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Heat stress negatively influences human health and performance, and leading to lower efficiency in daily activities. The present study sought to examine the relationship between UTCI, other heat indices (SET, PET, PMV, PPD, and WBGT), and environmental parameters. Daily data, encompassing a 12 month period in 2016 (from 6 a.m. to 9 p.m. for each da...
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... A total of 248 sample datasets were collected from 56 meteorological stations, and UTCI was calculated based on the meteorological factors (Fig. 2a). UTCI, based on the concept of equivalent temperature, represents the temperature that would evoke the same physiological response in an individual as they would experience in the real environment under standardized reference conditions (Zare et al., 2018). This index effectively reflects human sensations of the thermal environment. ...
Achieving urban cooling from a sustainable perspective requires strategic planning of building area (S) and height (H). However, there is a lack of human thermal stress assessment and it is not clear how to optimize the layout of building spatial morphology to alleviate human thermal stress. We simulated the Universal Thermal Climate Index (UTCI), characterizing high spatial resolution human comfort, by machine learning, and analyzed the relationship between building spatial morphology and UTCI to determine the feasible layout of building spatial morphology. Our findings indicated that the study area experienced poor human thermal comfort, with residents facing high thermal stress (average UTCI of 36 °C). Zoning analysis revealed that an increase in S resulted in a simultaneous rise in UTCI, while an increase in H leaded to a trend of UTCI that initially rose and then declined. An increase in S-rating had a more pronounced impact on elevating UTCI (0.29 °C on average) compared to an increase in H-rating (0.11 °C on average). To maintain UTCI within the UTCI threshold that characterized ideal human comfort, a trade-off relationship between S and H should be maintained, which was further influenced by the stationary and plunge intervals in their relationship curve. The findings have the potential to provide valuable insights for policymakers and stakeholders, aiding them in making informed decisions in urban planning to alleviate human thermal stress.
... Notably, the combination of high humidity and temperature during extreme heat events can exacerbate human thermal discomfort and, in severe cases, pose life-threatening risks . The thermal comfort index, which incorporates other meteorological parameters (e.g., humidity) and human factors, offers a more comprehensive understanding of the heat stresses experienced by the public compared to LST or observed temperatures (Buzan et al., 2015;Zare et al., 2018). Thermal comfort indices, rather than temperature indices, should be utilized to evaluate public thermal discomfort during hot weather. ...
Climate change-intensified urban warming has brought attention to urban parks’ spatial allocation due to their cooling effects. However, conventional accessibility assessments of park cooling effects consider temperature and size, overlooking critical factors such as thermal comfort and supply and demand differences in thermal environments, which more accurately represent public thermal stress. We developed a multimode Gaussian-based Huff three-step floating catchment area method based on thermal stress differences between population locations and parks. This method integrates thermal comfort and cellular population data to assess the spatial mismatch between the supply and demand for park cooling services in Shanghai. Our findings show that most central and developing urban areas have excellent park cooling accessibility. However, considering population demand, central Shanghai requires improved internal park planning to enhance the cooling supply. In contrast, Shanghai's suburban areas exhibit significant supply-demand imbalances, especially in the south and southeast; they require an enhanced cooling supply through planning interventions. Incorporating thermal comfort differences into calculations shifts the highest per capita cooling supply area from the outer suburbs to the suburbs, substantially reducing areas with high demand but low supply. Our novel analytical approach to assessing park cooling accessibility can assist policymakers in developing precise climate adaptation strategies.
... UTCI was chosen as an indicator of OTC, which was determined for all simulated scenarios using Biomet 5.0.3 [40]. UTCI is based on a multi-node model of thermoregulation that considers air temperature, relative humidity, solar radiation, and wind speed [70,71,72]. UTCI is considered a universal index that is applicable across climates, seasons, and spatial scales [73] and that shows strong correlations to other thermal indices, including Standard Equivalent Temperature (SET), PET, or wet-bulb globe temperature [12,72,74]. ...
