Effectiveness of heat adaptation strategies in developing cities

The development and implementation of climate action plans and adaptation strategies are crucial for addressing climate-induced disasters and crises in cities. However, the complex and heterogeneous morphological structure of large as well as medium-sized cities in developing countries which leads to micro-scale variations in urban meteorology, makes implementation of the adaptation strategies complicated and challenging. This study aims to evaluate the effectiveness of widely adopted heat adaptation strategies to mitigate the urban heat island (UHI) intensity in two Indian cities, Kolkata and Guwahati; which lie in a similar climatic regime, but differ in their built-up profiles and spatial characteristics. The WRF (Weather Research and Forecast) model, coupled with 3D urban canopy models BEP+BEM (Building Effect Parameterization/Building Energy Model), is used to evaluate variations in the meteorological profiles of both cities. Accurate representation of urban morphology is crucial to enhance the capability of mesoscale climate models like WRF to simulate urban microclimates with higher precision. Thus, finer-scale LCZs (Local Climate Zones), which capture variations in urban complexity, were derived from high-resolution satellite images using advanced machine learning techniques and integrated into the model. Three different strategies – green roofs, cool and super-cool materials, to mitigate urban heating during the hot and dry pre-monsoon season were tested by reconfiguring the model accordingly. The results demonstrated the efficiency of these adaptation measure in significantly lowering the 2m air temperature in both cities, particularly in the afternoon when UHI intensity peaks. However, performance of the different measures varied notably across the different LCZ classes and between both cities. This highlights the importance of micro-scale analysis in detecting internal variations within urban meteorological profile. This could guide especially cities with restricted resources to implement targeted mitigation measures in the different parts ensuring their effectiveness, cost-efficiency, and feasibility, for systematic urban planning.