Urban Heat Island Effect of Large-Scale Residential Areas: A Spatiotemporal Analysis of Etimesgut District in Ankara

Abstract

Urban heat islands (UHI) disrupt the environmental balance in urban areas. The rate and impact of this formation are intensified by the increase in impervious surfaces, along with urban sprawl and land use changes. This increase reduces natural water absorption, causing heat retention and airflow restriction. Changes in land cover alter surface albedo, affecting energy interactions between the atmosphere and the surface, leading to local climate change. Remote detection methods are important tools for data gathering and assessing UHIs. This study uses a spatiotemporal analysis to examine the relationship between urban development and UHI change between 2005 and 2021, focusing on the Etimesgut district, located on the western development axis of Ankara, where land use changed from agricultural and public land to large-scale residential areas in the last three decades, in particular along with the development of mass housing by Housing Development Agency. Therefore, the district was under pressure for urban growth and mainly developed by transferring public property to private property. The analysis explains how urban sprawl increases land surface temperature (LST), contributing to the formation of UHIs. This study shows that in the Etimesgut district, where the built-up area has increased significantly between 2005 and 2021, from 9,040 ha to 12,934 ha, showing a 43.08% increase, there has been an increase in the LST by about four °C, rising from 43.33°C to 47.02°C in July. Satellite imagery-based findings indicate that the replacement of agricultural land by built-up areas accelerates the rise in temperatures in the region by weakening natural cooling mechanisms. This study intends to inform urban policy and policy development and offers an evidence-based approach using the Etimesgut district in Ankara as a case study. Urban development policies should cover climate-prone strategies and thermal governance to mitigate the UHI effects when barren or agricultural land is replaced with impervious surfaces of large-scale residential areas.