scholarly journals Long-term dynamics of urban thermal comfort in China’s four major capital cities across different climate zones

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8026 ◽  
Author(s):  
Yao Fu ◽  
Zhibin Ren ◽  
Qiuyan Yu ◽  
Xingyuan He ◽  
Lu Xiao ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Meteorological Data ◽  
Economic Activities ◽  
Physiological Equivalent Temperature ◽  
Rapid Urbanization ◽  
Climate Zones ◽  
Chinese Cities ◽  
Northern Cities

China has experienced intensive urbanization over the past decades. However, it is still unclear about the influence of urbanization on urban thermal comfort and how the effect varies with climate condition. Based on long-term daily meteorological data from 1990 to 2015 in four Chinese cities undergoing rapid urbanization, our study tried to detect the long-term dynamics of summer urban thermal comfort across different climate zones and analyze their relationships with urbanization. Our results showed that urbanization can increase urban temperature and decrease relative humidity and wind velocity. Urban thermal comfort and discomfort days also changed greatly, especially in Harbin, Northeast China from 1990 to 2015. However, such changes for different cities across different climate zones are inconsistent. Results also showed that urbanization especially for social economic activities can have a significant influence on the physiological Equivalent Temperature (PET). Compared with southern cities, the PET in northern cities such as Harbin and Changchun in this study is more sensitive to urbanization. These results reveal that the changing patterns of urban thermal comfort in Chinese cities under rapid urbanization, and help government take some effective measures to improve urban thermal environment.

scholarly journals Spatiotemporal patterns of urban thermal environment and comfort across 180 cities in summer under China’s rapid urbanization

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7424 ◽  
Author(s):  
Zhibin Ren ◽  
Yao Fu ◽  
Yunxia Du ◽  
Hongbo Zhao
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Urban Climate ◽  
Spatiotemporal Patterns ◽  
Physiological Equivalent Temperature ◽  
Rapid Urbanization ◽  
Northern Cities ◽  
Changing Patterns ◽  
Urbanization In China ◽  
Urban Thermal Environment

Background China is considered as the largest and most rapidly urbanizing nation in the world. However, possible changes of urban thermal environment and comfort under the rapid urbanization in China still remain poorly understood at a national scale. Methods Based on the data collected from 180 cities in 1990, 2005, and 2015 in China, the spatiotemporal patterns of urban thermal environment and comfort in summer and their relationships with urbanization variables were investigated in this study. Results Our results indicate that urban thermal environment has changed greatly during the 25 years. Furthermore, the changes of urban climate in different regions are inconsistent. The Physiological Equivalent Temperature (PET) at most cities (81%) in China increased from 1990 to 2015, which suggested that urban thermal comfort in China was also deteriorating during the 25 years. However, while the PET of some cities in China began to decrease from 2005 to 2015, there were still 33% of cities that had positive trends,which mainly located in North region. Urbanization resulted in a significant influence on urban climate. Compared to southern cities, northern cities were more sensitive to urbanization impact. The most important contribution to increasing of PET for urbanization variables is gross domestic product, followed by urban population. The analysis results reveal changing patterns of urban thermal comfort in China during summer season. It can help urban government and managers improve urban thermal environment and comfort.

scholarly journals Climate-Responsive Green-Space Design Inspired by Traditional Gardens: Microclimate and Human Thermal Comfort of Japanese Gardens

2021 ◽  
Vol 13 (5) ◽  
pp. 2736
Author(s):  
Lihua Cui ◽  
Christoph D. D. Rupprecht ◽  
Shozo Shibata
Keyword(s):  
Thermal Stress ◽  
Thermal Comfort ◽  
Thermal Environment ◽  
Meteorological Data ◽  
Green Spaces ◽  
Physiological Equivalent Temperature ◽  
Urban Green Spaces ◽  
Thermal Environments ◽  
Human Thermal Comfort ◽  
Japanese Gardens

