Thermal bioclimate in Strasbourg - the 2003 heat wave

This case study highlights the implications of the 2003 heat wave for the city of Strasbourg, France. The urban centers of France and other European countries were particularly affected by the heat wave. In some urban areas, the mortality rate was 60% above the expected value (Institute de Veille Sanitaire, 2003). The 2003 heat wave demonstrated once again that populations in urban centers are much more affected by extreme meteorological events than people living in rural areas. The aim of this analysis is to explore differences in thermal comfort conditions of (a) the city center of Strasbourg, and (b) its hinterland. The differences in thermal conditions existing between rural and urban areas are quantified by using a bio-climatological index termed physiologically equivalent temperature (PET). This index is based on the human energy balance and builds a relevant index for the quantification of the thermal environment of humans. We calculate the PET for the years 2003 and 2004 to highlight the temporal changes in the severity of climate extremes. The spatial scope of this study is improved compared to previous works in the field through the inclusion of PET calculations for five different sites on a central place in Strasbourg (Place Kléber). The calculations are characterized by different sky view factors and are compared to the reference site, which is located in a rural area. In the rural hinterland (Entzheim), the analysis of PET indicates a strong cold thermal stress during the winter months but no significant stress in summer. In 2003, summer temperatures were sensed as warmer compared to other years, but did not reach the extreme temperatures that may cause severe heat stress. For both the rural and the urban study sites PET was higher in the summer of 2003 than in 2004, which reflects the inferior thermal conditions in the urban area during the heat wave in 2003. For the entire study period, urban and rural day-time PET reached similar maximal values. Strong differences in PET, however, were observed between the rural and urban areas at night-time. The study of PET for several study sites on a central place in the city (Place Kléber) of Strasbourg for the years 2003 and 2004 showed that the sites with a higher sky view factor present higher values than sites with a lower sky view factor. The comparison of these PET values (Place Kléber) to the results for the rural area showed that during the day and the night the rural city of Entzheim has the lowest PET. During the day, the site at Place Kléber, which is located under a tree, has the lowest PET. The comparison of PET for the years 2003 and 2004 shows that PET in 2003 was about 5 to 7 K higher.     

Thermal sensation of people performing recreational activities in shadowy environment: a case study from Turkey

The objective of this study is to determine human thermal comfort conditions in the recreational areas of the city of Erzurum using an 18-year data set of the five warmest months of the year obtained from the meteorological station established in the rural area of the city at 1400 local time and discussing the applicability of a new approach that climatic or bioclimatic comfort conditions under some tree species may be comparable to those under some cloudiness categories. It was found by concluding that the effects of cloudiness and shadows of selected tree species may not be the same on thermal comfort conditions that people can experience cold stress under dense shadows especially in spring and autumn months and heat stress under weak shadows in summer months in recreational areas. It was suggested that, in order to prevent people in recreational areas from heat and cold stress, great care must be taken in the plantation of recreational areas and deciduous tree species, rather than coniferous, which can foliate late, should be used.     

Urban heat island and differences in outdoor comfort levels in Glasgow, UK

From extensive outdoor comfort campaigns, preliminary outdoor comfort ranges have been defined for the local population of Glasgow, UK, in terms of two thermal indices: ‘Temperature Humidity Sun Wind’ (THSW) and ‘Physiological Equivalent Temperature’ (PET). A series of measurements and surveys was carried out from winter through summer 2011 during 19 monitoring campaigns. For data collection, a Davis Vantage Pro2 weather station was used, which was equipped with temperature and humidity sensors, cup anemometer with wind vane, silicon pyranometer and globe thermometer. From concurrent measurements using two weather stations, one located close to the city core and another located at a rural setting, approximately at a 15-km distance from the urban area of Glasgow, comparisons were made with regard to thermal comfort levels and to urban–rural temperature differences for different periods of the year. It was found that the two selected thermal indices (THSW and PET) closely correlate to the actual thermal sensation of respondents. Moreover, results show that the urban site will have fewer days of cold discomfort, more days of ‘neutral’ thermal sensation and slightly higher warm discomfort. The most frequent urban heat island intensity was found to be around 3° C, whereas the fraction of cooling to heating degree-hours for a T _base of 65 °F was approximately 1/12th.     

