Assessment of biometeorological conditions in Eastern Mediterranean City Adana, Turkey from past to the future.

Human bioclimatic comfort (HBC) is an important subject of climatology in the field of physical geography. Human bioclimatic comfort (HBC) is the feeling of satisfied and comfortable within the ambient atmospheric thermal environment. Earth climate system has been exposed to changes from the beginning, but since 19th century human - induced factors have contributed to these changes. HBC is the combined effect of atmospheric conditions and affected by all the changes in them. Turkey is among the countries in Mediterranean region, expected to develop higher vulnerabilities to the (bio) climate hazards. Therefore, a Mediterranean city in the south of the country, Adana, was chosen as the study area. HBC assessment was made for the past (1961 - 1990), present (1991 - 2022), near (2030 - 2060) and distant future (2070 - 2100) using hourly - data from the official meteorology station between 1961 and 2022, daily data of the climate model scenarios (Representative Concentration Pathway - RCP4.5 and RCP8.5) and Physiological Equivalent Temperature (PET) index, the Rayman model and Geographic Information Systems in the spatial distribution of HBC conditions. The analysis showed that the prevalence of "cold" and "cool" stresses has decreased while that of "hot" and "very hot" stresses has increased from the past to the present in Adana. It is predicted that present conditions will continue in the near and distant future, all comfort ranges will increase to the following warm range and the ideal period for HBC conditions will be the winter season. In order to reduce the adverse HBC conditions in cities due to climate change by creating climate resilient, sustainable and healthy cities, urban design and planning principles should be followed from a geographical point of view.

Characteristic of bioclimatic conditions in Poland based on Physiologically Equivalent Temperature.

The aim of the study was to characterise bioclimatic conditions in Poland in the times of progressing warming. This type of research permits the verification whether the progressing climate warming also translates into a change in bioclimatic conditions. This study was based on data obtained for the period 1966-2021 from 37 synoptic stations located in Poland. All the data series were uniform and obtained from the data base of the Institute of Meteorology and Water Management-National Research Institute (IMGW-PIB). The study revealed high variability of bioclimatic conditions in Poland both in spatial and in temporal terms. The lowest mean annual PET values were recorded in the north and north-east of the country and the highest in the south-west of Poland. The study revealed changes in the frequency of occurrence of days with cold and heat stress, as well as days with no thermal stress. The most intensive changes were determined for days with cold stress. A decrease in the number of days in this category translated into an increase in the number of days with no thermal stress and days with heat stress.

Biometeorological conditions during cold spells in south-east Poland and west Ukraine.

The aim of this research is to analyze the biometeorological conditions, based on the Physiologically Equivalent Temperature (PET) thermal index, during cold spells (CSs) in south-east Poland and west Ukraine during the years 1966-2021. The research shows a high variability of the occurrence of CSs in the study period and a clear increase in the frequency and total duration of CSs in the east of the study area. The number of CSs in the analyzed years varies from 6 cases in the west (in Katowice) to 34 in the east of the study area (in Shepetivka). The total duration of CSs varied from 26 days (in Raciborz and Katowice) to 166 days (in Rivne). At the majority of stations, CSs occurred most frequently in the first two decades (1966/1967-1975/1976, 1976/1977-1985/986) and in the last full decade (2006/2007-2015/2016). The average PET values at 12:00 UTC during CSs decreased eastwards throughout the study domain and were generally lower than -20.0 °C in the west of Ukraine, while in south-east Poland varied between -18.1 and -20.0 °C. At 40% of stations across the study domain, the lowest average PET values were recorded during a cold spell in January 1987, with PET values varying from -28.0 °C in Chernivtsi to -12.7 °C in Yaremche. The longest or one of the longest spells in most stations (in 77% of stations across the study domain) was the cold spell of 2012 and characterized by mean PET values ranging from -25.4 °C in Rivne to -19.5 °C in Zakopane.

