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Deriving the operational procedure for the Universal Thermal Climate Index (UTCI)

Bröde, Peter; Fiala, Dusan; Blazejczyk, Krzysztof; Holmér, Ingvar LU ; Jendritzky, Gerd; Kampmann, Bernhard; Tinz, Birger and Havenith, George (2012) In International Journal of Biometeorology 56(3). p.481-494
Abstract
The Universal Thermal Climate Index (UTCI) aimed for a one-dimensional quantity adequately reflecting the human physiological reaction to the multi-dimensionally defined actual outdoor thermal environment. The human reaction was simulated by the UTCI-Fiala multi-node model of human thermoregulation, which was integrated with an adaptive clothing model. Following the concept of an equivalent temperature, UTCI for a given combination of wind speed, radiation, humidity and air temperature was defined as the air temperature of the reference environment, which according to the model produces an equivalent dynamic physiological response. Operationalising this concept involved (1) the definition of a reference environment with 50% relative... (More)
The Universal Thermal Climate Index (UTCI) aimed for a one-dimensional quantity adequately reflecting the human physiological reaction to the multi-dimensionally defined actual outdoor thermal environment. The human reaction was simulated by the UTCI-Fiala multi-node model of human thermoregulation, which was integrated with an adaptive clothing model. Following the concept of an equivalent temperature, UTCI for a given combination of wind speed, radiation, humidity and air temperature was defined as the air temperature of the reference environment, which according to the model produces an equivalent dynamic physiological response. Operationalising this concept involved (1) the definition of a reference environment with 50% relative humidity (but vapour pressure capped at 20 hPa), with calm air and radiant temperature equalling air temperature and (2) the development of a one-dimensional representation of the multivariate model output at different exposure times. The latter was achieved by principal component analyses showing that the linear combination of 7 parameters of thermophysiological strain (core, mean and facial skin temperatures, sweat production, skin wettedness, skin blood flow, shivering) after 30 and 120 min exposure time accounted for two-thirds of the total variation in the multi-dimensional dynamic physiological response. The operational procedure was completed by a scale categorising UTCI equivalent temperature values in terms of thermal stress, and by providing simplified routines for fast but sufficiently accurate calculation, which included look-up tables of pre-calculated UTCI values for a grid of all relevant combinations of climate parameters and polynomial regression equations predicting UTCI over the same grid. The analyses of the sensitivity of UTCI to humidity, radiation and wind speed showed plausible reactions in the heat as well as in the cold, and indicate that UTCI may in this regard be universally useable in the major areas of research and application in human biometeorology. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Outdoor climate, Index, Thermal stress, Thermophysiology, Simulation model, Thermal comfort
in
International Journal of Biometeorology
volume
56
issue
3
pages
481 - 494
publisher
Springer
external identifiers
  • wos:000303461000007
  • scopus:84860359130
ISSN
1432-1254
DOI
10.1007/s00484-011-0454-1
language
English
LU publication?
yes
id
affff3f9-52ef-473f-8ad9-fce611edcbb8 (old id 1969673)
date added to LUP
2011-05-26 09:43:09
date last changed
2017-11-12 03:37:12
@article{affff3f9-52ef-473f-8ad9-fce611edcbb8,
  abstract     = {The Universal Thermal Climate Index (UTCI) aimed for a one-dimensional quantity adequately reflecting the human physiological reaction to the multi-dimensionally defined actual outdoor thermal environment. The human reaction was simulated by the UTCI-Fiala multi-node model of human thermoregulation, which was integrated with an adaptive clothing model. Following the concept of an equivalent temperature, UTCI for a given combination of wind speed, radiation, humidity and air temperature was defined as the air temperature of the reference environment, which according to the model produces an equivalent dynamic physiological response. Operationalising this concept involved (1) the definition of a reference environment with 50% relative humidity (but vapour pressure capped at 20 hPa), with calm air and radiant temperature equalling air temperature and (2) the development of a one-dimensional representation of the multivariate model output at different exposure times. The latter was achieved by principal component analyses showing that the linear combination of 7 parameters of thermophysiological strain (core, mean and facial skin temperatures, sweat production, skin wettedness, skin blood flow, shivering) after 30 and 120 min exposure time accounted for two-thirds of the total variation in the multi-dimensional dynamic physiological response. The operational procedure was completed by a scale categorising UTCI equivalent temperature values in terms of thermal stress, and by providing simplified routines for fast but sufficiently accurate calculation, which included look-up tables of pre-calculated UTCI values for a grid of all relevant combinations of climate parameters and polynomial regression equations predicting UTCI over the same grid. The analyses of the sensitivity of UTCI to humidity, radiation and wind speed showed plausible reactions in the heat as well as in the cold, and indicate that UTCI may in this regard be universally useable in the major areas of research and application in human biometeorology.},
  author       = {Bröde, Peter and Fiala, Dusan and Blazejczyk, Krzysztof and Holmér, Ingvar and Jendritzky, Gerd and Kampmann, Bernhard and Tinz, Birger and Havenith, George},
  issn         = {1432-1254},
  keyword      = {Outdoor climate,Index,Thermal stress,Thermophysiology,Simulation model,Thermal comfort},
  language     = {eng},
  number       = {3},
  pages        = {481--494},
  publisher    = {Springer},
  series       = {International Journal of Biometeorology},
  title        = {Deriving the operational procedure for the Universal Thermal Climate Index (UTCI)},
  url          = {http://dx.doi.org/10.1007/s00484-011-0454-1},
  volume       = {56},
  year         = {2012},
}