Assessment of thermal bioclimate and tourism climate potential for central Europe—the example of Luxembourg

Tourism destinations often require information about climate to assess their climate potential. This can be performed in terms of mean conditions of relevant climatological parameters. For a user-friendly analysis and visualization of climate data relevant for tourism application in Luxembourg, information is prepared based on the facets of climate in tourism. Information on thermal comfort/stress conditions as well as aesthetical and physical parameters is considered. In the present study, relevant and sensible factors were identified and presented. Therefore, physiologically equivalent temperature, precipitation patterns and the Climate-Tourism/Transfer-Information-Scheme are applied. In addition, extreme events relevant for heat stress are analysed based on existing data sets (i.e. heat waves of 2010). Expected climatic conditions for the future are investigated using the projections of two different regional climate models. The results concerning climate change conditions reveal increasing heat stress and sultriness but decreasing cold stress. This information is the basis for an adequate assessment to provide relevant information for different environmental planning issues as well as for the growing tourism sector of Luxembourg.     

Regional Distribution of Perceived Temperatures Estimated by the Human Heat Budget Model （the Klima-Michel Model） in South Korea

The regional distribution of perceived temperatures (PT) for 28 major weather stations in South Korea during the past 22 years (1983–2004) was investigated by employing a human heat budget model, the Klima-Michel model. The frequencies of a cold stress and a heat load by each region were compared. The sensitivity of PT in terms of the input of synoptic meteorological variables were successfully tested. Seogwipo in Jeju Island appears to be the most comfortable city in Korea. Busan also shows a high frequenc...     

A model of the ground surface temperature for micrometeorological analysis

Micrometeorological models at various scales require ground surface temperature, which may not always be measured in sufficient spatial or temporal detail. There is thus a need for a model that can calculate the surface temperature using only widely available weather data, thermal properties of the ground, and surface properties. The vegetated/permeable surface energy balance (VP-SEB) model introduced here requires no a priori knowledge of soil temperature or moisture at any depth. It combines a two-layer characterization of the soil column following the heat conservation law with a sinusoidal function to estimate deep soil temperature, and a simplified procedure for calculating moisture content. A physically based solution is used for each of the energy balance components allowing VP-SEB to be highly portable. VP-SEB was tested using field data measuring bare loess desert soil in dry weather and following rain events. Modeled hourly surface temperature correlated well with the measured data (r ² = 0.95 for a whole year), with a root-mean-square error of 2.77 K. The model was used to generate input for a pedestrian thermal comfort study using the Index of Thermal Stress (ITS). The simulation shows that the thermal stress on a pedestrian standing in the sun on a fully paved surface, which may be over 500 W on a warm summer day, may be as much as 100 W lower on a grass surface exposed to the same meteorological conditions.     

Thermal bioclimate in idealized urban street canyons in Campinas, Brazil

Among several urban design parameters, the height-to-width ratio (H/W) and orientation are important parameters strongly affecting thermal conditions in cities. This paper quantifies changes in thermal comfort due to typical urban canyon configurations in Campinas, Brazil, and presents urban guidelines concerning H/W ratios and green spaces to adapt urban climate change. The study focuses on thermal comfort issues of humans in urban areas and performs evaluation in terms of physiologically equivalent temperature (PET), based on long-term data. Meteorological data of air temperature, relative humidity, wind speed and solar radiation over a 7-year period (2003–2010) were used. A 3D street canyon model was designed with RayMan Pro software to simulate the influence of urban configuration on urban thermal climate. The following configurations and setups were used. The model canyon was 500 m in length, with widths 9, 21, and 44 m. Its height varied in steps of 2.5 m, from 5 to 40 m. The canyon could be rotated in steps of 15°. The results show that urban design parameters such as width, height, and orientation modify thermal conditions within street canyons. A northeast–southwest orientation can reduce PET during daytime more than other scenarios. Forestry management and green areas are recommended to promote shade on pedestrian areas and on façades, and to improve bioclimate thermal stress, in particular for H/W ratio less than 0.5. The method and results can be applied by architects and urban planners interested in developing responsive guidelines for urban climate issues.     

