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

A. W. Hardin, J. K. Vanos

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

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 short-wave radiation fluxes with the human body. Minimal studies have assessed how cool surfaces affect thermal comfort via changes in absorbed radiation by a human (Rabs) 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 > 38.5C). 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 Rabs: 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.

Original languageEnglish (US)
Pages (from-to)43-56
Number of pages14
JournalInternational Journal of Biometeorology
Volume62
Issue number1
DOIs
StatePublished - Jan 1 2018
Externally publishedYes

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Keywords

  • Absorbed radiation
  • Albedo
  • Extreme heat
  • Thermal comfort
  • Urban climate
  • Urban heat island

ASJC Scopus subject areas

  • Ecology
  • Atmospheric Science
  • Health, Toxicology and Mutagenesis

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