Gerd Jendritzky, Germany The Universal Thermal Climate Index UTCI COST Action 730 www.dwd.de/UTCI Gerd Jendritzky, Germany George Havenith, U.K. Philipp Weihs, Austria Ekaterina Batchvarova, Bulgaria gerd.jendritzky@meteo.uni-freiburg.de
Why UTCI? Assessment of the thermal environment: Key issue in human biometeorology History: >100 simple thermal indices Last 35 years: Heat budget modelling Integration of new knowledge and concerns Need: Harmonization UTCI (ISB, WMO) COST Action (Example: UV-Index) gerd.jendritzky@meteo.uni-freiburg.de
George Havenith, 2003
M + W + Q* + QH + QL + QSW + QRe + S = 0 The human heat budget M + W + Q* + QH + QL + QSW + QRe + S = 0 M Metabolic rate W Mechanical power Q* Radiation budget (Tmrt,v) QH Turbulent flux of sensible heat (Ta,v) QL Turbulent flux of latent heat (diffusion water vapour) (e,v) QSW Turbulent flux of latent heat (sweat evaporation) (e,v) QRe Respiratory heat flux (sensible and latent) (Ta,e) S Storage
Problem: Insufficiency of available assessment procedures Problem: Insufficiency of available assessment procedures. Thus strong need to make use of the progress in science and modelling in thermophysiology of the last 30-40 years. Strategy: Bundling of interdisciplinary expertise in a COST Action 730 in close cooperation with ISB Commission 6 on UTCI. Experts from 18 countries plus WMO in three working groups : WG1 Thermophysiological modelling and testing WG2 Meteorological and environmental data WG3 Applications. gerd.jendritzky@meteo.uni-freiburg.de
Thermophysiological Assessment of the Thermal Environment Descriptive term Thermophysiology Meteorology PMV - PT* °C PET °C OUT_SET* °C AT 1,2,3 °C (WCT) °C Tsk °C SR kgs-1 ESK Wm-2 Wsk % Icl clo etc. A s e m n t WG1 Ta Tmrt v e Heat budget models
Action 730 on UTCI Fiala et al. 2001
Simulated whole body and local thermophysiological variables Mean skin temperature, Tsk,m Head core temperature (hypothalamus), Thy Total evaporative heat loss from the skin, Esk Skin wettedness, wsk Local skin temperatures of face and hands, Tsk,f,h Cooling time for Tsk,f,h < 0°C Assessment problem!
Thermophysiological Assessment of the Thermal Environment Descriptive term Thermophysiology Meteorology WG2 PMV - PT* °C PET °C OUT_SET* °C AT 1,2,3 °C (WCT) °C Tsk °C SR kgs-1 ESK Wm-2 Wsk % Icl clo etc. A s e m n t Ta Tmrt v e Heat budget models
Tmrt Uniform temperature of a black body enclodure that results in the same radiant heat exchange as under actual conditions Direct solar radiation Diffuse solar radiation Reflected solar radiation Infrared radiation from the sky Infrared radiation from the surroundings
Projected Surface Area gerd.jendritzky@meteo.uni-freiburg.de
WG 3 Applications Public weather service Public health system Precautionary planning Climate impact research
Selected subproplems Heat budget modelling WG1 Assessment of physiological variables WG1 Acclimatisation WG1 Meteorological input, in particular radiation Tmrt WG2 Definition of areas of validity, requirements WG2 Applications (Needs of users) WG3
Summary: Basic features of UTCI Thermophysiologically significant in the whole range of heat exchange conditions Valid in all climates, seasons and scales Steady-state conditions: Applicability Independent of individual characteristics Prediction of whole body and local thermal effects Based on the most advanced multi-node models Temperature scale index International standard for human biometeorological core applications