Abstract
A three-dimensional, non-hydrostatic, high-resolution numerical model was used toanalyse urban heat-island (UHI) intensity in an idealised but realistic configuration.The urban area was 20 km square and lay on flat land at about latitude 50° Nin a maritime climate. In the model the urban area was represented by anomalies ofalbedo, anthropogenic heat flux, emissivity, roughness length, sky-view factor (SVF),surface resistance to evaporation (SRE) and thermal inertia. A control simulationincluded all these factors and the resultant UHI structure, energetics and intensitywere validated against observations. The results also compared favourably withearlier simulations. A series of experiments was conducted in which successively one of the anomaliesthat represented the urban area was omitted from the control simulation so as toprovide the basis for an assessment of its effect. In daytime the individual effectsdue to albedo, anthropogenic heat, emissivity, SVF and thermal inertia ranged from0.2 to 0.8 °C. In common with albedo, anthropogenic heat, emissivity andSVF, the SRE aided the formation of a UHI; it was also the most important factorin increasing its intensity. The roughness length had the opposite effect. At nightemissivity, roughness length, SVF and SRE had effects ranging from 0.3 to0.75 °C, but the largest effect (2 °C) was due to the anthropogenicheat. These results showed a difference in the causes of daytime and nighttime UHIs.In daytime the roughness length and SRE were the most important factors affectingUHI intensity; at night the anthropogenic heat was the most important. The simulationssuggested that the size of the urban area had a minimal effect on UHI intensity.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.