Urban green spaces can provide relaxation, exercise, social interaction, and many other benefits for their communities, towns, and cities. However, green spaces in hot and humid regions risk being underutilized by residents unless thermal environments are designed to be sufficiently comfortable. Understanding what conditions are needed for comfortable outdoor spaces, particularly how people feel in regard to their thermal environment, is vital in designing spaces for public use. Traditional gardens are excellent examples of successful microclimate design from which we can learn, as they are developed over the generations through observation and modification. This study analyzed how Japanese gardens affect people’s thermal stress on extremely hot summer days. Meteorological data was collected in three Japanese gardens, and human thermal comfort was evaluated through physiological equivalent temperature (PET). Statistical analysis examined the relationship between spatial configurations of the gardens and thermal comfort. Our study revealed that Japanese gardens can efficiently ameliorate thermal stress. Spatial analysis showed that garden elements affect thermal comfort variously depending on time of the day and spatial distribution.

scholarly journals Outdoor Thermal Comfort at a University Campus: Studies from Personal and Long-Term Thermal History Perspectives

2020 ◽  
Vol 12 (21) ◽  
pp. 9284
Author(s):  
Jiao Xue ◽  
Xiao Hu ◽  
Shu Nuke Sani ◽  
Yuanyuan Wu ◽  
Xinyu Li ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Thermal History ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Cold Climate ◽  
Outdoor Thermal Comfort ◽  
Climate Index ◽  
University Campus ◽  
Winter Climate

Thermally comfortable outdoor spaces have contributed to high-quality urban living. In order to provide a further understanding of the influences of gender and long-term thermal history on outdoor thermal comfort, this study conducted field surveys at a university campus in Shanghai, China by carrying out microclimatic monitoring and subjective questionnaires from May to October, 2019. The analysis of collected data found that, during our survey, 57% of the occupants felt comfortable overall and 40–60% of them perceived the microclimate variables (air temperature, humidity, solar radiation, and wind speed) as “neutral”. The universal thermal climate index (UTCI) provided a better correlation with occupant thermal sensation than the physiologically equivalent temperature (PET). Females were more sensitive to the outdoor thermal environment than males. Older age led to lower thermal sensation, but the thermal sensitivities for age groups of <20, 20–50, and >50 were similar. Occupants who had resided in Shanghai for a longer period showed higher overall comfort rating and lower thermal sensation. Interviewees who came from hot summer and cold winter climate regions were less effected by the change of UTCI than those from severe cold or cold climate regions.

scholarly journals Evaluation of Thermal Comfort in the Traditional Bourgeoisie Houses in Beirut

2020 ◽  
Vol 3 (1) ◽  
pp. p1
Author(s):  
Jad Hammoud ◽  
Elise Abi Rached
Keyword(s):  
Thermal Comfort ◽  
Natural Ventilation ◽  
Heat Waves ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Residential Buildings ◽  
Ventilation System ◽  
Electricity Consumption ◽  
Comfort Level ◽  
Climate Zones

The increasing of energy demands has considerably increased the requirements for new and traditional buildings in different climate zones. Unprecedented heat waves have increased climate temperature, in particular, in moderate climate zones such as Lebanon. In Beirut, only the residential sector consumes 50% of total electricity consumption. HVAC (Heating, Ventilation and Air conditioning) systems are used to reach acceptable thermal comfort levels in the new residential buildings. In case of the traditional bourgeoisie houses in Beirut, there are no discussions about the use of HVAC systems to achieve the required thermal comfort level. Thus, to reach an acceptable thermal comfort level, these houses which already contain natural ventilation system shall adapt the modern thermal comfort requirements and thermal comfort strategies and technologies where their architectural features and existing materials condition the available solutions. In order to identify the best options within the possible intervention lines (envelopes, passive strategies, equipment, renewable energy systems), it is necessary to perceive the real performance of this type of houses. In this context, the article presents the results of the study of thermal performance and comfort in a three case studies located in Beirut. Detailed field data records collected are analyzed, with a view to identify the indoor thermal environment with respect to outdoor thermal environment in different seasons. Monitoring also included measurement of hygrothermal parameters and surveys of occupant thermal sensation.

scholarly journals A microclimate regulation study of Ficus altissima under winter conditions in lower subtropical China

