Abstract : Rapid urbanization in tropical cities like Chennai intensifies the Urban Heat Island (UHI) phenomenon, where urban areas experience increased thermal stress and deteriorating environmental conditions. This study, through a combined empirical and simulation-based approach, examines the opportunities for applying green roofs as a multifunctional system to manage microclimate and enhance biodiversity. A comparison was made between extensive and intensive green roofs versus traditional roofs across eight different research locations, which were classified according to various local climate zones. Microclimatic parameters including air temperature, surface temperature, relative humidity, and solar radiation were monitored during the monsoon season, and field temperatures were analyzed and simulated using the Environmental Microclimate Model (ENVI-met). Results demonstrated that green roofs significantly impact microclimate by reducing air temperature by 3°C and surface temperature by over 15°C, respectively, while increasing relative humidity and thermal comfort. Intensive systems with greater vegetation density and deeper substrates achieved superior results. In the biodiversity assessment, species richness, abundance, and diversity increased significantly; the natural vegetation supports and enhances pollination and bird species in urban areas. The study demonstrates the critical significance of Local Climate Zone (LCZ) planning, sustainable materials, and climate-sensitive planning. The study's findings underscore the need to incorporate green roofing into city policies to enable climate-resilient and sustainable urban development in rapidly urbanizing tropical areas.

Keyword :Biodiversity Enhancement, Climate-Resilient Design, ENVI-met Simulation, Green Roofs, Microclimate Regulation, Urban Heat Island.