Urban Climates

Abstract

Urban Climates is the first full synthesis of modern scientific and applied research on urban climates. The book begins with an outline of what constitutes an urban ecosystem. It develops a comprehensive terminology for the subject using scale and surface classification as key constructs. It explains the physical principles governing the creation of distinct urban climates, such as airflow around buildings, the heat island, precipitation modification and air pollution, and it then illustrates how this knowledge can be applied to moderate the undesirable consequences of urban development and help create more sustainable and resilient cities. With urban climate science now a fully-fledged field, this timely book fulfills the need to bring together the disparate parts of climate research on cities into a coherent framework. It is an ideal resource for students and researchers in fields such as climatology, urban hydrology, air quality, environmental engineering and urban design.

Summertime surface energy balance fluxes at two Beijing sites

“…Incoming longwave radiation L ↓ is primarily influenced by the existence of cloud, boundary layer temperatures, water vapour and aerosol content (Flerchinger et al, ; Wang and Dickinson, ; Oke et al, ). As expected (e.g., Kotthaus and Grimmond, ; Ao et al, ), cloud cover enhances L ↓ at the two sites (Figure e,f).…”

High‐Resolution, Multilayer Modeling of Singapore's Urban Climate Incorporating Local Climate Zones

“…The urban energy balance is defined as where Q * is the net all‐wave radiation, Q H and Q E are the turbulent sensible and latent heat fluxes, respectively, ∆Q s is the net storage flux, and Q F is the AH flux. Here the net heat advection is assumed to be negligible (Oke et al, ).…”

“…One such phenomenon at the mesoscale is the urban heat island (UHI) effect, that is, the increase of subsurface, surface, or air temperatures observed in an urban environment compared to the undeveloped rural surroundings (Chow & Roth, ). Here the focus will be on the canopy‐layer UHI, which is defined as the difference between the air temperature contained in the urban canopy layer (UCL), the layer between the urban surface and roof level (the exterior UCL), and the corresponding temperature in the near‐surface layer of the countryside (Oke et al, ). UHI is generated primarily from reduced wind speed due to urban roughness, nighttime long wave radiation trapping, building material thermal properties, the lack of vegetation and the anthropogenic heat (AH) released due to human activities, including waste heat from automobiles, air conditioning, industry, and other sources (Chen et al, ; Li & Zhao, ; Sailor, ).…”

Spatial Distribution of Sensible and Latent Heat Flux in the City of Basel (Switzerland)

“…Each component of the urban energy balance after [1] R n + Q F = Q H + Q E + ΔQ S + ΔQ A (1) with the net radiation R n , the sensible (Q H ) and latent (Q E ) heat flux, the storage heat flux ΔQ S , and the anthropogenic heat flux Q F being evaluated in a separate work package [2] and the net advection ΔQ A is assumed to be zero. This study concentrates on the fluxes of sensible and latent heat, which are strongly modified by the properties of the urban surface, i.e., three-dimensional (3-D) geometry, high roughness, impervious surfaces, complex source/sink distribution, and injections of heat and water into the urban atmosphere by human activities (traffic, heating, waste management, etc.…”