... UTCI is based on a multi-node model of thermoregulation that considers air temperature, relative humidity, solar radiation, and wind speed [70,71,72]. UTCI is considered a universal index that is applicable across climates, seasons, and spatial scales [73] and that shows strong correlations to other thermal indices, including Standard Equivalent Temperature (SET), PET, or wet-bulb globe temperature [12,72,74]. UTCI is chosen in favor of PET due to its independence of a person's characteristics such as age or gender [71]. ...
The health of urban populations is increasingly at risk due to the amplification and chronification of urban heat stress by climate change. This is particularly true for urban environments in humid tropical climates, including many cities in Southeast Asia. It is also in these locations where increasing climatic risks may be exacerbated by urban growth, underscoring the need to develop effective mitigation strategies for strengthening urban resilience and supporting climate change adaptation. Conservation and widespread implementation of green infrastructure (GI) are regarded as one means to counter heat as a public health threat. However, for lower-income countries across Southeast Asia, such as Vietnam, knowledge gaps remain with respect to the effectiveness of greening interventions for heat mitigation. To address this gap, in the context of urban expansion in the humid tropical city of Huế, Vietnam, diurnal cooling potential and regulation of outdoor thermal comfort (OTC) within a wide, shallow street canyon were systematically assessed for selected elements of GI along a quantitative and qualitative dimension using ENVI-met. Tree-based interventions were found to be most effective, potentially decreasing UTCI by −1.9 K at the domain level. Although lower in magnitude, green verges and green facades were also found to contribute to OTC, with green verges decreasing UTCI by up to −1.7 K and green facades by up to −1.4 K locally. Potential synergistic cooling impacts were identified through a combination of GI elements. However, no scenario was found to decrease heat stress to zero or moderate levels. Substantially reducing heat stress may thus require further measures and a closer consideration of local morphological characteristics.
... It is a biometeorological index used for evaluating the health impacts of climate conditions related to heat (Di Napoli et al., 2018). The ERA5-HEAT UTCI has been widely evaluated and applied in different countries and regions (Antonescu et al., 2021;Brimicombe et al., 2021;Di Napoli et al., 2023;Kyaw et al., 2023;Miranda et al., 2023;Roffe et al., 2023;Shukla et al., 2022;Urban et al., 2021;and Zare et al., 2018). Miranda et al. (2023) analysed heat stress patterns in South America using ERA5-HEAT data from 1979 to 2020. ...
Nigeria's growing population faces an increasing heat burden with potential health risks. The Universal Thermal Comfort Index (UTCI) links outdoor conditions and human well-being but lacks comprehensive insitu data in developing regions like Nigeria. ERA5-HEAT reanalysis offers a solution with gridded UTCI and MRT data, but validation is crucial. Thus, this study evaluates the ERA5-HEAT UTCI against data from nine Nigerian weather stations and analysed the spatio-temporal patterns of heat stress trends. Results showed that ERA5-HEAT demonstrated reasonable statistical performance and captured the temporal characteristics and patterns of UTCI across Nigeria's climatic zones. Seasonal variations show heat stress levels from "slightly cold" to "moderate" at 0600 LST and "moderate" to "very strong" at 1500 LST. Geographical consistency exists within each season over the decades, with a critical "very strong" heat stress period during March-May. Additionally, there has been an increasing spatial expansion of areas experiencing higher heat stress levels across the country. Latitudinally, stable patterns exist across decades at 0600 LST for each season. Seasons show distinct UTCI values, and at 1500 LST, more variability and category transitions occur along latitudes. Furthermore, the results indicate significant positive trends and occasional non-significant negative trends over the 40-year period. Notably, during 0600 LST, the Guinea and Sahel regions exhibit relatively higher positive trends than the Sudan region in all seasons, whereas at 1500 LST, high positive trends are prominent in DJF and MAM seasons, indicating increased heat stress during peak seasons. These positive deviations in UTCI are associated with adverse effects on human health, including increased mortality rates.