[Health protection and climate change require ambitious limit values for air pollutants in Europe : Opinion on the revision of the Directive on Air Quality and Clean Air for Europe of the Environmental Public Health commission of the Robert Koch Institute and the Federal Environment Agency]. / Gesundheitsschutz und Klimawandel erfordern ambitionierte Grenzwerte für Luftschadstoffe in Europa : Stellungnahme zur Revision der Richtlinie über Luftqualität und saubere Luft für Europa der Kommission Environmental Public Health des Robert Koch-Instituts und des Umweltbundesamtes.

Based on scientific findings, the World Health Organization (WHO) has recommended stricter guideline values for air quality in 2021. Significant reductions in the annual mean values of particulate matter (particle size 2.5 µm or smaller, PM2.5) and long-term exposure to nitrogen dioxide (NO2) and ozone (O3) were put forward. The risk of mortality already increases above the WHO guideline values, as shown in studies investigating low concentrations of air pollutants. In Germany, the 2021 WHO guideline values for PM2.5 and NO2 were clearly exceeded in 2022.In this position paper we give the following recommendations for the European Air Quality Directive: (1) set binding limit values according to WHO 2021, (2) apply the limit values to the whole of Europe, (3) continue and expand the established country-based monitoring networks, (4) expand air quality measurements for ultrafine particles and soot particles, and (5) link air pollution control and climate protection measures.Stricter limits for air pollutants require societal and political changes in areas such as mobility, energy use and generation, and urban and spatial planning. Implementation according to WHO 2021 would lead to a net economic benefit of 38 billion euros per year.Ambitious limit values for air pollutants also have an impact on climate change mitigation and its health impacts. The Environmental Public Health commission concludes that more ambitious limit values are crucial to enable effective health protection in Germany and calls for air pollutant limit values in line with the 2021 WHO recommendations to become binding in Europe.

Analysis of air temperature dynamics in the "local climate zones" of Novi Sad (Serbia) based on long-term database from an urban meteorological network.

A comprehensive analysis of air temperature (Ta) dynamics in "local climate zones" (LCZs) of Novi Sad (Serbia) was based on measurements from 17 stations during 3 years. Hourly changes of Ta, cooling rates (CR), heating rates (HR), and urban heat island (UHI) intensity were assessed on seasonal and annual level and during heat wave (HW) and cold wave (CW) periods. Substantial differences are observed for minimum (Tmin) and mean temperatures (Tmean) between LCZs. Two-phase nocturnal cooling was recognized with the first cooling phase characterized by intensive LCZ dependent cooling starting at 1-3 h before sunset and lasting until 3-4 h after sunset. The second cooling phase lasts until sunrise and is characterized by less intensive and LCZ nondependent cooling. The most intensive cooling (CRpeak) was observed in first cooling phase of HW and ranged from - 1.6 °C h-1 in street canyon (LCZ 2) to - 3.9 °C h-1 in forest (LCZ A). Furthermore, a new cooling indicator (CRtotal) was introduced. Due to cooling differences, the most intensive UHI of 5.5 °C was noticed between LCZs 2 and A at sunset + 1 h during HW. Two-phase diurnal heating was also recognized in LCZs with the first heating phase characterized by intensive LCZ dependent heating starting at sunrise and lasting until 4-7 h afterwards. The most intensive heating (HRpeak) ranged from 2.0 °C h-1 in street canyon to 3.0 °C h-1 in industrial area (LCZ 8) during HW. The second heating phase lasts until sunset and is characterized by less intensive heating and smaller HR differences between LCZs.

A Low-Cost Sensor Network for Real-Time Thermal Stress Monitoring and Communication in Occupational Contexts.

