The most important meteorological parameter affecting the human energy balance during sunny weather conditions is the mean radiant temperature T(mrt). It considers the uniform temperature of a surrounding surface giving off blackbody radiation, which results in the same energy gain of a human body given the prevailing radiation fluxes. This energy gain usually varies considerably in open space conditions. In this paper, the model 'RayMan', used for the calculation of short- and long-wave radiation fluxes on the human body, is presented. The model, which takes complex urban structures into account, is suitable for several applications in urban areas such as urban planning and street design. The final output of the model is, however, the calculated T(mrt), which is required in the human energy balance model, and thus also for the assessment of the urban bioclimate, with the use of thermal indices such as predicted mean vote (PMV), physiologically equivalent temperature (PET) and standard effective temperature (SET*). The model has been developed based on the German VDI-Guidelines 3789, Part II (environmental meteorology, interactions between atmosphere and surfaces; calculation of short- and long-wave radiation) and VDI-3787 (environmental meteorology, methods for the human-biometeorological evaluation of climate and air quality for urban and regional planning. Part I: climate). The validation of the results of the RayMan model agrees with similar results obtained from experimental studies.

The physiological equivalent temperature, PET, is a thermal index derived from the human energy balance. It is well suited to the evaluation of the thermal component of different climates. As well as having a detailed physiological basis, PET is preferable to other thermal indexes like the predicted mean vote because of its unit ( degrees C), which makes results more comprehensible to urban or regional planners, for example, who are not so familiar with modern human-biometeorological terminology. PET results can be presented graphically or as bioclimatic maps. Graphs mostly display the temporal behaviour of PET, whereas spatial distribution is specified in bioclimatic maps. In this article, some applications of PET are discussed. They relate to the evaluation of the urban heat island in cities in both temperate climates and warm climates at high altitude. The thermal component of the microclimate in the trunk space of a deciduous forest is also evaluated by PET. As an example of the spatial distribution of PET, a bioclimatic map for Greece in July (Mediterranean climate) is presented.

Urban planners are increasingly paying more attention to the topic of UHI. Within the framework of the EU-UHI Project, an industrial area inside the municipality of Modena was selected as a pilot-area for the Emilia-Romagna Region. In this paper we present some results obtained with RayMan, a model which estimates bioclimatic discomfort based on the human radiative budget. Some simulations of the impact of mitigation measures have been carried out, taking into account the insertion of greenery and building modifications. Both intra-diurnal and whole day effects have been compared.

ABSTRACT

Bioclimate conditions at Sun Moon Lake, one of Taiwan's most popular tourist destinations, are presented. Existing tourism-related climate is typically based on mean monthly conditions of air temperature and precipitation and excludes the thermal perception of tourists. This study presents a relatively more detailed analysis of tourism climate by using a modified thermal comfort range for both Taiwan and Western/Middle European conditions, presented by frequency analysis of 10-day intervals. Furthermore, an integrated approach (climate tourism information scheme) is applied to present the frequencies of each facet under particular criteria for each 10-day interval, generating a time-series of climate data with temporal resolution for tourists and tourism authorities.

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Summary• Water availability and flux and carbon isotope and other chemical compositions of wood, foliage and phloem sap were quantified in a replicated field test examining the effects of exposure (north-east, south-west) and stem density on beech ecophysiology ( Fagus sylvatica ).• Standard techniques for quantifying water potential, water flux in stems and carbon isotope composition of wood and foliage were complemented with chemical analysis of phloem sap collected using the 'phloem bleeding' technique.• Phloem sap was similar in composition to other hardwoods. The δ 13 C signatures of sap reflected short-term fluctuations in water availability and intercepted radiation, whereas foliar δ 13 C was a poor reflection of current environmental conditions. • δ 13 C of tree rings suggested that the south-west-facing site experienced a greater shortage of water during summer than the paired north-east-facing site. However, phloem δ 13 C analysis showed that interpreting the effects of water availability using δ 13 C might be confounded by radiation. Better integration of hydrological models with reliable indices of water stress in beech will be required for reliable predictions of growth, especially if (when) climates change.

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