying extent, urbanization and population pressure, it was observed that the maximum intensity of day time temperature was greater in a bigger city and heat islands were less fragmented. Heat islands covered an area of 10.39 km2 over Prayagraj and 28.29 km2 area of Kolkata. The temperature patterns obtained during day and night were statistically validated with the index of impervious surface area, at the significance level of α0.05.

Spatio-temporal dynamics of land use/cover and land surface temperature in Prayagraj city, India

“…The most prominent SUHI effect in Prayagraj was observed during the winter of 2019 and observed temperature differences ranging from 1.85°C (daytime) to 2.18°C (nighttime). 62 India’s small and medium cities face UHI-related issues due to unpredictable and uncontrolled expansion. 3,63 Urgent actions must be taken to ensure urban sustainability and residents' health.…”

“…The high LST could lead to several health problems, including heat stress and thermal discomfort, especially during the summer season, and a rise in mortality rate is reported due to high heat exposure. 62 Some major health issues related to high LST are dehydration, heatstroke and mental illness.…”

Ambient temperature modelling from surface characteristics and associating urban morphology with thermal discomfort

“…A detailed knowledge of intracity built-up patterns and associated climate characteristics is necessary for empirical problem solving. In this regard, the commonly used land cover classifications (Dutta et al, 2019;Kikon et al 2016;Rajasekar & Weng, 2009;Zhao, 2018) might not be sufficient. The Local Climate Zones (LCZs) have the potential to extract much needed local variations in a city region (Stewart & Oke, 2012).…”