The MoBiMet (Mobile Biometeorology System) is a low-cost device for thermal comfort monitoring, designed for long-term deployment in indoor or semi-outdoor occupational contexts. It measures air temperature, humidity, globe temperature, brightness temperature, light intensity, and wind, and is capable of calculating thermal indices (e.g., physiologically equivalent temperature (PET)) on site. It visualizes its data on an integrated display and sends them continuously to a server, where web-based visualizations are available in real-time. Data from many MoBiMets deployed in real occupational settings were used to demonstrate their suitability for large-scale and continued monitoring of thermal comfort in various contexts (industrial, commercial, offices, agricultural). This article describes the design and the performance of the MoBiMet. Alternative methods to determine mean radiant temperature (Tmrt) using a light intensity sensor and a contactless infrared thermopile were tested next to a custom-made black globe thermometer. Performance was assessed by comparing the MoBiMet to an independent mid-cost thermal comfort sensor. It was demonstrated that networked MoBiMets can detect differences of thermal comfort at different workplaces within the same building, and between workplaces in different companies in the same city. The MoBiMets can capture spatial and temporal differences of thermal comfort over the diurnal cycle, as demonstrated in offices with different stories and with different solar irradiances in a single high-rise building. The strongest sustained heat stress was recorded at industrial workplaces with heavy machinery.

The influence of foehn winds on the incidence of severe injuries in southern Bavaria - an analysis of the TraumaRegister DGU®.

BACKGROUND: Foehn describes a wind which occurs in areas with close proximity to mountains. The presence of foehn wind is associated with worsening health conditions. This study analyzes the correlation between a foehn typical circulation and the incidence for suffering a severe trauma. METHODS: This is a retrospective, multicentre observational register study. The years from 2013 to 2016 were analyzed for the presence of foehn winds. A logistic regression analysis with the number of daily admitted trauma patients as the primary target value was performed in dependence of foehn winds. Southern Bavaria is a typical foehn wind region. Individuals were treated in 37 hospitals of Southern Bavaria which participate in the TraumaRegister DGU®, an international register that includes all severe trauma patients, mainly in Germany. We analyzed patients with an Injury Severity Score (ISS) of at least nine with admission to intensive care units or prior death in the emergency room. RESULTS: 6215 patients were enrolled in this study. A foehn-typical circulation was present on 65 days (4.5%). 301 patients (5%) suffered a trauma with an ISS ≥ 9 on a foehn day. The mean ISS was 20.2 (9-75). On average, 4.3 patients (0-15 patients) were admitted on a daily basis due to a severe trauma. The multivariate regression analysis revealed a daily increase of 0.87 individuals (p = 0.004; 95% CI 0.23-1.47) on foehn days. During spring 1.07 patients (p = < 0.001; 95% CI 0.72-1.42), in summer 1.98 patients (p = < 0.001; 95% CI 1.63-2.32), in fall 0.63 (p = < 0.001; 95% CI 0.28-0.97) and on Saturdays, 0.59 patients (p = < 0.001; 95% CI 0.24-0.93) were additionally admitted due to severe trauma. CONCLUSION: Foehn winds are significantly associated with severe trauma in trauma centers of the TraumaNetzwerk DGU®.

[Thermal stress of urban dwellers during heat waves using the example of Freiburg (Breisgau)]. / Thermische Belastung von Bewohnern in Städten bei Hitzewellen am Beispiel von Freiburg (Breisgau).

