A systematic approach for urban heat island mitigation strategies in critical local climate zones of an Indian city

Abstract

Local climate zone (LCZ) land cover classification system has been effective in investigating the urban heat island (UHI) phenomenon. In mid-latitude tropical cities, temporal variation and composite type climate prove it difficult to evaluate critical LCZs. It is important to address which LCZ is most critical in terms of UHI and air temperature exposure and how to approach mitigation strategies for the same. The present study examines major LCZs, having greater coverage area, in the city of Nagpur, India. It uses the technique for order of preference by similarity to ideal solution (TOPSIS) to identify LCZ criticality. It selects critical local climate zone and evaluates strategies such as greening and use of reflective surfaces namely cool roof and cool pavement using ENVI met tool. Increasing green area ration is found to be a more effective strategy for the sparsely built (LCZ 9) and planned settlement with open spaces (LCZ 3F) while application of cool roof shows significant reductions in air temperature in the older unplanned settlement with dense urban agglomeration (LCZ 3). The study provides insights to planners and policymakers to resolve the “where?” and “how?” part of the UHI mitigation and management.