2021 ◽  
Author(s):  
Wan Deng ◽  
Chunhua Xia ◽  
Jingyu Chen ◽  
Yanji Jiang
Keyword(s):  
Thermal Comfort ◽  
Functional Performance ◽  
Meteorological Data ◽  
Ground Cover ◽  
Vital Role ◽  
Tree Planting ◽  
Subtropical China ◽  
Physiological Equivalent Temperature ◽  
Area Index ◽  
Winter Conditions

Abstract As a widespread practice in urban landscape design, tree planting plays a vital role in improving the ecological environment and microclimate. This study obtained the physical, physiological, and meteorological data of Ficus altissima, a typical tree species in lower subtropical China, through field measurement, and analyzed its functional performance in microclimate regulation. Its results indicated that: (1) the leaf area index (LAI), sky visible factor (SVF), ground cover (GC), and other indicators of Ficus altissima had essential relationships with radiation attenuation, temperature, and humidity regulation under winter conditions in lower subtropical China; (2) there were significant differences in leaf surface temperature and transpiration between east, west, north, and south during daytime; and, (3) thermal comfort represented by physiological equivalent temperature(PET)in the shade could be expressed as functions of solar radiation (SR), mean radiation temperature (MRT), air temperature (Ta), air humidity (RH), globe temperature (Tg), and wind speed (V). Based on these results, the following were the suggestions: firstly, Ficus altissima with higher LAI values should be selected for planting; secondly, trees must be planted on the east side of the site should solitary planting be undertaken to obtain maximum thermal comfort; and finally, activities under the canopy of Ficus altissima should be prioritized at 11:00–16:00 during winter.

scholarly journals Sea Breeze Front and Outdoor Thermal Comfort during Summer in Northeastern Brazil

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1013
Author(s):  
Max Anjos ◽  
António Lopes ◽  
Andrews José de Lucena ◽  
Francisco Mendonça
Keyword(s):  
Heat Stress ◽  
Thermal Comfort ◽  
Meteorological Data ◽  
Sea Breeze ◽  
Weather Conditions ◽  
Northeastern Brazil ◽  
Outdoor Thermal Comfort ◽  
Physiological Equivalent Temperature ◽  
Local Climate ◽  
Local Climate Zones

Characterizing the behaviour of the sea breeze phenomenon is the foremost factor in the reduction in the heat stress and the achievement of the pleasant environment in coastal cities globally. However, this seminal study shows that the Sea Breeze Front (SBF) development can be related to an increase in outdoor thermal discomfort in a northeastern Brazilian city during summer. We explored the relationship between SBF and thermal comfort conditions using in situ meteorological observations, the SBF identification method, local climate zones (LCZs) classification, and the Physiological Equivalent Temperature (PET) thermal comfort index. SBF days and Non-SBF days were characterized in terms of weather conditions, combining meteorological data and technical bulletins. SBF days included hot and sunny days associated with the centre of the Upper Tropospheric Cyclonic Vortices (UTCV). In contrast, Non-SBF days were observed in UTCV’s periphery because of cloudy sky and rainfall. The results showed that the mean temperature and PET in the SBF days were 2.0 °C and 3.8 °C higher, respectively, compared to Non-SBF days in all LCZ sites. The highest PET, of 40.0 °C, was found on SBF days. Our findings suggest that SBF development could be an aggravating factor for increasing heat stress of the people living in the northeastern coast of the Brazilian city, after SBF passage.

A tropical field study on outdoor bioclimatic comfort of people with different thermal histories

2020 ◽  
pp. 1420326X2095123
Author(s):  
Chunjing Shang ◽  
Yanxi Chen ◽  
Jianhong Cai ◽  
Zhongjun Zhang
Keyword(s):  
Thermal Comfort ◽  
Field Study ◽  
Thermal History ◽  
Environmental Changes ◽  
Thermal Sensation ◽  
Physiological Equivalent Temperature ◽  
Cold Regions ◽  
Bioclimatic Comfort ◽  
Thermal Histories

