scholarly journals Assessment of Outdoor Thermal Comfort in Serbia’s Urban Environments during Different Seasons

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1084
Author(s):  
Milica Lukić ◽  
Dejan Filipović ◽  
Milica Pecelj ◽  
Ljiljana Crnogorac ◽  
Bogdan Lukić ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Urban Areas ◽  
Meteorological Data ◽  
Weather Conditions ◽  
Urban Environments ◽  
Outdoor Thermal Comfort ◽  
Strong Impact ◽  
Data Set ◽  
Different Seasons ◽  
Novi Sad

The urban microclimate is gradually changing due to climate change, extreme weather conditions, urbanization, and the heat island effect. In such an altered environment, outdoor thermal comfort can have a strong impact on public health and quality of life in urban areas. In this study, three main urban areas in Serbia were selected: Belgrade (Central Serbia), Novi Sad (Northern Serbia), and Niš (Southern Serbia). The focus was on the temporal assessment of OTC, using the UTCI over a period of 20 years (1999–2018) during different seasons. The main aim is the general estimation of the OTC of Belgrade, Novi Sad, and Niš, in order to gain better insight into the bioclimatic condition, current trends and anomalies that have occurred. The analysis was conducted based on an hourly (7 h, 14 h, and 21 h CET) and “day by day” meteorological data set. Findings show the presence of a growing trend in seasonal UTCI anomalies, especially during summer and spring. In addition, there is a notable increase in the number of days above the defined UTCI thresholds for each season. Average annual UTCIs values also show a positive, rising trend, ranging from 0.50 °C to 1.33 °C. The most significant deviations from the average UTCI values, both seasonal and annual, were recorded in 2000, 2007, 2012, 2015, 2017, and 2018.

scholarly journals Sky View Factors from Synthetic Fisheye Photos for Thermal Comfort Routing—A Case Study in Phoenix, Arizona

2017 ◽  
Vol 2 (1) ◽  
pp. 19-30 ◽  
Author(s):  
Ariane Middel ◽  
Jonas Lukasczyk ◽  
Ross Maciejewski
Keyword(s):  
Thermal Comfort ◽  
Urban Form ◽  
Urban Areas ◽  
Meteorological Data ◽  
Routing Algorithm ◽  
Google Earth ◽  
Urban Environments ◽  
Tree Planting ◽  
Outdoor Thermal Comfort ◽  
View Factor

The Sky View Factor (SVF) is a dimension-reduced representation of urban form and one of the major variables in radiation models that estimate outdoor thermal comfort. Common ways of retrieving SVFs in urban environments include capturing fisheye photographs or creating a digital 3D city or elevation model of the environment. Such techniques have previously been limited due to a lack of imagery or lack of full scale detailed models of urban areas. We developed a web based tool that automatically generates synthetic hemispherical fisheye views from Google Earth at arbitrary spatial resolution and calculates the corresponding SVFs through equiangular projection. SVF results were validated using Google Maps Street View and compared to results from other SVF calculation tools. We generated 5-meter resolution SVF maps for two neighborhoods in Phoenix, Arizona to illustrate fine-scale variations of intra-urban horizon limitations due to urban form and vegetation. To demonstrate the utility of our synthetic fisheye approach for heat stress applications, we automated a radiation model to generate outdoor thermal comfort maps for Arizona State University’s Tempe campus for a hot summer day using synthetic fisheye photos and on-site meteorological data. Model output was tested against mobile transect measurements of the six-directional radiant flux density. Based on the thermal comfort maps, we implemented a pedestrian routing algorithm that is optimized for distance and thermal comfort preferences. Our synthetic fisheye approach can help planners assess urban design and tree planting strategies to maximize thermal comfort outcomes and can support heat hazard mitigation in urban areas.

scholarly journals CREATING MULTI-TEMPORAL MAPS OF URBAN ENVIRONMENTS FOR IMPROVED LOCALIZATION OF AUTONOMOUS VEHICLES

2020 ◽  
Vol XLIII-B2-2020 ◽  
pp. 317-323
Author(s):  
J. Schachtschneider ◽  
C. Brenner
Keyword(s):  
Urban Areas ◽  
Autonomous Vehicles ◽  
Weather Conditions ◽  
Point Clouds ◽  
Urban Environments ◽  
Seasonal Effects ◽  
Data Set ◽  
Multi Temporal ◽  
One Year

Abstract. The development of automated and autonomous vehicles requires highly accurate long-term maps of the environment. Urban areas contain a large number of dynamic objects which change over time. Since a permanent observation of the environment is impossible and there will always be a first time visit of an unknown or changed area, a map of an urban environment needs to model such dynamics.In this work, we use LiDAR point clouds from a large long term measurement campaign to investigate temporal changes. The data set was recorded along a 20 km route in Hannover, Germany with a Mobile Mapping System over a period of one year in bi-weekly measurements. The data set covers a variety of different urban objects and areas, weather conditions and seasons. Based on this data set, we show how scene and seasonal effects influence the measurement likelihood, and that multi-temporal maps lead to the best positioning results.