长江三角洲地区人体舒适度时空变化特征北大核心CSCD

基于1981~2020年ERA5逐小时再分析资料,采用通用热气候指数(Universal Thermal Climate Index,UTCI)计算方法,分析了气候变化背景下长江三角洲地区人体生理热响时空变化特征。研究表明:近40年长江三角洲地区人体无冷热胁迫气候条件的出现频率约为43.77%、热胁迫和冷胁迫出现频率分别约为22.42%和33.81%,其中,显著热胁迫和显著冷胁迫出现频率分别约为8.38%和1.58%;在空间分布上,长江三角洲地区无冷热胁迫气候条件的出现频率总体表现为南多北少地带性分布,兼有山区多平原少、沿海多内陆少分布特征,显著热胁迫主要出现在皖西和皖南的平原以及浙江的嘉绍平原和金衢盆地,显著冷胁迫主要出现在苏北、皖北和舟山以北的沿海岸区;在全球气候变暖背景下,长江三角洲地区UTCI值的年代际变化呈上升趋势,由1981~1990年13.83℃增加至2011~2020年14.75℃,人体生理热响应表征为冷胁迫减少、热胁迫增加、无冷热胁迫基本不变,春季无冷热胁迫时长的增加基本抵消了夏季无冷热胁迫时长的减少。     

Effect of the position of the visible sky in determining the sky view factor on micrometeorological and human thermal comfort conditions in urban street canyons

Poor daytime and night-time micrometeorological conditions are issues that influence the quality of environmental conditions and can undermine a comfortable human lifestyle. The sky view factor (SVF) is one of the essential physical parameters used to assess the micrometeorological conditions and thermal comfort levels within city streets. The position of the visible sky relative to the path of the sun, in the cardinal and ordinal directions, has not been widely discerned as a parameter that could have an impact on the micrometeorological conditions of urban streets. To investigate this parameter, different urban streets that have a similar SVF value but diverse positions of visible sky were proposed in different street directions intersecting with the path of the sun, namely N–S, NE–SW and NW–SE. The effects of daytime and night-time micrometeorological variables and human thermal comfort variables on the street were investigated by applying ENVI-met V3.1 Beta software. The results show that the position of the visible sky has a greater influence on the street’s meteorological and human thermal comfort conditions than the SVF value. It has the ability to maximise or minimise the mean radiation temperature (Tmrt, °C) and the physiological equivalent temperature (PET, °C) at street level. However, the visible sky positioned to the zenith in a NE–SW or N–S street direction and to the SW of a NW–SE street direction achieves the best daytime micrometeorological and thermal comfort conditions. Alternatively, the visible sky positioned to the NE for a NW–SE street direction, to the NW and the zenith for a NE–SW street direction and to the zenith for a N–S street direction reduces the night-time air temperature (Ta, °C). Therefore, SVF and the position of the visible sky relative to the sun’s trajectory, in the cardinal and ordinal directions, must be considered during urban street planning to better understand the resultant micrometeorological and human thermal comfort conditions.     

地表利用城市化在一次极端高温过程数值模拟中的影响

地表种类的城市化对城市区域的热力结构和局地环流都会产生巨大的影响。利用地面、高空观测资料和MODIS地表覆盖资料,使用耦合城市冠层模式(UCM)的区域中尺度数值模式(WRF),对2013年8月8日福州地区的一次极端高温天气过程进行数值模拟,研究地表利用变化对福州城市热岛效应及其对福州城市区域局地环流的影响。结果表明:地表利用的城市化使得午后城市热岛现象更加明显而夜间热岛效应呈现出减小的趋势;地表利用城市化后,中心城区的近地面风速减小,但城区与山区以及城区与海洋之间的局地热力环流明显加强,促进了山谷风和海陆风环流的发展;同时地表加热效应增强,促进了垂直运动的发展。      

A comprehensive analysis of physiologically equivalent temperature changes of Iranian selected stations for the last half century

