Assessment of seasonal and spatial patterns of AOD, urban heat island and urban aerosol pollution island during change in agriculture cycles over a city region along Indo-Gangetic Plain

Abstract

Land use changes and rapid urbanization have considerably altered the Kanpur region (26°10’55.18” N – 26°38’22.71” N, 80°7’22.43” E – 80°33’30.08” E), located amidst the agriculturally intensive Indo-Gangetic Plain (IGP). Motivated by the need to understand these changes, this study hypothesizes that seasonal agricultural cycles and urban effects impact the spatial distribution of land surface temperature (LST) and aerosol optical depth (AOD) across the city and surrounding outskirt regions. Using Landsat 8 data, we examined LST, AOD, urban heat island (UHI) intensity, and urban aerosol pollution intensity (UAPI) over cultivated and harvested periods. Results show that during cultivation, the city exhibited higher LST and AOD values than the outskirts, while during harvesting, LST and AOD increased significantly in the outskirts, bringing AOD to levels similar to the city. This seasonal shift corresponded with higher UHI and UAPI intensities over the city during cultivation and over the outskirts during harvest. The results further reveal notable seasonal variations throughout the agricultural cycle, alongside spatial differences in these parameters. The observed increase in LST and AOD during the harvesting period over the outskirts is primarily attributed to land cover changes in the study region driven by agricultural practices.