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.

scholarly journals Biomimicry-Based Strategies for Urban Heat Island Mitigation: A Numerical Case Study under Tropical Climate

Biomimetics ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 48
Author(s):  
Kevin Araque ◽  
Paola Palacios ◽  
Dafni Mora ◽  
Miguel Chen Austin
Keyword(s):  
Thermal Comfort ◽  
Urban Heat Island ◽  
Urban Areas ◽  
Outdoor Thermal Comfort ◽  
Base Case ◽  
Heat Island ◽  
Urban Heat ◽  
Historical Heritage ◽  
Pet Index ◽  
Radiant Temperature

In recent years, demographic growth has caused cities to expand their urban areas, increasing the risk of overheating, creating insurmountable microclimatic conditions within the urban area, which is why studies have been carried out on the urban heat island effect (UHI) and its mitigation. Therefore, this research aims to evaluate the cooling potential in the application of strategies based on biomimicry for the microclimate in a historical heritage city of Panama. For this, three case studies (base case, case 1, and case 2) of outdoor thermal comfort were evaluated, in which the Envi-met software was used to emulate and evaluate the thermal performance of these strategies during March (highest temperature month) and October (rainier month). The strategies used were extracted from the contrast of zebra skin, human skin, evaporative cooling, and ant skin. The results showed a reduction of 2.8 °C in the air temperature at 11:00, the radiant temperature decreased by 2.2 °C, and the PET index managed to reduce the thermal comfort indicator among its categories. The importance of thinking based on biomimicry in sustainable strategies is concluded; although significant changes were obtained, high risks of discomfort persist due to the layout and proximity of the building.

scholarly journals The most problematic variable in the course of human-biometeorological comfort assessment — the mean radiant temperature

2011 ◽  
Vol 3 (1) ◽  
Author(s):  
Noémi Kántor ◽  
János Unger
Keyword(s):  
Thermal Comfort ◽  
Short Wave ◽  
Urban Environments ◽  
Outdoor Thermal Comfort ◽  
Radiation Environment ◽  
Wave Radiation ◽  
Mean Radiant Temperature ◽  
Radiation Fluxes ◽  
The Mean ◽  
Radiant Temperature

AbstractThis paper gives a review on the topic of the mean radiant temperature Tmrt, the most important parameter influencing outdoor thermal comfort during sunny conditions. Tmrt summarizes all short wave and long wave radiation fluxes reaching the human body, which can be very complex (variable in spatial and also in temporal manner) in urban settings. Thermal comfort researchers and urban planners need easy and sound methodological approaches to assess Tmrt. After the basics of the Tmrt calculation some of the methods suitable for obtaining Tmrt also in urban environments will be presented.. Two of the discussed methods are based on instruments which measure the radiation fluxes integral (globe thermometer, pyranometer-pyrgeometer combination), and three of the methods are based on modelling the radiation environment with PC software (RayMan, ENVI-met and SOLWEIG).

scholarly journals Geochemical perspectives from a new aerosol chemical mass closure

2007 ◽  
Vol 7 (6) ◽  
pp. 1657-1670 ◽  
Author(s):  
B. Guinot ◽  
H. Cachier ◽  
K. Oikonomou
Keyword(s):  
Urban Areas ◽  
Conversion Factor ◽  
Major Ions ◽  
Fine Fraction ◽  
Coarse Fraction ◽  
Urban Environments ◽  
Data Set ◽  
K Value ◽  
Mass Closure ◽  
Chemical Mass Closure