... By integrating a gamut of meteorological variables, including temperature, humidity, wind speed, and solar radiation, the UTCI aptly characterizes comfort levels across varying environments (Park et al., 2014). As an advanced biometeorological index, the UTCI has objectivity in assessing the impact of the atmospheric milieu on the human organism (Zare et al., 2018). Currently, the UTCI is extensively employed in studies concerning short-term repercussions of atmospheric conditions on humans and urban bioclimatology and evaluations of the urban heat island effect (Hwang et al., 2022;Kyaw et al., 2023;. ...
Climate change has precipitated recurrent extreme events and emerged as an imposing global challenge, exerting profound and far-reaching impacts on both the environment and human existence. The Universal Thermal Climate Index (UTCI), serving as an important approach to human comfort assessment, plays a pivotal role in gauging how humans adapt to meteorological conditions and copes with thermal and cold stress. However, the existing UTCI datasets still grapple with limitations in terms of data availability, hindering their effective application across diverse domains. We have produced GloUTCI-M, a monthly UTCI dataset boasting global coverage and an extensive time series spanning March 2000 to October 2022, with a high spatial resolution of 1 km. This dataset is the product of a comprehensive approach leveraging multiple data sources and advanced machine learning models. Our findings underscored the superior predictive capabilities of CatBoost in forecasting the UTCI (mean absolute error, MAE = 0.747 °C; root mean square error, RMSE = 0.943 °C; and coefficient of determination, R2=0.994) when compared to machine learning models such as XGBoost and LightGBM. Utilizing GloUTCI-M, the geographical boundaries of cold stress and thermal stress areas at global scale were effectively delineated. Spanning 2001–2021, the mean annual global UTCI was recorded at 17.24 °C, with a pronounced upward trend. Countries like Russia and Brazil emerged as key contributors to the mean annual global UTCI increasing, while countries like China and India exerted a more inhibitory influence on this trend. Furthermore, in contrast to existing UTCI datasets, GloUTCI-M excelled at portraying UTCI distribution at finer spatial resolutions, augmenting data accuracy. This dataset can enhance our capacity to evaluate thermal stress experienced by humans, offering substantial prospects across a wide array of applications. GloUTCI-M is publicly available at https://doi.org/10.5281/zenodo.8310513 (Yang et al., 2023).
... This index describes the physiological comfort of the human body under specific meteorological conditions 96 . It is considered one of the most comprehensive indices as it takes into account not only air temperature but also humidity, wind, and radiation 97,98 . The Universal Thermal Climate Index is divided into ten categories, ranging from extreme cold stress to extreme heat stress. ...
... The Universal Thermal Climate Index is divided into ten categories, ranging from extreme cold stress to extreme heat stress. Values between 32°C and 38°C are associated with strong heat stress, while values between 38°C and 46°C are associated with very strong heat stress 98 . ...
The summer of 2022/23 in Argentina set a record with ten heatwaves. Here, we compare the synoptic and thermodynamic conditions of the four heatwaves with the largest spatial extent using ERA5 reanalysis data. All heatwaves were associated with mid-level anticyclonic anomalies but with different characteristics: three were quasi-stationary high-pressure systems, while one was transient. We also find that enhanced surface fluxes strongly influenced the daily temperature evolution. Furthermore, we perform an attribution exercise using the analogue technique to measure the contributions of atmospheric circulation, soil moisture, and climate change. For quasi-stationary events, the main contribution came from the circulation (up to 2 °C relative to random flow in the present climate). Conversely, the transient heatwave showed a stronger association with extreme soil moisture deficits, with an estimated increase of ~+1 °C relative to wetter conditions. Climate change has also increased the intensity of heatwaves by +0.5 to +1.2 °C relative to previous decades.
