scholarly journals Effect of Vegetation Structure on Urban Climate Mitigation

2020 ◽  
Vol 23 (2) ◽  
pp. 60-65
Author(s):  
Zdenka Rózová ◽  
Ján Supuka ◽  
Ján Klein ◽  
Matej Jasenka ◽  
Attila Tóth ◽  
...  

AbstractVegetation formations are an important component in the urban structure, as they perform a wide range of ecosystem services there. The climate modification to improve the environmental and residential quality of the city is one of the important functions. The paper presents the results of the microclimate assessment in the chosen localities of Nitra town, Slovakia, with an emphasis on the stage and differences in air temperature and relative humidity. The climate elements were measured at 7 spatially different sites (sites A to G), each of them at two comparative sites, vegetation stand and open area. The largest average air temperature difference between the vegetation stand and the non-vegetation area was 1.2 °C at the locality D. The largest air temperature difference in the vegetation stands was measured between the street space (site E) and the city park (F), reaching 2.3–2.5 °C. The relative air humidity reached the highest differences between the park (locality F) and the street space (G) measured at 3:00–8:00. These reached 19.6% to 24.4% with higher relative humidity in the popular city park. The highest differences between the compared habitats were measured at locality G and averaged 9.6% at 04:00 – 07:00 in a preference to a tree canopy. The research results confirmed the importance of the vegetation structures in the process of mitigating the urban climate extremes and the environmental quality improving.

2018 ◽  
Vol 40 ◽  
pp. 37
Author(s):  
Thiago D'Orazio Joaquim ◽  
Jonathan Willian Zangeski Novais ◽  
Levi Pires de Andrade ◽  
Karyna De Andrade Carvalho Rosseti ◽  
Maricéia Tatiana Vilani ◽  
...  

Climate in urban areas, not under the effect of vegetation, was investigated and its benefits were observed in both vegetated and un-vegetated areas. The objective of this research was to model the air temperature and relative humidity using the Software ENVI-met® in an urban park in Cuiabá. The development of the methodology of this work involved two phases: survey (microclimate) and simulation. The microclimate survey was conducted through a mobile transect, for the periods of January 2014 to March 2014 (hot/wet) and July 2015 to September 2015 (hot/dry). The simulation was developed using ENVI-met® software during these two periods of the year. Generally maximizing the parameters, the ENVI-met® model for microclimate varied in the presence of too much vegetation. Simulations showed an increase in temperature and relative humidity in areas not surrounding the Mãe Bonifacia City Park, and this was particularly apparent in areas laid with asphalt and concrete. Vegetated parks play an important role in how hot climate thermoregulatory agents behave in the city of Cuiabá and the surrounding region.


Author(s):  
Josh Foster ◽  
James W. Smallcombe ◽  
Simon Hodder ◽  
Ollie Jay ◽  
Andreas D. Flouris ◽  
...  

Abstract Increasing air movement can alleviate or exacerbate occupational heat strain, but the impact is not well defined across a wide range of hot environments, with different clothing levels. Therefore, we combined a large empirical study with a physical model of human heat transfer to determine the climates where increased air movement (with electric fans) provides effective body cooling. The model allowed us to generate practical advice using a high-resolution matrix of temperature and humidity. The empirical study involved a total of 300 1-h work trials in a variety of environments (35, 40, 45, and 50 °C, with 20 up to 80% relative humidity) with and without simulated wind (3.5 vs 0.2 m∙s−1), and wearing either minimal clothing or a full body work coverall. Our data provides compelling evidence that the impact of fans is strongly determined by air temperature and humidity. When air temperature is ≥ 35 °C, fans are ineffective and potentially harmful when relative humidity is below 50%. Our simulated data also show the climates where high wind/fans are beneficial or harmful, considering heat acclimation, age, and wind speed. Using unified weather indices, the impact of air movement is well captured by the universal thermal climate index, but not by wet-bulb globe temperature and aspirated wet-bulb temperature. Overall, the data from this study can inform new guidance for major public and occupational health agencies, potentially maintaining health and productivity in a warming climate.


