Henning Staiger

The perceived temperature - a versatile index for the assessment of the human thermal environment. Part A: scientific basics

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.

Modelling solar UV radiation in the past: comparison of algorithms and input data

The objectives of the COST action 726 are to establish long-term changes of UV-radiation in the past, which can only be derived by modelling with good and available proxy data. To find the best available models and input data, 16 models have been tested by modelling daily doses for two years of data measured at four stations distributed over Europe. The modelled data have been compared with the measured data, using different statistical methods. Models that use Cloud Modification Factors for the UV spectral range, derived from co-located measured global irradiance, give the best results.

Herzinfarktereignis und Wetter

ZusammenfassungExtreme Temperatur- und Dampfdruckverhältnisse im gemäßigten Klima Hamburgs können den Wettereinfluß auf interdiume Schwankungen von Morbiditätsraten nicht hinreichend erklären. In Form der Abweichung von der jeweiligen meteorologischen Vorgeschichte wurden für jeden Tag des Zeitraumes Oktober 1975 bis September 1977 das bekannte Temperatur-Feuchte-Mileu und neu die zyklonalen Verhältnisse der Atmosphäre (Vorticity) objektiv klassifiziert. Ihre Eignung für biometeorologische Untersuchungen wird an einem Kollektiv von Patienten mit akutem Herzinfarkt demonstriert. Es wird ein unterschiedlicher Wettereinfluß auf den Herzinfarkteintritt bei Patienten mit manifester Angina pectoris in der Zeit vor dem Herzinfarkt und solchen ohne dieses Prodromalsymptom nachgewiesen. Patienten ohne Prodomalsymptom werden im Vergleich zu den anderen bei Änderungen zum wärmer/feuchten Milieu stärker betroffen sowie bei starken Änderungen der zyklonalen Verhältnisse der Atmosphäre, unabhängig von deren Richtung.SummaryExtreme values of temperature and/or humidity in the temperate climate of Hamburg are not able to explain the influence of weather on day-to-day fluctuations of morbidity. Short term changes in weather are described by two objective classifications as deviation from the meteorological past: 1. the temperature-humidity-environment, derived from values of temperature and water vapour pressure at 07.00 h, 2. changes in the cyclonality, derived from the difference of 500 and 850 mbar vorticity values. Their suitability for human biometeorology is illustrated with a material of 1262 subjects who suffered from acute myocardial infarction. For these investigated cases it was known whether angina pectoris was already manifest before the infarction or not. The daily weather conditions have a significant effect on the incidence of acute myocardial infarction according to angina pectoris. Compared to subjects with angina pectoris those without angina pectoris show an increased susceptibility to infarction during changes in weather conditions to warmer/more humid and also during all strong changes in the cyclonality whereby the temperature-humidity-environment seems to leave only the role of an indicator too. Persons with a preceeding angina pectoris are more sensitive agains rapid changes in weather conditions.