BACKGROUND: As a result of climate change, people are increasingly affected by heat and the negative health effects of heat. Air temperature is often used as a measurement. However, in order to characterize the effects of heat on humans, other factors must be considered in addition to air temperature. OBJECTIVES: The aim of this paper is to characterize the thermal stress of urban dwellers by means of the perceived temperature during heat waves, compare it with rural dwellers, and highlight differences from air temperature. MATERIALS AND METHODS: Data from the year 2019 are used from two different German Weather Service (DWD) stations located within the city of Freiburg im Breisgau, Germany, and its surroundings (Freiburg Airport). Air temperature as well as other meteorological elements were taken to calculate the perceived temperature by means of the Klima-Michel model. Additionally, days with heat warnings as well as nightly indoor temperatures from the heat health warning system are presented. RESULTS: The perceived temperature exceeds the air temperature during heat waves by up to 10 °C. The classic heat-island effect is particularly evident in the difference in the nightly air temperature while the difference in the daily air temperature is small. In the case of perceived temperature, the difference is significantly higher not only at night but also during the day. CONCLUSIONS: In order to quantify negative impacts, not only the knowledge of air temperature is required, but also other factors that describe and control the thermal stress on humans. Urban-rural differences in air temperature and perceived temperature enable heat quantification. Adaptation measures taking into account the more intense conditions in cities are necessary.

[Estimation of heat-related deaths in Germany between 2001 and 2015]. / Schätzung hitzebedingter Todesfälle in Deutschland zwischen 2001 und 2015.

BACKGROUND: During the summers of 2003 and 2015, heat was found to be the cause of a substantial number of deaths in Germany. Until now, estimates for the total number of heat-related deaths were only available regionally in Germany. For the summer of 2003, an analysis for Baden-Württemberg was extrapolated to the whole of Germany. OBJECTIVES: Our analysis tries to prove a stable statistical relationship between heat and mortality and to use this to quantify the number of heat-related deaths in Germany between the years 2001 and 2015. MATERIALS AND METHODS: By fitting a nonlinear statistical model, we estimated exposure-response curves that describe the influence of heat on the mortality rate. The performance of different indicators for heat stress was compared. RESULTS: The comparison of the different indicators for heat showed that the weekly mean temperature was most useful to explain the course of the weekly mortality during the summer. The relation between mortality rate and weekly mean temperature varied between age groups and regions in Germany (north, middle, south). The age groups (75-84) and (85+) were most affected by heat. The highest number of heat-related deaths was 7600 (95% CI 5500-9900), found for the summer 2003, followed by 6200 (4000; 8000) in the summer 2006 and 6100 (4000; 8300) in the summer 2015. CONCLUSIONS: We could show that even in weekly data on mortality, a clear influence of heat could be identified. A national surveillance of mortality that allows real-time monitoring would be desirable.

[Relevance of Heat Health Actions Plans for Preventive Public Health in Germany]. / Bedeutung von Hitzeaktionspläne für den präventiven Gesundheitsschutz in Deutschland.

BACKGROUND: Heat waves are among the extreme weather events and represent a growing health hazard for the population in Europe. According to the current climate studies, the probability of an increase and intensification of heat waves has been increasing for years. Particularly affected by exposure to unusually high heat are people whose organism is already weakened by age or illness. As the share of senior citizens in Germany continues to rise as a result of demographic change, the health effects of heat waves are gaining in importance. OBJECTIVE: Heat-induced morbidity and mortality can be effectively countered by information provision and timely initiation of preventive measures. The heat wave of the summer of 2003, which killed around 70000 people across Europe, led to the establishment of national heat warning systems and / or hot weather plans in much of Europe. In Germany, the heat warning system of the German Weather Service was set up nationwide in 2005. Thus, a 2-stage warning process can be comprehensively and timely inform people of an imminent heat wave, whereupon appropriate preventive measures can be initiated. In addition, it is recommended to establish a heat action plan which, in addition to heat warning, also takes into account comprehensive health intervention measures. MATERIALS AND METHODS: This article outlines the background, significance and structure of a heat action plan according to the World Health Organization (WHO). This is based on the guidance document prepared in 2008 and the supplementary documents of the years 2009 and 2011. RESULTS AND DISCUSSION: In order to ensure sustainable protection against heat-related health hazards, the World Health Organization (WHO) recommends the introduction of a national heat action plan for its Member States. There are fundamental differences between a heat warning system and a heat action plan. While the warning of a brief heat period is the central task of the heat warning system, the heat action plan follows an integrative approach that combines short, medium and long-term health protection measures within a common framework.

