Surface Urban Heat Island (S-UHI) investigations using remote sensing

Abstract

Roth (2013:145) defines and differentiates urban heat island (UHI) phenomena associated with air and surface temperatures: “The Canopy-Layer UHI (CL-UHI) and the Urban-Boundary Layer UHI (UBL-UHI) refer to a warming of the urban atmosphere whereas the Surface UHI (S-UHI) refers to a warming of the surface. The S-UHI … is a surface energy balance phenomenon and involves all urban facets (street, roofs, trees, etc.). Urban surface temperatures are sensitive to the relative orientation of the surface components to the sun by day and the sky at night, as well as to their thermal (e.g., heat capacity, thermal admittance) and radiative (e.g., reflectivity or albedo) properties. It is strongest during daytime when solar heating creates large differences between dry/wet and vegetated surfaces, horizontal surfaces such as roofs and pavements (industrial-commercial zones, especially those with large, flat-topped buildings or extensive open areas of pavement e.g., airport, shopping malls, and major highway intersections). At night, some of the processes are reduced, and urban-rural differences and intra-urban variability of surface temperature are smaller than during the day”. Within this study meso-scale Urban Heat Island (UHI) assessment through remote sensing will be carried out to support the following essential urban climate research tasks: • Calculation of the surface temperature for Singapore via satellite based remote sensing data to map temporal changes of the Surface UHI (S-UHI) over the last decades. • Provision of environmental input data, products and information that shape the exposure to urban heat such as land cover, street geometry, building volume, large floor area, aspect ratio, shading, land use and land surface to be directly integrated into climate models (e.g. Cosmo, WRF). • Providing data that help to support the validation of the meso-scale canopy-layer models (e.g. SingV, WRF). • Processed output data to be incorperated into Singapore Views for visualization purposes.