Urban Heat Island and Mitigation in Tropical India

Urban heat island (UHI) studies using ground-based observations are limited in the tropical cities of India. This chapter reviews the UHI studies in the tropical cities located in the southern and central states of the subcontinent, namely Tamil Nadu, Karnataka, Kerala and Maharashtra. In tropical cities that experience high latent heat fluxes, the thermal environments are also affected by the heterogenous nature of urban settings. Majority of the UHI studies were conducted for a short period using either non-standard stations or mobile surveys, or a combination of these, with the reported UHI intensities ranging from 1.76 to 4.6 °C. Comparison between studies are difficult due to the variation in the methodology and the way results are presented. Ground-based measurements deployed in both micro and macro scales informed by high resolution remote sensing outputs will help to address the gap in the current knowledge. Dense network of stations installed using crowd sourcing approach are proven to be beneficial if uncertainties are carefully addressed. This chapter also discusses the application of UHI mitigation strategies established in similar climatic conditions and land use patterns. Mitigation actions including tree planting, use of appropriate materials as well as enhancing ventilation should be carefully chosen according to the geometry and orientation of the streets.