Assessment of human thermal perception in the hot-humid climate of Dar es Salaam, Tanzania.

Dar es Salaam, Tanzania, is a typical African city along the Indian Ocean coast, and therefore an important urban area to examine human thermal perception in the hot-humid tropical climate. Earlier research on human bioclimate at Dar es Salaam indicated that heat stress prevails during the hot season from October to March, peaking between December and February, particularly the early afternoons. In order to assess the human thermal perception and adaptation, two popular places, one at an urban park and another at a beach environment, were selected and questionnaire surveys were conducted in August-September 2013 and January 2014, concurrently with local micro-meteorological measurements at survey locations. The thermal conditions were quantified in terms of the thermal index of the physiologically equivalent temperature (PET) using the micro-scale climate model RayMan. The thermal comfort range of human thermal comfort and the local thermal adaptive capacity were determined in respect to the thermal index by binning thermal sensation votes. The thermal comfort range was found to be well above that in temperate climates at about 23-31 °C of PET. The study could significantly contribute to urban planning in Dar es Salaam and other coastal cities in the tropics.

Comparison of selected approaches for urban roughness determination based on voronoi cells.

Wind speed is reduced above urban areas due to their high aerodynamic roughness. This not only holds for above the urban canopy. The local vertical wind profile is modified. Aerodynamic roughness (both roughness length and displacement height) therefore is relevant for many fields within human biometeorology, e.g. for the identification of ventilation paths, the concentration and dispersion of air pollutants at street level or to simulate wind speed and direction in urban environments and everything depending on them. Roughness, thus, also shows strong influence on human thermal comfort. Currently, roughness parameters are mostly estimated using classifications. However, such classifications only provide limited assessment of roughness in urban areas. In order to calculate spatially resolved roughness on the micro-scale, three different approaches were implemented in the SkyHelios model. For all of them, the urban area is divided into reference areas for each of the obstacles using a voronoi diagram. The three approaches are based on building and [+one of them also on] vegetation (trees and forests) data. They were compared for the city of Stuttgart, Germany. Results show that the approach after Bottema and Mestayer (J Wind Eng Ind Aerodyn 74-76:163-173 1998) on the spatial basis of a voronoi diagram provides the most plausible results.

Implementation of human thermal comfort information in Köppen-Geiger climate classification-the example of China.

Köppen-Geiger climate classification (KGC) is accepted and applied worldwide. The climatic parameters utilised in KGC, however, cannot indicate human thermal comfort (HTC) conditions or air humidity (AH) conditions directly, because they are originally based on climatic effects on vegetation, instead of that on human body directly. In addition, HTC is driven by meteorological parameters together. Thus, the objective of this study is to preliminarily implement the HTC information and the AH information in KGC. Physiologically equivalent temperature (PET) has been chosen as the HTC index, and vapour pressure (VP) is for the quantification of AH conditions. In this preliminary study, 12 Chinese cities in total have been taken into account as the assumed representatives of 11 climate types. Basic meteorological data of each city with 3-h resolution in 2000-2012 has been analysed. RayMan model has been applied to calculate PET within the same time period. Each climate type has been described by frequencies of PET and frequencies of VP. For example, the Aw (Sanya) has the most frequent occurrence of thermally stressful conditions compared to other climate types: PET in 22 % points in time of the year was above 35 °C. The driest AH conditions existed in Dwc (Lhasa) and Dfb (Urumqi) with VP rarely above 18 hPa in the wettest month. Implementation of the HTC information and the additional AH information in each climate type of KGC can be helpful for the topics of human health, energy consumption, tourism, as well as urban planning.

Quantification of thermal bioclimate for the management of urban design in Mediterranean climate of Barcelona, Spain.