As a preliminary and major step for land use planning of the coming years, the study of variability of the past decades’ climatic conditions with comprehensive indicators is of high importance. Given the fact that one of the affected areas by climatic change includes variability of thermal comfort, this study uses the physiologically equivalent temperature (PET) to identify and evaluate bioclimatic conditions of 40 meteorological stations in Iran. In this study, PET changes for the period of 1960 to 2010 are analyzed, with the use of Mann-Kendall non-parametric test and Pearson parametric method. The study focuses particularly on the diversity in spatio-temporal distribution of Iran’s bioclimatic conditions. The findings show that the mean frequency percentage of days with comfort is 12.9 % according to the total number of selected stations. The maximum and minimum frequency percentage with values of 17.4 and 10.3 belong to Kerman and Chabahar stations, respectively. The findings of long-term trend analysis for the period of 1960–2010 show that 55 % of the stations have significant increasing trend in terms of thermal comfort class based on the Pearson method, while it is 40 % based on Mann-Kendall test. The results indicate that the highest frequency of days with thermal comfort in the southern coasts of Iran relates to the end of autumn and winter, nevertheless, such ideal conditions for the coastal cities of Caspian Sea and even central stations of Iran relate to mid-spring and mid-autumn. Late summer and early autumn along with late spring can be identified as the most ideal times in the west and northwest part of Iran. In addition, the most important inhibiting factors of thermal comfort prove to be different across the regions of Iran. For instance, in the southern coasts, warm to very hot bioclimatic events and in the west and northwest regions, cold to very cold conditions turn out to be the most important inhibiting factors. When considering the variations across the studied period, an increase in the frequency of thermal comfort condition is observed in almost half of the stations. Moreover, based on Pearson and Mann-Kendall methods, the trend of changes in monthly averages of PET has decreased in most stations and months, which can lead to different consequences in each month and station. Thus, it is expected that due to PET changes in recent decades and to the intensified global warming conditions, Iran’s bioclimatic conditions change in a way that transfers the days with comfort to early spring and late autumn.     

热气候指数在人体舒适度预报中的适用性

为进一步提高夏季舒适度预报质量,该文根据国际生物气象研究学会制定的体感指标计算软件和国内现行指标的计算方法,引进并修正了热气候指数(UTCI),根据对2009年8月21—25日在南京信息工程大学205名军训大学生开展的问卷调查资料,对比验证了国内外多种指标,结果表明:国内指标基本能够表征人体热感觉,但仍需进一步完善;热气候指数较其他体感指标能更好地表达人体实际热舒适度,结合天气数值预报结果和SolAlt模型预报的太阳辐射,非常适宜作为南京市人体舒适度的预报指标。热气候指数的建立,提高了南京市的公共气象服务质量。     

Analysis of high-resolution simulations for the Black Forest region from a point of view of tourism climatology �C a comparison between two regional climate models (REMO and CLM)

An analysis of climate simulations from a point of view of tourism climatology based on two regional climate models, namely REMO and CLM, was performed for a regional domain in the southwest of Germany, the Black Forest region, for two time frames, 1971?C2000 that represents the twentieth century climate and 2021?C2050 that represents the future climate. In that context, the Intergovernmental Panel on Climate Change (IPCC) scenarios A1B and B1 are used. The analysis focuses on human-biometeorological and applied climatologic issues, especially for tourism purposes ?C that means parameters belonging to thermal (physiologically equivalent temperature, PET), physical (precipitation, snow, wind), and aesthetic (fog, cloud cover) facets of climate in tourism. In general, both models reveal similar trends, but differ in their extent. The trend of thermal comfort is contradicting: it tends to decrease in REMO, while it shows a slight increase in CLM. Moreover, REMO reveals a wider range of future climate trends than CLM, especially for sunshine, dry days, and heat stress. Both models are driven by the same global coupled atmosphere?Cocean model ECHAM5/MPI-OM. Because both models are not able to resolve meso- and micro-scale processes such as cloud microphysics, differences between model results and discrepancies in the development of even those parameters (e.g., cloud formation and cover) are due to different model parameterization and formulation. Climatic changes expected by 2050 are small compared to 2100, but may have major impacts on tourism as for example, snow cover and its duration are highly vulnerable to a warmer climate directly affecting tourism in winter. Beyond indirect impacts are of high relevance as they influence tourism as well. Thus, changes in climate, natural environment, demography, tourists?? demands, among other things affect economy in general. The analysis of the CLM results and its comparison with the REMO results complete the analysis performed within the project Climate Trends and Sustainable Development of Tourism in Coastal and Low Mountain Range Regions (CAST) funded by the German Federal Ministry of Education and Research (BMBF).     