2021 ◽  
pp. 1-42
Author(s):  
Emmanuel Panagiotakis ◽  
Dionysia Kolokotsa ◽  
Nektarios Chrysoulakis

The present paper aims to study the impact of Nature Based Solutions (NBS) on the urban environment. The Surface Urban Energy and Water balance Scheme (SUEWS) is used to quantify the impact of NBS in the city of Heraklion, Crete, Greece, a densely built urban area. Local meteorological data and data from an Eddy Covariance flux tower installed in the city center are used for the model simulation and evaluation. Five different scenarios are tested by replacing the city’s roofs and pavements with green infrastructure, i.e., trees and grass, and water bodies. The NBS impact evaluation is based on the changes of air temperature above 2m from the ground, relative humidity and energy fluxes. A decrease of the air temperature is revealed with the highest reduction (2.3%) occurring when the pavements are replaced with grass for all scenarios. The reduction of the air temperature is followed by a decrease in turbulent sensible heat flux. For almost all cases, an increase of the relative humidity is noticed, accompanied by a considerable increase of the turbulent latent heat flux. Therefore, NBS in cities change the energy balance significantly and modify the urban environment for the citizens' benefit.


2015 ◽  
Vol 7 (5) ◽  
pp. 939
Author(s):  
Juliete Baraúna dos Santos

Foram obtidas medidas das variáveis meteorológicas temperatura do ar, umidade relativa do ar e velocidade do vento através da estação automática instalada em Arapiraca com a finalidade de monitorar as condições de tempo no município em diferentes períodos (época chuvosa e seca). Sendo utilizado o índice de desconforto (ID), o índice de desconforto de Kawamura (IDK), índice da temperatura efetiva (TE) e o índice de temperatura efetiva em função do vento (TEV). Os valores mais elevados dos índices que foram registrados para o período chuvoso, foram do índice id com aproximadamente 2,5 °C acima dos valores observados da temperatura do ar (em média 26,5 °C), caracterizando crescente desconforto para os indivíduos locais.  Para o período seco não houve registros de grandes variações entre os respectivos índices. E assim como no período chuvoso, os valores mais elevados no período seco foram do índice id, indicando nesse período também forte desconforto. Os valores obtidos estiveram condizentes com a literatura, sendo a sensação térmica mais preponderante durante o inverno. E, de acordo com as variações, em todo período de estudo (05 de maio de 2008 a 05 de maio de 2011) a população foi submetida aos alertas de atenção e muito cuidado, situação esta que pôde provocar fadiga ou cãibras, esgotamento e insolação nos casos de exposição prolongada e atividade física.      A B S T R A C T Measurements of meteorological variables air temperature, relative humidity and wind speed by automatic station installed in Arapiraca in order to monitor the weather conditions in the city in different periods (dry and rainy season) were obtained. Being used the discomfort index (ID), the discomfort index of Kawamura (IDK), index of effective temperature (TE) and the index of effective temperature as a function of wind (TEv). Higher index values ​​that were recorded for the rainy season, the index id were approximately 2.5 ° C above the observed values ​​of air temperature (average 26.5 ° C), indicating increasing discomfort for local individuals . For the dry period there were no reports of large variations between the respective indices. And just as the rainy season, the highest values ​​in the dry season were the index id, indicating that period also strong discomfort. The values ​​obtained were consistent with the literature, the most predominant wind chill during the winter. And, according to the variations in the study period (May 5, 2008 to 05 maio 2011) the population was subjected to warnings of attention and care, a situation that could cause fatigue or cramps, exhaustion and heat stroke in cases of prolonged exposure and physical activity.   Key-Words: Urban climate. Thermal comfort Human. Bioclimatic


2018 ◽  
Vol 10 (2) ◽  
pp. 1197-1205 ◽  
Author(s):  
Patrick R. Kormos ◽  
Danny G. Marks ◽  
Mark S. Seyfried ◽  
Scott C. Havens ◽  
Andrew Hedrick ◽  
...  