... The districts with the most intense heat stress are Kartal and Maltepe, according to the AT, HI, PET, and UTCI to the findings of previous studies (Blazejczyk et al. 2012;Zare et al. 2018). It has been determined that the sultriness effect of RH cannot be explained with a linear model since the diurnal relative humidity varies in an inverse cycle with the air temperature and thermal indices. ...
Thermal indices and thermal comfort maps have great importance in developing health-minded climate action strategies and livable urban layouts. Especially in cities where vulnerability to heatwaves is high, it is necessary to detect the most appropriate indicators for the regional characteristics and action planning with respect to thermal comfort. The aim of the study is to examine thermal indices as indicators of regional climate characteristics by relating to meteorological parameters and spatial features. Atmospheric variables including air temperature, wind speed, cloud cover, and relative humidity data were obtained from 30 meteorological stations located in districts having different climatic features. Heat stress levels for apparent temperature (AT), heat index (HI), wet bulb globe temperature (WBGT), physiological equivalent temperature (PET), universal thermal climate index (UTCI), and perceived temperature (PT) indices were calculated and associated with meteorological parameters. Thermal comfort maps have been created with the daily mean and maximum values of all indices. As a result, the meteorological parameters with the strongest correlation with all thermal indices are air temperature (T a ) with r = 0.89 ± 0.01 and mean radiant temperature (T mrt ) with r = 0.75 ± 0.16. The differences in thermal stress levels over the city have been distinctively observed in the AT max , PET max , and PT max maps, which are generated by the daily maximum values of the indices. Çatalca, where forests cover large areas compared to highly urbanized districts, has the lowest heat stress defined by all indices.
... PET has been applied in many countries, regions, localities or tourist resorts to evaluate human thermal comfort [59] for Valencia, Spain [60]; in Italian Alpine cities [61]; in Iran [62]; in Tehran [10]; for Xi'an, China etc.). Among the studies that use this index in the analysis of tourist potential from various natural or administrative entities around Romania, we can mention those belonging to Ref. [63] (for health tourism in Austria) [64]; (for the Vojvodina region of Serbia) [65][66][67][68][69]; (for regions, localities or the entire territory of Hungary) [48,70,71]; (for localities and islands in Greece) [72]; (for Odessa in Ukraine) [73,74]; (for Bursa and Uludag in Turkey) [74]; (for the territory of Austria and a number of resorts in the Austrian Alps) [20]; (for five resorts in the Moldova region of Romania) [75]; for the southern coastal region of the Caspian Sea. ...
The study analyzes with priority the bioclimatic conditions for tourist activities in two famoustourist areas in western Romania [(B ̆aile Felix–B ̆aile 1 Mai (BF_1 M) – Stˆana de Vale – Vl ̆adeasaand, respectively B ̆aile Herculane (BH) - Semenic], from the perspective of the potential of healthtourism and in the subsidiary of sports and camping tourism. Such researches are missing forwestern Romania. The main working tools in the evaluation of the tourist valences of the bio-climate include: the spatio-temporal analysis of the Physiologically Equivalent Temperature(PET) bioclimatic index, of the TCI climate-tourism index and of the climate-tourism schemes(CTIS). PET, TCI and CTIS were calculated and drawn up based on the daily data of the meteo-rological elements included in their calculation for the period 1961–2019. The bioclimate isanalyzed as an element of potential that can increase (through a better evaluation and knowl-edge) the attractiveness and sustainability of the health tourism in the already established resorts(BF_1 M, BH) and can develop sports and camping tourism in the direction of the two proposedaxes (Stˆana de Vale – Vl ̆adeasa și Semenic), with the decongestion of the resorts from the base themountains. The proposed objectives consist inmulti-criteria evaluation, promotion and sustain-able exploitation of the bioclimatic (and spa) resources of the six tourist destinations, but it alsoaims to increase the level of attention and information of all those interested, by promoting thebioclimatic and climate-tourism assets of complementary tourist destinations (Stˆana de Vale,Vl ̆adeasa, Semenic). The results obtained from the PET statistics show that between 25 and 39 %of the days of a year are comfortable, and the TCI statistics show that between 54 and 69 % of thedays are favorable for the practice of tourism. PET and TCI highlight that from mid-April to mid-October the bioclimatic conditions for health tourism are good at BF_1 M and BH and that, only inthe months of December–February the balneoclimatic procedures carried out outside the treat-ment bases are subject to climatic restrictions. Sports tourism has few temporal restrictions, andcamping tourism restricts its duration, from April to October in lowland resorts, to May toSeptember in mountain tourist destinations. CTIS shows that the resorts in western Romania havethe most favorable bioclimatic and climate-tourism conditions in Romania.
