Assessing the Land Use Impact on Heatwave Severity in Delhi Using Urbanized Weather Research and Forecasting Model

Delhi faces significant environmental challenges, particularly heatwaves that have profound impacts on public health and sustainability. The city’s diverse urban landscape plays a crucial role in modulating heatwave intensity, yet this influence remains underexplored. Our study used the coupled Weather Research and Forecasting (WRF) urban modeling framework and incorporated detailed Local Climate Zone (LCZ) urban land categorization to simulate the near-surface thermal environment. Specifically, we configured three two-way nested domains centered over Delhi, with the innermost domain reaching 1 km resolution. The simulation was performed from May 17^th 2023 to May 28^th 2023, covering the emergence and dissipation period of the heatwave event. Key meteorological variables such as temperature, humidity, and wind patterns during the heatwave were recorded and analyzed. To provide a baseline for comparison, a parallel simulation was conducted using the standard MODIS land use classification.

As LCZ classification provides a more detailed mapping of urban development intensity compared to MODIS land use, the intra-city variability can be reflected by contrasting these model runs. We also compared the simulation results to the observational data from ground weather stations across Delhi to better quantify the spatial distribution of heatwave severity and understand the model uncertainty when simulating such extreme events. Our analysis helps identify the city blocks that have worse thermal environments and need attention for strategic actions from urban planning and public health perspectives. The findings emphasize the need for targeted mitigation and adaptation measures tailored to specific LCZs, which can help reduce the adverse effects of future heatwaves and enhance the resilience of Delhi's urban environment. Additionally, this study contributes to a broader understanding of how urbanization influences local climate extremes, offering valuable lessons for other cities facing similar challenges.