Several studies reported that the long-term thermal history of the human body affects its thermal comfort and preferences. We conducted a tropical field study in Sanya city, China; 1512 questionnaires were collected from tourists. The tourists had five thermal histories associated with five different climate regions (cold, severely cold, hot summer, cold winter, hot summer and warm winter and temperate regions). Our results showed that the human body's long-term thermal history had distinct influences on their thermal sensation, thermal comfort and preferences at their destination. Greater difference in a subject's thermal history from that of the tourist destination showed greater difference in the bioclimatic comfort and thermal preference. The neutral physiological equivalent temperature (nPET) of tourists with thermal histories in the severely cold and cold regions was 25.6°C and 25.9°C, respectively. The nPET was 1.4°C and 1.7°C higher than that of the temperate regions, respectively. The relationship between thermal acceptability vote and thermal comfort vote showed that the tourists with thermal histories in the severely cold and cold regions were more sensitive to environmental changes than those with histories from the other regions.

Long-term dynamics of thermal comfort in the territories of the Krasnoyarsk region climate belts

2021 ◽  
pp. 38-45
Author(s):  
Rofail Salykhovich Rakhmanov ◽  
Denis Alekseevich Narutdinov ◽  
Elena Sergeevna Bogomolova ◽  
Natalya Nikolaevna Potekhina ◽  
Sergey Aleksandrovich Razgulin
Keyword(s):  
Risk Assessment ◽  
General Population ◽  
Health Risk ◽  
Thermal Comfort ◽  
Effective Temperature ◽  
Climate Zones ◽  
Climate Zone ◽  
Subarctic Climate ◽  
Continental Climate

Health risk assessment in the general population in different climate zones of the Krasnoyarsk Territory by the equivalent effective temperature (EET). The average monthly EET according to Missenard was calculated, their dynamics and health risk were assessed within two periods of determining climate norms for the last 10 years of each period (1961–1990 and 1991–2020). Within the period of 1991–2020 compared with the previous period in the subarctic climate in the summer months, EET had positive values (in opposition of 2 months in 1961–1990), increased in April by 7.87 °С (p = 0.0004), in June by 5.56 °С (p = 0.019) and October by 3.2 °С (p = 0.038); in continental climate zone — in April at 5.23 °С (p = 0.0001), in June at 3.88 °С (p = 0.0009) and in August at 1.32 °С (p = 0.023). Living conditions of the population have become more favorable, the nature of the health risk has changed. In the subarctic climate, the changes in uncomfortable conditions occurred according to the criteria of «frostbite threat» — «cold» (5 months against 6 months in the first period), «cool» — «moderately cool» (2 months against 3 months), «comfort, moderately warm. «In the continental climate zone, the changes were noted according to the criteria of «moderately warm» — «very cool» (7 months against 5 months). In both climate zones, positive changes have caused a decrease in health risk according to two criteria («the threat of frostbite»; «very cold»); there was a shift from the risk assessed as «cold»towards «comfort, moderately warm».

scholarly journals Effects of Urban Configuration on Human Thermal Conditions in a Typical Tropical African Coastal City

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Emmanuel Lubango Ndetto ◽  
Andreas Matzarakis
Keyword(s):  
Thermal Comfort ◽  
Climate Model ◽  
Meteorological Data ◽  
Urban Climate ◽  
Thermal Conditions ◽  
Urban Street ◽  
Coastal City ◽  
Human Thermal Conditions ◽  
Comfort Parameters

A long-term simulation of urban climate was done using the easily available long-term meteorological data from a nearby synoptic station in a tropical coastal city of Dar es Salaam, Tanzania. The study aimed at determining the effects of buildings’ height and street orientations on human thermal conditions at pedestrian level. The urban configuration was represented by a typical urban street and a small urban park near the seaside. The simulations were conducted in the microscale applied climate model of RayMan, and results were interpreted in terms of the thermal comfort parameters of mean radiant (Tmrt) and physiologically equivalent (PET) temperatures. PET values, high as 34°C, are observed to prevail during the afternoons especially in the east-west oriented streets, and buildings’ height of 5 m has less effect on the thermal comfort. The optimal reduction ofTmrtand PET values for pedestrians was observed on the nearly north-south reoriented streets and with increased buildings’ height especially close to 100 m. Likewise, buildings close to the park enhance comfort conditions in the park through additional shadow. The study provides design implications and management of open spaces like urban parks in cities for the sake of improving thermal comfort conditions for pedestrians.

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