Abstract

The unplanned and uncontrolled urbanization of Indian cities has put them under different ecological and environmental threats. Urban heat island (UHI) is one such critical ecological hazard, whereby an urban area is experiencing higher land surface temperature (LST) as compared to the surrounding rural area. In the present study, the relationship of LST and surface urban heat island (SUHI) with the degree of impervious surface (IS) and green spaces (GS) in four rapidly growing Indian cities is presented. This study utilizes different geospatial techniques, including urban-rural gradient analysis, surface urban heat island estimation using Landsat OLI/TIRS data. The results signify a strong negative correlation of LST with the IS for Ahmedabad, Jodhpur, and Nagpur, while a positive correlation is seen over Guwahati. The negative correlation is the manifestation of the cool urban islands, pertaining to higher LST over rural areas. On the other hand, Guwahati is surrounded by green vegetation, which provides natural cooling and thus lowers the LST, resulting in positive SUHI. The density of GS is found to be a significant contributor of SUHI in Guwahati city, whereas in the other three cities, its impact is insignificant due to its presence in very less amount in rural surroundings.

摘要

印度城市的无计划和不受控制的城市化进程使它们处于不同的生态和环境威胁之下。城市热岛（UHI）就是这样一种严重的生态危害，与城市周围的农村地区相比，城市地区的土地表面温度（LST）更高。在本研究中，提出了印度快速发展的四个城市中LST和地表城市热岛（SUHI）与不透水程度（IS）和绿色空间（GS）的关系。这项研究利用了不同的地理空间技术，包括城乡梯度分析，使用Landsat OLI / TIRS数据估算地表城市热岛。结果表明，艾哈迈达巴德，焦特布尔和那格浦尔的LST与IS呈极强的负相关性，而古瓦哈提地区则发现正相关。负相关关系是凉爽的城市岛屿的表现，与农村地区较高的LST有关。另一方面，古瓦哈提（Guwahati）被绿色植被包围，提供自然冷却，从而降低了LST，从而产生正SUHI。GS的密度在古瓦哈提市被认为是SUHI的重要贡献者，而在其他三个城市中，由于其在农村环境中的数量很少，因此影响不大。