Relevance of thermal environment to human health: a case study of Ondo State, Nigeria

The interconnection between weather and climate and the performance, well-being, and human health cannot be overemphasized. The relationship between them is of both local and global significance. Information about weather, climate, and thermal environment is very important to human health and medical practitioners. The most crucial environmental information needed by medical practitioners and for maintaining human health, performance, and well-being are thermal conditions. The study used meteorological variables: air temperature, relative humidity, wind speed, solar radiation, and RayMan model as an analytical tool to compute physiologically equivalent temperature (PET) in order to assess thermo-physiological thresholds in Ondo State. The study revealed that there are marked spatial and seasonal variations in the environmental thermal conditions in the study area. The results of physiologically equivalent temperature for different grades of thermal sensation and physiological stress on human beings indicate that about 60 % of the total study period (1998–2008) fall under physiological stress level of moderate heat stress (PET 31–36 °C). In derived savannah, 32.6 % out of the total study period was under strong heat stress. In view of this, the study concluded that Ondo State may likely be prone to heat-related ailments and that some of the death recorded in the State, in recent times, may be heat-related mortality, but this is difficult to ascertain because there is no postmortem records in Nigeria where it could be confirmed. This type of study is relevant to help government to improve health care interventions and achieve Millennium Development Goals in health sector.     

Thermal comfort and tourism climate changes in the Qinghai–Tibet Plateau in the last 50 years

In this paper, the thermal comfort and its changes in the Qinghai–Tibet Plateau over the last 50 years have been evaluated by using the physiological equivalent temperature (PET), and a more complete tourism climate picture is presented by the Climate–Tourism–Information Scheme (CTIS). The results show that PET classes in the Qinghai–Tibet Plateau cover six out of the nine-point thermal sensation scale — very cold, cold, cool, slightly cool, neutral and slightly warm — and cold stress is prevailing throughout the year. A small number of slightly cool/warm and neutral days occur in summer months. There occur no warm, hot and very hot days. The frequency of PET classes varies among regions, depending on their altitude/latitude conditions. Xining, Lhasa and Yushu are the top three cities in terms of thermal favorability. With global warming, annual cumulative number of thermally favorable days has been increasing, and that of cold stress has been reducing. The change is more obvious in lower elevation than that in higher elevation regions. The improving thermal comfort in the Qinghai–Tibet Plateau might be a glad tiding for local communities and tourists. Besides PET, CTIS can provide a number of additional bioclimatic information related to tourism and recreational activities. CTIS for Lhasa and Xining shows that sunshine is plentiful all the year round, and windy days occur frequently from late January to early May. This is a useful bioclimatic information for tourism authorities, travel agencies, resorts and tourists.     

The impact of heat waves on surface urban heat island and local economy in Cluj-Napoca city,Romania

The association between heat waves and the urban heat island effect can increase the impact on environment and society inducing biophysical hazards. Heat stress and their associated public health problems are among the most frequent. This paper explores the heat waves impact on surface urban heat island and on the local economy loss during three heat periods in Cluj-Napoca city in the summer of 2015. The heat wave events were identified based on daily maximum temperature, and they were divided into three classes considering the intensity threshold: moderate heat waves (daily maximum temperature exceeding the 90th percentile), severe heat waves (daily maximum temperature over the 95th percentile), and extremely severe heat waves (daily maximum temperature exceeding the 98th percentile). The minimum length of an event was of minimum three consecutive days. The surface urban heat island was detected based on land surface temperature derived from Landsat 8 thermal infrared data, while the economic impact was estimated based on data on work force structure and work productivity in Cluj-Napoca derived from the data released by Eurostat, National Bank of Romania, and National Institute of Statistics. The results indicate that the intensity and spatial extension of surface urban heat island could be governed by the magnitude of the heat wave event, but due to the low number of satellite images available, we should consider this information only as preliminary results. Thermal infrared remote sensing has proven to be a very efficient method to study surface urban heat island, due to the fact that the synoptic conditions associated with heat wave events usually favor cloud free image. The resolution of the OLI_TIRS sensor provided good results for a mid-extension city, but the low revisiting time is still a drawback. The potential economic loss was calculated for the working days during heat waves and the estimated loss reached more than 2.5 mil. EUR for each heat wave day at city scale, cumulating more than 38 mil. EUR for the three cases considered.     

