The Perceived Temperature (PT) is an equivalent temperature based on a complete heat budget model of the human body. It has proved its suitability for numerous applications across a wide variety of scales from micro to global and is successfully used both in daily forecasts and climatological studies. PT is designed for staying outdoors and is defined as the air temperature of a reference environment in which the thermal perception would be the same as in the actual environment. The calculation is performed for a reference subject with an internal heat production of 135 W m(-2) (who is walking at 4 km h(-1) on flat ground). In the reference environment, the mean radiant temperature equals the air temperature and wind velocity is reduced to a slight draught. The water vapour pressure remains unchanged. Under warm/humid conditions, however, it is implicitly related to a relative humidity of 50%. Clothing is adapted in order to achieve thermal comfort. If this is impossible, cold or heat stress will occur, respectively. The assessment of thermal perception by means of PT is based on Fanger's Predicted Mean Vote (PMV) together with additional model extensions taking account of stronger deviations from thermal neutrality. This is performed using a parameterisation based on a two-node model. In the cold, it allows the mean skin temperature to drop below the comfort value. In the heat, it assesses additionally the enthalpy of sweat-moistened skin and of wet clothes. PT has the advantages of being self-explanatory due to its deviation from air temperature and being--via PMV--directly linked to a thermo-physiologically-based scale of thermal perception that is widely used and has stood the test of time. This paper explains in detail the basic equations of the human heat budget and the coefficients of the parameterisations.

Application of thermal indices has become very popular over the last three decades. It is mostly aimed at urban areas and is also used in weather forecasting, especially for heat health warning systems. Recent studies also show the relevance of thermal indices and their justification for thermal perception. Only twelve out of 165 indices of human thermal perception are classified to be principally suitable for the human biometeorological evaluation of climate for urban and regional planning: this requests that the thermal indices provide an equivalent air temperature of an isothermal reference with minor wind velocity. Furthermore, thermal indices must be traceable to complete human energy budget models consisting of both a controlled passive system (heat transfer between body and environment) and a controlling active system, which provides a positive feedback on temperature deviations from neutral conditions of the body core and skin as it is the case in nature. Seven out of the twelve indices are fully suitable, of which three overlap with the others. Accordingly, the following four indices were selected as appropriate: Universal Thermal Climate Index (UTCI), Perceived Temperature (PTJ), Physiologically Equivalent Temperature (PET), and rational Standard Effective Temperature (SET*).

The objective of this study is to investigate the climate sensitivity of health in a moderate climate of SW Germany. Daily mortality rates for the 30 yr period 1968-1997 for Baden-Württem-berg (SW Germany) have been investigated with regard to the possible impacts of the thermal environment. A complete heat budget model of the human being (Klima-Michel model with outcome 'perceived temperature') has been used to assess the atmospheric conditions of heat exchange. Mortality data show a marked seasonal pattern with a minimum in summer and a maximum in winter. During the seasonal minimum in summer, death rates rise sharply with increasing heat load, reaching highest values during pronounced heat waves. Under comfortable conditions, mortality data show the lowest rates. Increasing cold stress also causes death rates to rise. In addition, thermal changes on a time scale of 1 wk have been considered in comparison to short-term exposures. In all seasons changes towards 'warmer' conditions in terms of perceived temperature result in adverse effects, while changes to 'colder' conditions provide relief. This is unexpected for the winter. The daily correlation coefficients between the deviations of perceived temperature and the deviations of mortality rate from the smoothed values (Gaussian filter, 101 d) show a pronounced seasonal pattern with significant differences from zero between March and August. From the end of June to the beginning of July, about 25% of the variance in the deviations of mortality rate from the smoothed values can be explained by the effects of the thermal environment. The winter values show only non-significant correlations, strong day-to-day variability, but marked time lags of 8 d and more, while in summer there is practically no difference in the results between the zero and 1 d lags. Cold spells lead to excess mortality to a relatively small degree, which lasts for weeks. The mortality increase during heat waves is more pronounced, but is followed by lower than average values in subsequent weeks. KEY WORDS: Climate impact · Thermal environment · Mortality · Perceived temperature · SW Germany Resale or republication not permitted without written consent of the publisherClim Res 21: [91][92][93][94][95][96][97][98][99][100][101][102][103] 2002 a certain 'acclimatisation' will develop, which makes it easier to deal with. Exposure to extreme thermal conditions, however, increases the risk of physiological disturbances considerably. The impairment of the state of health can lead to illness or even death. Especially people with respiratory and cardiovascular diseases, young children and older people, whose capacity to adapt is no longer sufficient, are affected (Eurowinter Group 1997, Guest et al. 1999.The primary objective of this research is to investigate the climate sensitivity of human health of the population in the moderate climate of SW Germany. The effects of the thermal environment on mortality is explored over the whole year, seasonally, and for summer and winter extreme temp...

The important requirement that COST Action 730 demanded of the physiological model to be used for the Universal Thermal Climate Index was its capability of accurate simulation of the human thermophysiological responses across a wide range of relevant environmental conditions, such as conditions corresponding to the selection of all habitable climates and their seasonal changes, and transient conditions representing temporal variation of outdoor conditions. In the first part of this study available heat budget/two-node models and multi-node thermophysiological models were evaluated by direct comparison over the wide spectrum of climatic conditions. The UTCI-Fiala model predicted most reliably the average human thermal response which was showed by least deviations from physiologically plausible responses when compared to other models. In the second part of the study, this model was, therefore, subjected to extensive validation using results of human subject experiments for a range of relevant (steady-state and transient) environmental conditions. The UTCI-Fiala multi-node model proved its ability to predict adequately the human physiological response for a variety of moderate and extreme conditions represented in the COST 730 database. The mean skin and core temperatures were predicted with average root-meansquare deviations of 1.35 ± 1.00 °C and 0.32 ± 0.20 °C, respectively. In the first part of this study available heat budget/two-node models and multi-node thermophysiological models were evaluated by direct comparison over the wide spectrum of climatic conditions. The UTCI-Fiala model predicted most reliably the average human thermal response which was showed by least deviations from physiologically plausible responses when compared to other models. In the second part of the study, this model was, therefore, subjected to extensive validation using results of human subject experiments for a range of relevant (steadystate and transient) environmental conditions. The UTCI-Fiala multi-node model proved its ability to predict adequately the human physiological response for a variety of moderate and extreme conditions represented in the COST 730 database. The mean skin and core temperatures were predicted with average root-mean-square deviations of 1.35 ± 1.00 °C and 0.32 ± 0.20 °C, respectively.

After 2003, another hot summer took place in Western and Central Europe in 2015. In this study, we compare the characteristics of the two major heat waves of these two summers and their effect on the heat related mortality. The analysis is performed with focus on South-West Germany (Baden-Württemberg). With an additional mean summer mortality of +7.9% (2003) and +5.8% (2015) both years mark the top-two records of the summer mortality in the period 1968-2015. In each summer, one major heat wave contributed strongly to the excess summer mortality: In August 2003, daily mortality reached anomalies of +70% and in July 2015 maximum deviations of +56% were observed. The August 2003 heat wave was very long-lasting and characterized by exceptional high maximum and minimum temperatures. In July 2015, temperatures were slightly lower than in 2003, however, the high air humidity during the day and night, lead to comparable heat loads. Furthermore, the heat wave occurred earlier during the summer, when the population was less acclimated to heat stress. Using regional climate models we project an increasing probability for future 2003-and 2015-like