Influence of ground surface characteristics on the mean radiant temperature in urban areas

Lindberg, Fredrik; Onomura, Shiho; Grimmond, Sue

doi:10.1007/s00484-016-1135-x

Cited by 86 publications

(49 citation statements)

References 38 publications

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“…However, there was a minimal difference in the albedos (0.16 versus 0.18 for asphalt and grass, respectively), and thus, the reduced T a over the moist grass aids in reducing the heat load. Results from the current study, as well as those by Taleghani et al (2016) and Lindberg et al (2016), andErell et al (2014), demonstrate that low-albedo strategies on dry surfaces may not improve the thermal comfort as expected, and that energy partitioning into latent heat (using vegetation or water) may be a more important focus in improving thermal comfort in the daytime.…”

Section: Radiative Fluxes and Urban Heat Mitigation Potentialmentioning

confidence: 48%

“…A study by Lindberg et al (2016) also assessed the influence of ground surface on T mrt using the SOLWEIG model and simultaneous observations over grass and asphalt, finding the T mrt during heat-wave episodes to be higher over the asphalt in full sunlit locations. However, there was a minimal difference in the albedos (0.16 versus 0.18 for asphalt and grass, respectively), and thus, the reduced T a over the moist grass aids in reducing the heat load.…”

Section: Radiative Fluxes and Urban Heat Mitigation Potentialmentioning

confidence: 99%

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The influence of surface type on the absorbed radiation by a human under hot, dry conditions

Hardin

Vanos

2017

Int J Biometeorol

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Given the predominant use of heat-retaining materials in urban areas, numerous studies have addressed the urban heat island mitigation potential of various "cool" options, such as vegetation and high-albedo surfaces. The influence of altered radiational properties of such surfaces affects not only the air temperature within a microclimate, but more importantly the interactions of long-and shortwave radiation fluxes with the human body. Minimal studies have assessed how cool surfaces affect thermal comfort via changes in absorbed radiation by a human (R abs ) using real-world, rather than modeled, urban field data. The purpose of the current study is to assess the changes in the absorbed radiation by a human-a critical component of human energy budget models-based on surface type on hot summer days (air temperatures >38.5 • C). Field tests were conducted using a high-end microclimate station under predominantly clear sky conditions over ten surfaces with higher sky view factors in Lubbock, Texas. Three methods were used to measure and estimate R abs : a cylindrical radiation thermometer (CRT), a net radiometer, and a theoretical estimation model. Results over dry surfaces suggest that the use of high-albedo surfaces to reduce overall urban heat gain may not improve acute human thermal comfort in clear conditions due to increased reflected radiation. Further, the use of low-cost instrumentation, such as the CRT, shows potential in quantifying radiative heat loads within urban areas at temporal scales of 5-10 min or greater, yet further research is needed. Fine-scale radiative information in urban areas can aid in the decision-making process for urban heat mitigation using non-vegetated urban surfaces, with surface type choice is dependent on the need for short-term thermal comfort, or reducing cumulative heat gain to the urban fabric.

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Section: Radiative Fluxes and Urban Heat Mitigation Potentialmentioning

confidence: 48%

Section: Radiative Fluxes and Urban Heat Mitigation Potentialmentioning

confidence: 99%

The influence of surface type on the absorbed radiation by a human under hot, dry conditions

Hardin

Vanos

2017

Int J Biometeorol

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“…As ΔQ S is the net change in heat stored per time from changes in the surface and internal material temperatures, to use ESTM with instantaneous satellite data, a continuous time series is needed. In the morning, a sinusoidal relation between the outdoor air temperature (T a ) and surface temperature (T S ) difference is assumed (Lindberg et al 2008(Lindberg et al , 2016:…”

Section: Sites and Meteorological Forcing Datamentioning

confidence: 99%

Urban storage heat flux variability explored using satellite, meteorological and geodata

Lindberg

Olofson

Sun

et al. 2020

Theor Appl Climatol

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The storage heat flux (ΔQ S) is the net flow of heat stored within a volume that may include the air, trees, buildings and ground. Given the difficulty of measurement of this important and large flux in urban areas, we explore the use of Earth Observation (EO) data. EO surface temperatures are used with ground-based meteorological forcing, urban morphology, land cover and land use information to estimate spatial variations of ΔQ S in urban areas using the Element Surface Temperature Method (ESTM). First, we evaluate ESTM for four "simpler" surfaces. These have good agreement with observed values. ESTM coupled to SUEWS (an urban land surface model) is applied to three European cities (Basel, Heraklion, London), allowing EO data to enhance the exploration of the spatial variability in ΔQ S. The impervious surfaces (paved and buildings) contribute most to ΔQ S. Building wall area seems to explain variation of ΔQ S most consistently. As the paved fraction increases up to 0.4, there is a clear increase in ΔQ S. With a larger paved fraction, the fraction of buildings and wall area is lower which reduces the high values of ΔQ S .

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“…These can either moderate the heat caused by incident solar radiation through either shading (reduction in both shortwave radiation (SWR) and longwave radiation (LWR) [2,3]), reflection or evapotranspiration, or can exacerbate the heat through absorption and re-radiation (radiant exitance) of LWR [4]. At night, elements can cool off through re-radiation to the cold night sky or can retain heat if thermal mass is high and other objects obscure their sky view (low sky view factor (SVF) [5]).…”

Section: Introductionmentioning

confidence: 99%

Quantifying radiation from thermal imaging of residential landscape elements

Loveday

Loveday²,

Byrne

et al. 2017

Renew. Energy Environ. Sustain.

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Abstract. The microclimate of a residential landscape can affect both the energy use in your home and the human thermal comfort in your garden, ultimately affecting the heat in the neighbourhood or precinct. A thermal imaging camera provides information about the temperature of surfaces. By using Stefan-Boltzmann's law and the surface properties, these temperatures can be used to calculate the emission of longwave radiation (radiant exitance) in W m À2 . A thermal camera was used to determine the amount of radiant exitance from a range of residential landscape elements. A standard procedure for capturing these images was developed, taking into account factors which affect the quality of the radiometric data. A quantitative database comparing this radiation has been compiled for different times of day and different seasons. The sky view factor of these elements was chosen such that it was as close to 1 as possible. For a particular landscape design, areas of each landscape element can be measured and the amount of radiation reduced or emitted at different times can be calculated. This data can be used to improve landscape designs to reduce home energy use and human thermal comfort through shading and reduction of surfaces which emit longwave radiation close to the house.

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Influence of ground surface characteristics on the mean radiant temperature in urban areas

Cited by 86 publications

References 38 publications

The influence of surface type on the absorbed radiation by a human under hot, dry conditions

The influence of surface type on the absorbed radiation by a human under hot, dry conditions

Urban storage heat flux variability explored using satellite, meteorological and geodata

Quantifying radiation from thermal imaging of residential landscape elements

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