The urban heat island of a city in an arid zone: the case of Eilat, Israel

Summary This study presents the results of a preliminary research that was conducted in the city of Eilat, located in an extreme hot and arid zone on the northern coast of the Red Sea. The purpose was to analyse the characteristics of the local urban heat island (UHI). Diurnal pre-dawn and early-afternoon measurements were taken in winter and summer weather conditions on three separate occasions for two consecutive years. The results show the development of a moderate UHI located around the most intensive area of human activity; the city business centre and dense hotel belt. The UHI is more significant at midday during the summer period, while early morning inversions in winter have a weakening effect on the UHI intensity. It was found that the topography and wind regime have a dominant effect on the location and intensity of the UHI, while the sea has a very marginal effect. Due to the UHI influences on the spatial distribution of the heat stress in the city, it is suggested that further applied UHI research should be focused on the summer period.     

The Role of Ocean Dynamics in the Cross-equatorial Energy Transport under a Thermal Forcing in the Southern Ocean

Under external heating forcing in the Southern Ocean, climate models project anomalous northward atmosphere heat transport (AHT) across the equator, accompanied by a southward shift of the intertropical convergence zone (ITCZ). Comparison between a fully coupled and a slab ocean model shows that the inclusion of active ocean dynamics tends to partition the cross-equatorial energy transport and significantly reduce the ITCZ shift response by a factor of 10, a finding which supports previous studies. To understand how ocean dynamics damps the ITCZ's response to an imposed thermal heating in the Southern Ocean, we examine the ocean heat transport (OHT) and ocean circulation responses in a set of fully coupled experiments. Results show that both the Indo-Pacific and the Atlantic contribute to transport energy across the equator mainly through its Eulerian-mean component. However, different from previous studies that linked the changes in OHT to the changes in the wind-driven subtropical cells or the Atlantic meridional overturning circulation (AMOC), our results show that the cross-equatorial OHT anomaly is due to a broad clockwise overturning circulation anomaly below the subtropical cells (approximately bounded by the 5℃ to 20℃ isotherms and 50°S to 10°N). Further elimination of the wind-driven component, conducted by prescribing the climatological wind stress in the Southern Ocean heat perturbation experiments, leads to little change in OHT, suggesting that the OHT response is predominantly thermohaline-driven by air-sea thermal interactions.     

Counteracting urban climate change: adaptation measures and their effect on thermal comfort

Cities represent thermal load areas compared with their surrounding environments. Due to climate change, summer heat events will increase. Therefore, mitigation and adaptation are needed. In this study, meteorological measurements in various local climate zones were performed to demonstrate the influence of evaporation surfaces and other factors on thermal comfort, as determined by the physiologically equivalent temperature (PET). Furthermore, a quantification of the thermal effects of several adaptation measures and varying meteorological parameters was made using model simulations (ENVI-met) in an inner-city neighborhood (Oberhausen, Germany). The results show that the most effective adaptation measure was increased wind speed (maximal 15 K PET reduction). Moreover, vegetation areas show greater PET reductions by the combination of shading and evapotranspiration than water surfaces. The creation of park areas with sufficient water supply and tall, isolated, shade-providing trees that allow for adequate ventilation can be recommended for planning.     

A bioclimatic design methodology for urban outdoor spaces

Summary The development of a bioclimatic urban design methodology is described. The cluster thermal time constant (CTTC) model for predicting street-level urban air temperature variations is coupled with the wind-profile power law and the index of thermal stress (ITS.) for human comfort. TheCTTC model and the power law produce the diurnal air temperature and wind speed variations in various canyonlike urban forms. The thermal comfort requirements for lightly-dressed, moderately-walking/seated persons in the outdoor space in summer are then obtained using the ITS. model. The proposed methodology enables a first-order assessment of the climatic implications of different features of the physical structure of the city such as street orientation, canyon height-to-width ratio, building density, and street shading. The application of the proposed methodology is demonstrated for Tel Aviv.With 9 Figures