... The UTCI is expressed as the equivalent air temperature of a reference environment that elicits the same thermophysiological response from a reference person as the current environment. The reference environment is characterized by a relative humidity of 50%, negligible air velocity, and a T MRT equal to the air temperature [40][41][42][43][44][45]. Mathematically, this correlation can be expressed using Equation (10) [44]: ...
Citation: Fassbender, E.; Rott, J.; Hemmerle, C. Impacts of Photovoltaic Façades on the Urban Thermal Microclimate and Outdoor Thermal Abstract: Cities face the consequences of climate change, specifically the urban heat island (UHI) effect, which detrimentally affects human health. In this regard, deploying PV modules in urban locales prompts inquiry into the impact of energy-active building components on the adjacent thermal microclimate and human thermal comfort. A twofold simulation-based methodology addresses this subject: First, the implications of façade-integrated photovoltaics on the urban thermal microclimate are investigated using a case study in Munich, Germany. Secondly, a parameter study allows us to gain further insights into the relevance of several parameters on the microthermal impact. The simulation results show a daytime heating effect of photovoltaics on the mean radiant temperature of up to +5.47 K in summer and +6.72 K in winter. The increased mean radiant temperature leads to an elevation of the Universal Thermal Climate Index of up to +1.46 K in summer and +2.21 K in winter. During night-time, no increase in both metrics is identified-hence, nocturnal recovery as a key element for human health is not affected. Despite extended human exposure to thermal heat stress in summer, PV façades improve the annual outdoor thermal comfort autonomy by 0.91% due to lower cold stress in winter. The higher PV efficiencies and lower albedo of the reference building surface lower the heating effect. However, with the current efficiencies, PV façades consistently lead to heating of the surrounding thermal microclimate in summer and lower the outdoor thermal comfort.
... It is the air temperature of the reference environment which produces the same strain index value in comparison with the reference individual's response to the real environment. It is calculated by meteorological data like mean radiant temperature, relative humidity, wind speed and non-meteorological data like clothing thermal resistance and metabolic rate (Maqueda et al., 2018). UTCI is the main indicator used to evaluate thermal comfort in this study. ...
Road greening plays an important role in improving the thermal comfort of street canyons. Optimizing the landscape pattern of road green spaces is undoubtedly beneficial for better utilizing the effect of green spaces in improving thermal comfort in limite street greening area. Given that road greening can have completely different impacts on the thermal comfort of street canyons during the day and at night, this study attempts to explore how to optimize the landscape pattern of road greening to maximize its overall improvement in thermal comfort throughout the summer. This study takes a section of Guihua Road in Changsha, a city in central and southern China as an example, built a model based on the actural situation of the road, and based on this, constructs five optimization models to explore the effectiveness on improving thermal comfort. Research has found that optimizing the landscape pattern of road green spaces has a more significant effect on the daytime thermal comfort of street canyons, with the maximum difference in UTCI between models being 0.76 ℃. However, the maximum difference in UTCI between nighttime models is only 0.06 ℃. Therefore, fully utilizing the effect of plants can be effective to improve daytime thermal comfort of the street canyon. However, for the improvement of the nighttime thermal comfort of the street canyon, peolple should focus more on other measures like improving the ventilation and change the underlying surface materials.
