Uhi Effect

The Urban Heat Island (UHI) effect is an increase in temperatures in a city or town when compared with the surrounding rural areas. The concept was first investigated by Luke Howard in London at the start of the 19th century. The largest UHI intensities (difference in temperatures) occur at night; this combined with the phenomenon of Global Warming can cause serious health problems during periods of sustained heat because there is no relief in urban areas. In extreme cases this can lead to fainting, heat stroke and even death, therefore is important for building designers to be able to mitigate the effects. Some current mitigation methods in practice are cool roofing, cool paving and landscaping. These methods are doubly effective as they help human health and reduce the energy cost for cooling buildings, however before mitigation can be implemented the UHI intensities need to be predicted (Gartland, 2008).The canyon model can be used to predicted the UHI effect; the model works on the concept that long wave radiation is trapped by the urban canyon shape (tall buildings surrounding pavement) thus increasing the temperature. The rural environment is unhindered and the energy can escape thus cooling occurs; the difference in these temperatures is defined as the UHI intensity (Cheung, 2011). This dissertation will construct small scale canyons to improve the accuracy of the model. As a contingency previously collected data may be used to try and predict UHI intensities if there are complications with developing the canyons.