Urban Heat Islands (UHI) are urban areas that experience higher temperatures than surrounding rural areas due to human activities. This is caused by the replacement of natural cover with heat-retaining materials in construction, and increased heat emissions in urban areas. UHI can raise temperatures by 1°C in smaller cities and up to 12°C in large metropolitans. The increased temperature can cause a variety of problems:
a. Increased human mortality: Prolonged exposure to high temperatures and humidity levels can cause human bodies to overheat and suffer multiple organ failures. UHI and global warming combined can make sustained wet bulb temperatures of 35°C possible, putting entire cities at risk of heatwaves.
b. Compromised health and comfort: UHI contributes to higher daytime temperatures, reduced night-time cooling, and higher air-pollution levels. This can lead to heat-related deaths, illnesses, and general discomfort, as well as exacerbating naturally occurring heatwaves.
c. Increased energy consumption and emissions: UHI leads to higher demand for indoor cooling, which increases energy consumption and the use of fossil-fuel power plants. This results in higher emissions of air pollutants and greenhouse gases, causing harm to human health and contributing to climate change.
The following research activities are being undertaken at the Center to understand and tackle the effects of Urban Heat Island:
· Visualizing the Impact of Urban Heat Islands (UHI): District level simulations play a crucial role in assessing the impact of UHI on urban areas. By comparing temperatures in cities with surrounding rural areas, these simulations provide insights into the effects of human activities on urban temperatures. Data collected from actual temperature measurements and satellite weather data is utilized in these simulations. The findings from these simulations help identify specific research problems and formulate targeted solutions.
· Microclimate Studies: Physical simulations of heat entrapment, pollution dispersion, and other relevant phenomena are conducted in a microclimate laboratory. These simulations help study the impact of UHI on varying scales.
· Mitigating the Effects of UHI: Efforts are being made to develop and analyze solutions to mitigate the impacts of UHI. Strategies include implementing cool roofs, passive design modifications to reduce energy consumption in buildings, town planning to minimize UHI effects in large cities, vertical gardening, and identifying the best materials for building envelopes and pavements, such as retroreflectors.