Abstract. The aerosol chemical mass closure is revisited and a simple and inexpensive methodology is proposed. This methodology relies on data obtained for aerosol mass, and concentration of the major ions and the two main carbon components, the organic carbon (OC) and the black carbon (BC). Atmospheric particles are separated into coarse (AD>2 μm) and fine (AD<2 μm) fractions and are treated separately. For the coarse fraction the carbonaceous component is minor and assumption is made for the conversion factor k of OC-to-POM (Particulate Organic Matter) which is fixed to the value of 1.8 accounting for secondary species. The coarse soluble calcium is shown to display a correlation (regression coefficient f, y axis intercept b) with the missing mass. Conversely, the fine fraction is dominated by organic species and assumption is made for dust which is assumed to have the same f factor as the coarse mode dust. The fine mode mass obtained from chemical analyses is then adjusted to the actual weighed mass by tuning the k conversion factor. The k coefficient is kept different in the two modes due to the expected different origins of the organic particles. Using the f and k coefficient obtained from the data set, the mass closure is reached for each individual sample with an undetermined fraction less than 10%. The procedure has been applied to different urban and peri-urban environments in Europe and in Beijing and its efficiency and uncertainties on f and k values are discussed. The f and k coefficients are shown to offer consistent geochemical indications on aerosol origin and transformations. f allows to retrieve dust mass and its value accounting for Ca abundance in dust at the site of investigation may serve as an indicator of dust origin and aerosol interactions with anthropogenic acids. f values were found to vary in the 0.08–0.12 range in European urban areas, and a broader range in Beijing (0.01–0.16). As expected, k appears to be a relevant proxy for particle origin and ageing and varies in the 1.4–1.8 range. For Beijing, k exhibits high values of about 1.7 in winter and summer. Winter values suggest that fresh coal aerosol might be responsible for such a high k value, which was not taken into account in previous works.

scholarly journals Optimization of building form and its fenestration in response to microclimate conditions of an urban area

2020 ◽  
Vol 172 ◽  
pp. 19002
Author(s):  
Kavan Javanroodi ◽  
Vahid M. Nik ◽  
Yuchen Yang
Keyword(s):  
Thermal Comfort ◽  
Urban Area ◽  
Urban Areas ◽  
Energy Demand ◽  
High Performance ◽  
Weather Conditions ◽  
Climate Data ◽  
Heating And Cooling ◽  
Building Form ◽  
Microclimate Conditions

Designing building form in urban areas is a complicated process that demands considering a high number of influencing parameters. On the other hand, there has been an increasing trend to design highly fenestrated building envelopes for office buildings to induce higher levels of natural lighting into the workspace. This paper presents a novel optimization framework to design high-performance building form and fenestration configuration considering the impacts of urban microclimate in typical and extreme weather conditions during a thirty-year period of climate data (2010-2039). In this regard, based on the introduced technique and algorithm, the annual energy demand and thermal comfort of over 8008 eligible form combinations with eight different fenestration configurations and seven different building orientation angels were analysed in a detailed urban area to find optimal design solutions in response to microclimate conditions. Results showed that adopting the framework, annual heating, and cooling demand can be reduced by 21% and 38% while maintaining thermal comfort by taking design-based decisions at the early stages of design.

scholarly journals Modelling hourly evapotranspiration in urban environments with SCOPE using open remote sensing and meteorological data

2021 ◽  
Author(s):  
Alby Duarte Rocha ◽  
Stenka Vulova ◽  
Christiaan van der Tol ◽  
Michael Förster ◽  
Birgit Kleinschmit
Keyword(s):  
Remote Sensing ◽  
Land Surface ◽  
Urban Areas ◽  
Meteorological Data ◽  
Urban Environments ◽  
Coefficient Of Determination ◽  
World Population ◽  
Model Errors ◽  
Vegetation Fraction ◽  
Process Based Models

