2001: Looking for a universal thermal climate index (UTCI) for outdoor applications

The International Society of Biometeorology ISB has established a commission to review recent advances in the assessment of the outdoor thermal environment, and to integrate new knowledge and concerns into a Universal Thermal Climate Index UTCI, see: www.dwd.de/UTCI. An essential requirement for a UTCI is that the same index value must always have the same thermophysiological meaning, independent of the combination of the meteorological input values. Therefore only an index which takes into account all mechanisms of heat exchange can be universally valid and can be applied to all climates, all regions, every season, every scale, and in general, every biometeorological application. A brief presentation of the requirements for a UTCI is given, followed by an explanation of the Klima-Michel-model KMM, an operational model already meeting several UTCI requirements. Selected applications of KMM are given to refute the objection that complex models are not appropriate for daily applications