The Universal Thermal Climate Index UTCI Goal and State of COST Action 730 and ISB Commission 6

1. Meteorological Institute Faculty of Forest and Environmental Sciences The Universal Thermal Climate Index UTCIGoal and State of COST Action 730 and ISB Commission 6 Gerd Jendritzky1, George Havenith2, Philipp Weihs3, Ekaterina Batchvarova4, and Richard DeDear5 1Meteorological Institute, Univ of Freiburg, Germany 2Loughborough Univ, Loughborough, U.K. 3Univ Soil Culture, Vienna, Austria 4Nat. Inst. Meteorology Hydrology, Sofia, Bulgaria 5Dept. Physical Geography, Macquarie Univ, Sidney, Australia gerd.jendritzky@meteo.uni-freiburg.de

2. Sun or other radiation source Sweat evaporation respiration Direct radiation Infra-red radiation clothing M convection External work Reflected radiation infra-red radiation conduction Avenues of Heat Exchange (G. Havenith, 2001)

3. The human heat budget M + W + Q* + QH + QL + QSW + QRe + S = 0 M Metabolic rate W Mechanical power Q* Radiation budget (Tmrt) QH Turbulent flux of sensible heat (Ta,v) QL Turbulent flux of latent heat (diffusion water vapour) (vp,v) QSW Turbulent flux of latent heat (sweat evaporation) (vp,v) QRe Respiratory heat flux (sensible and latent) (Ta,vp) S Storage

4. Why UTCI? • Simple thermal indices do not consider sufficiently: (1) heat exchange theory (2) thermo-physiology • Thus simple thermal indices show inacceptable shortcomings • Last 35-40 years: Heat budget modelling • Need: Dose-response related procedure • Integration of new knowledge and concerns • Need: Harmonization  UTCI (ISB, COST, WMO, ISO)

5. Main objective of joint activities of ISB Comm. 6 and COST Action 730 on UTCI: • to develop and make easily available • a physiologically assessment model of the thermal environment • based on one of the “most advanced thermo-physiological models” • in order to significantly enhance applications related to health and well-being in the fields of: • public weather service • public health system • precautionary planning • climate impact research > 40 scientists from 22 countries (Europe, IL, CA, AUS, NZ)

6. Tmrt vp v The UTCI model weather data Single index UTCI Ta

7. Tmrt vp v The UTCI model weather data Multi-node Thermo-physiogical Model Single index UTCI Ta

8. Principle of Fiala‘s 340 node model Fiala et al. 2001

9. Tmrt vp v The UTCI model weather data Multi-node Thermo-physiogical Model + Clothing Model Single index UTCI Ta

10. Ta °C

11. Behaviour Environment Skin Heat Temperature Sweating Exchange Threshold - + T skin Skin Blood Flow Heat Exchange T + Shivering core - Core Temperature Threshold Brain Controllers Human Physiology Model Control System Havenith, 2001

12. Tmrt vp v The UTCI model Average human response weather data Tcore , local Tskin , skin wettedness thermal sensation, etc. Multi-node Thermo-physiogical Model + Clothing Model Single index UTCI Ta

13. Model response in Reference Conditions 75.000 simulations Fiala 340 node model Ta °C +50 1Rectal temperature 2Mean skin temperature 3Face skin temperature 4Skin blood flow 5Skin wettedness 6Sweating 7Shivering 0 -50

14. Global Ta / vp distribution65535 random samle out of 747.520.000 data (0,00877%); ECHAM4/T106 Ctrl TT 47,42 °C max -74,60 °C min vp 40,19 hPa max 0,03 hPa min TD 28,96 °C max -76,89 °C min

15. Summary: Basic features of UTCI • Thermo-physiologically significant in the whole range of heat exchange conditions • Valid in all climates, seasons and scales • Independent of individual characteristics • Prediction of whole body and local (WCI) thermal effects • Based on the advanced 340-node model (Fiala) • Met input data: Ta, v, vp, Tmrt • Temperature scale index • Reference conditions: Walking 4km/h (2,3 met), Tmrt = Ta, v(10m) = 0,5 m/s, RH = 50%, levelled off at vp = 20 hPa • Fast calculation procedure for operational use • International standard for human biometeorological core applications (WMO-Guideline, ISO(?))