Abstract. Evapotranspiration (ET) is a fundamental variable to assess water balance and urban heat island effect. ET is deeply dependent on the land cover as it derives mainly from the processes of soil evaporation and plant transpiration. The majority of well-known process-based models based on the Penman-Monteith equation focus on the atmospheric interfaces (e.g. radiation, temperature and humidity), lacking explicit input parameters to describe the land surface. The model Soil-Canopy-Observation of Photosynthesis and Energy fluxes (SCOPE) accounts for a broad range of surface-atmosphere interactions to predict ET. However, like most modelling approaches, SCOPE assumes a homogeneous vegetated landscape to estimate ET. Urban environments are highly fragmented, exhibiting a blend of pervious and impervious anthropogenic surfaces. Whereas, high-resolution remote sensing (RS) and detailed GIS information to characterise land surfaces is usually available for major cities. Data describing land surface properties were used in this study to develop a method to correct bias in ET predictions caused by the assumption of homogeneous vegetation by process-based models. Two urban sites equipped with eddy flux towers presenting different levels of vegetation fraction and imperviousness located in Berlin, Germany, were used as study cases. The correction factor for urban environments has increased model accuracy significantly, reducing the relative bias in ET predictions from 0.74 to −0.001 and 2.20 to −0.13 for the two sites, respectively, considering the SCOPE model using RS data. Model errors (i.e. RMSE) were also considerably reduced in both sites, from 0.061 to 0.026 and 0.100 to 0.021, while the coefficient of determination (R2) remained similar after the correction, 0.82 and 0.47, respectively. This study presents a novel method to predict hourly urban ET using freely available RS and meteorological data, independently from the flux tower measurements. The presented method can support actions to mitigate climate change in urban areas, where most the world population lives.

scholarly journals Vegetation and microclimate in open urban areas. Cuiabá, Mato Grosso - Brazil

2020 ◽  
Vol 7 (3) ◽  
pp. 1089-1099
Author(s):  
Maria Corette Pasa ◽  
Lucas Henrique Vieira Lenci ◽  
Nhaára Da Vila Pereira ◽  
Rosenil Antonia de Oliveira Miranda
Keyword(s):  
Relative Humidity ◽  
Thermal Comfort ◽  
Urban Areas ◽  
Modern Science ◽  
Well Being ◽  
Urban Environments ◽  
Forest Fragment ◽  
Open Spaces ◽  
Mato Grosso ◽  
Significant Difference

The influence of vegetation on the reduction of heat in open urban environments by providing a milder and more pleasant microclimate is highlighted in modern science. The objective of this study was to evaluate the trend of microclimatic variables and thermal comfort, in the Federal University of Mato Grosso - UFMT campus, in open spaces (forest fragment, cerrado and paved) with and without afforestation. Three collection points were selected in open spaces (wooded and without afforestation) at the UFMT campus in Cuiabá. To record the data, we used the Alloet Thermohigrometer mini-markers, model TA-318 with 0.1%. The collections took place in May of 2018, period that begins the local winter. The microclimatic variables such as air temperature, relative humidity (%), wind speed, ultraviolet index and chance of rain were analyzed daily from 09:00 to 17:00 for 15 days. The results highlight the importance of the shade provided by the tree vegetation in the forest fragment, which revealed a significant difference for the thermal comfort in relation to the other sample points and without afforestation. The microclimatic parameters present variations of the temperature and relative humidity of the air at the points allocated, with emphasis on the thermal comfort sensation for the wooded area. The research also suggests new scientific investments in studies on urban micro-climates as a way to stimulate and raise awareness of the importance of vegetation in thermal comfort, which can directly reflect the health and well-being of people in general. 

scholarly journals Spatially Resolved Analysis of Urban Thermal Environments Based on a Three-Dimensional Sampling Algorithm and UAV-Based Radiometric Measurements

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4847
Author(s):  
Daniel Rüdisser ◽  
Tobias Weiss ◽  
Lukas Unger
Keyword(s):  
Thermal Comfort ◽  
Urban Areas ◽  
Global Radiation ◽  
Three Dimensional ◽  
Evaluation Process ◽  
Outdoor Thermal Comfort ◽  
Wave Radiation ◽  
Imaging Data ◽  
Three Dimensional Model ◽  
Spatially Resolved

A new method and workflow to assess outdoor thermal comfort and thermal stress in urban areas is developed. The new methodology is applied to a case of an urban quarter in the city of Graz. The method recognises the significance of detailed and accurate spatially resolved determination of mean radiant temperatures taking into account all relevant radiative components, comprising thermal radiation, as well as global radiation. The method relies on radiometric imaging data that are mapped onto a three-dimensional model. The image data are acquired by means of drones (UAVs) equipped with multispectral and thermographic cameras to capture short- and long-wave radiation. Pre-existing city models and a Monte Carlo raytracing algorithm to perform anisotropic sampling based on a 3D model with human topology are used to determine local radiation temperatures with high spatial resolution. Along with spot measurements carried out on the ground simultaneously, the spatially resolved and three-dimensionally determined mean radiation temperatures are used to calculate thermal comfort indicator maps using UTCI and PMV calculation. Additional ground measurements are further used to validate the detection, as well as the entire evaluation process.

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