In order to contribute to the sustainability of the outdoor environment, knowledge about the urban thermal bioclimate should be transferred into climatic guidelines for planning. The general framework of this study responds to the need of analyzing thermal bioclimate in Mediterranean climate regions and its influence as an urban design factor. The paper analyzes the background of the urban climate and thermal bioclimate conditions in Barcelona (Spain), through the effect of shade conditions and wind speed variations. Simulations of shade and wind speed variations were performed to evaluate changes in thermal bioclimate due to modifications in urban morphology. Air temperature, relative humidity, wind speed, and solar radiation for the period from January, 2001 to January, 2015 were used to calculate physiologically equivalent temperature (PET) using the RayMan model. The results demonstrate that shade is the most important strategy to improve urban microclimatic conditions. In Barcelona, human thermal comfort conditions can be improved by shade and wind speed increase in terms of PET above 23 °C and by a wind speed decrease for thresholds of PET below 18 °C. Heat stress situations can be mitigated by shade and wind speed increase in conditions above 35 and 45 °C, respectively. The results of the study are an important contribution for urban planners, due to their possibilities and potential for the description of microclimatic conditions in Mediterranean climate regions. The knowledge is useful for improved human thermal comfort conditions, from the suitable configuration of urban form and architecture.

Quantification and assessment of heat and cold waves in Novi Sad, Northern Serbia.

Physiologically equivalent temperature (PET) has been applied to the analysis of heat and cold waves and human thermal conditions in Novi Sad, Serbia. A series of daily minimum and maximum air temperature, relative humidity, wind, and cloud cover was used to calculate PET for the investigated period 1949-2012. The heat and cold wave analysis was carried out on days with PET values exceeding defined thresholds. Additionally, the acclimatization approach was introduced to evaluate human adaptation to interannual thermal perception. Trend analysis has revealed the presence of increasing trend in summer PET anomalies, number of days above defined threshold, number of heat waves, and average duration of heat waves per year since 1981. Moreover, winter PET anomaly as well as the number of days below certain threshold and number of cold waves per year until 1980 was decreasing, but the decrease was not statistically significant. The highest number of heat waves during summer was registered in the last two decades, but also in the first decade of the investigated period. On the other hand, the number of cold waves during six decades is quite similar and the differences are very small.

Effects of ventilation behaviour on indoor heat load based on test reference years.

Since 2003, most European countries established heat health warning systems to alert the population to heat load. Heat health warning systems are based on predicted meteorological conditions outdoors. But the majority of the European population spends a substantial amount of time indoors, and indoor thermal conditions can differ substantially from outdoor conditions. The German Meteorological Service (Deutscher Wetterdienst, DWD) extended the existing heat health warning system (HHWS) with a thermal building simulation model to consider heat load indoors. In this study, the thermal building simulation model is used to simulate a standardized building representing a modern nursing home, because elderly and sick people are most sensitive to heat stress. Different types of natural ventilation were simulated. Based on current and future test reference years, changes in the future heat load indoors were analyzed. Results show differences between the various ventilation options and the possibility to minimize the thermal heat stress during summer by using an appropriate ventilation method. Nighttime ventilation for indoor thermal comfort is most important. A fully opened window at nighttime and the 2-h ventilation in the morning and evening are more sufficient to avoid heat stress than a tilted window at nighttime and the 1-h ventilation in the morning and the evening. Especially the ventilation in the morning seems to be effective to keep the heat load indoors low. Comparing the results for the current and the future test reference years, an increase of heat stress on all ventilation types can be recognized.

Human thermal comfort conditions and urban planning in hot-humid climates-The case of Cuba.

Climate regional characteristics, urban environmental conditions, and outdoors thermal comfort requirements of residents are important for urban planning. Basic studies of urban microclimate can provide information and useful resources to predict and improve thermal conditions in hot-humid climatic regions. The paper analyzes the thermal bioclimate and its influence as urban design factor in Cuba, using Physiologically Equivalent Temperature (PET). Simulations of wind speed variations and shade conditions were performed to quantify changes in thermal bioclimate due to possible modifications in urban morphology. Climate data from Havana, Camagüey, and Santiago of Cuba for the period 2001 to 2012 were used to calculate PET with the RayMan model. The results show that changes in meteorological parameters influence the urban microclimate, and consequently modify the thermal conditions in outdoors spaces. Shade is the predominant strategy to improve urban microclimate with more significant benefits in terms of PET higher than 30 °C. For climatic regions such as the analyzed ones, human thermal comfort can be improved by a wind speed modification for thresholds of PET above 30 °C, and by a wind speed decreases in conditions below 26 °C. The improvement of human thermal conditions is crucial for urban sustainability. On this regards, our study is a contribution for urban designers, due to the possibility of taking advantage of results for improving microclimatic conditions based on urban forms. The results may enable urban planners to create spaces that people prefer to visit, and also are usable in the reconfiguration of cities.

Sport events and climate for visitors--the case of FIFA World Cup in Qatar 2022.

The effect of weather on sport events is not well studied. It requires special attention if the event is taking place at a time and place with extreme weather situations. For the world soccer championship in Qatar (Doha 2022), human biometeorological analysis has been performed in order to identify the time of the year that is most suitable in terms of thermal comfort for visitors attending the event. The analysis is based on thermal indices like Physiologically Equivalent Temperature (PET). The results show that this kind of event may be not appropriate for visitors, if it is placed during months with extreme conditions. For Doha, this is the period from May to September, when conditions during a large majority of hours of the day cause strong heat stress for the visitors. A more appropriate time would be the months November to February, when thermally comfortable conditions are much more frequent. The methods applied here can quantify the thermal conditions and show limitations and possibilities for specific events and locations.

Comparison of different methods for the assessment of the urban heat island in Stuttgart, Germany.

This study of the urban heat island (UHI) aims to support planning authorities by going beyond the traditional way of urban heat island studies. Therefore, air temperature as well as the physiologically equivalent temperature (PET) were applied to take into account the effect of the thermal atmosphere on city dwellers. The analysis of the urban heat island phenomenon of Stuttgart, Germany, includes a long-term frequency analysis using data of four urban and one rural meteorological stations. A (high resolution map) of the UHI intensity and PET was created using stepwise multiple linear regression based on data of car traverses as well as spatial data. The mapped conditions were classified according to the long-term frequency analysis. Regarding climate change, the need for adaptation measures as urban greening is obvious. Therefore, a spatial analysis of quantification of two scenarios of a chosen study area was done by the application of a micro-scale model. The nocturnal UHI of Stuttgart is during 15 % stronger than 4 K in the city center during summer when daytime heat stress occurs during 40 %. A typical summer condition is mapped using statistical approach to point out the most strained areas in Stuttgart center and west. According to the model results, the increase in number of trees in a chosen area (Olga hospital) can decrease PET by 0.5 K at 22:00 CET but by maximum 27 K at 14:00 CET.

A note on the evolution of the daily pattern of thermal comfort-related micrometeorological parameters in small urban sites in Athens.

Studies on human thermal comfort in urban areas typically quantify and assess the influence of the atmospheric parameters studying the values and their patterns of the selected index or parameter. In this paper, the interpretation tools are the first derivative of the selected parameters (∆Parameter/∆t) and the violin plots. Using these tools, the effect of sites' configuration on thermal conditions was investigated. Both derivatives and violin plots indicated the ability of vegetation to act as a buffer to the rapid changes of air temperature, mean radiant temperature, and the physiologically equivalent temperature (PET). The study is focused on the "thermal extreme" seasons of winter (December, January, and February) and summer (June, July, and August) during a 3-year period of measurements in five selected sites under calm wind and sunny conditions. According to the results, the absence of vegetation leads to high derivative values whereas the existence of dense vegetation tends to keep the parameters' values relatively low, especially under hot weather conditions.