Abstract. Thirty-one years of spatially distributed air temperature, relative humidity, dew point temperature, precipitation amount, and precipitation phase data are presented for the Reynolds Creek Experimental Watershed, which is part of the Critical Zone Observatory network. The air temperature, relative humidity, and precipitation amount data are spatially distributed over a 10 m lidar-derived digital elevation model at an hourly time step using a detrended kriging algorithm. This 21 TB dataset covers a wide range of weather extremes in a mesoscale basin (238 km2) that encompasses the rain–snow transition zone and should find widespread application in earth science modeling communities. Spatial data allow for a more holistic analysis of basin means and elevation gradients, compared to weather station data measured at specific locations. Files are stored in the NetCDF file format, which allows for easy spatiotemporal averaging and/or subsetting. Data are made publicly available through an OPeNDAP-enabled THREDDS server hosted by Boise State University Libraries in support of the Reynolds Creek Critical Zone Observatory (https://doi.org/10.18122/B2B59V).


Author(s):  
Vicente De Paulo Rodrigues da Silva ◽  
Joel Silva Santos ◽  
Eduardo Rodrigues Viana de Lima ◽  
Romildo Morant de Holanda ◽  
Enio Pereira de Sousa ◽  
...  

Urbanization modifies the heat balance in urban areas and has negative effects on landscape, aesthetics, energy efficiency, human health and the inhabitants’ quality of life. This work evaluated future scenarios of bioclimatic conditions for João Pessoa, a humid tropical city in Northeast Brazil. The scenarios were determined based on trends in air temperature, relative humidity and wind speed for the time period from 1968 to 2015. The study was performed for two distinct periods of three months each (dry and wet seasons) using data from weather stations equipped with thermo-hygrometers and cup anemometers located in nine representative areas of the city. Trends in air temperature, relative humidity, wind speed, and effective temperature index (ET index) time series were evaluated using the Mann-Kendall test. Results indicated that the air temperature showed an increasing trend of 0.34°C/decade, whereas the relative humidity showed a decreasing trend of 0.49%/decade and the wind speed values ranged from 1.3 ms-1 to 3.80 ms-1. These trends are statistically significant according to the Mann-Kendall test (p<0.05). The air temperature increased between the 1980s and 2010s, which corresponds to a period of rapid urbanization of the city. Future environmental conditions in João Pessoa will be determined in accordance with the urbanization processes.


1975 ◽  
Vol 20 (2) ◽  
pp. 181-189 ◽  
Author(s):  
M. E. Castle ◽  
Thesca P. Thomas

SummaryThe intake of drinking water of lactating British Friesian cows in 14 herds with a total of 840 animals was measured monthly from November to April inclusive. The intake of food, the air temperature and relative humidity were also recorded. The herds which mainly contained autumn-calved cows were managed under controlled commercial conditions.The average daily intake of drinking water was 49·9 (range 20·1 to 87·1) kg/cow for animals yielding an average of 16·8 kg milk/day in an environment with a mean temperature of 8·2°C and a relative humidity of 84·8%. The amount of water drunk daily was positively and significantly related to the mean daily milk yield and the drymatter content of the ration, but not significantly related to either the mean air temperature or the relative humidity. The average intake of water was 3·70 kg per kg of dry matter consumed after subtracting the amount of water in the milk. On average, 40·0% of the total daily intake of water was drunk between 15·00 and 21·00 hr.Behaviour studies of 24 hr duration on five herds showed that drinking time ranged from 2·0 to 7·8 min/cow per day, and the rate of drinking varied from 4·5 to 14·9 kg/min.Recommendations are made for the provision of drinking water for dairy cows being offered a wide range of forages under modern conditions of housing.


2021 ◽  
Vol 283 ◽  
pp. 02032
Author(s):  
Song Hao

Urban street is an important form of urban space. It is the economic lifeline of the city, as well as the most public space that people use in daily life. City streets bears not only the flourished style of this region, but also embodies the unique style and taste of a city. Since China's reform and opening, economic development has maintaining a rapid growth momentum. The economic base determines the superstructure,so the scale of city population is facing a rapid expansion. The city is changing rapidly with the vigorous development of motor traffic. The traditional street space is faced with the situation of being nibbled away.Based on the concept of urban street and public space, this paper further analyzes the importance of paying attention to urban public life for achieving sustainable development, and then points out the importance of urban street space as an important carrier of public life in the context of rapid urbanization.By clarifying the important public value of urban streets, this paper draws the attention of a wide range of city government decision-makers and urban planners.


Tekstilec ◽  
2021 ◽  
Vol 64 (4) ◽  
pp. 298-304
Author(s):  
Ilda Kazani ◽  
◽  
Majlinda Hylli ◽  
Pellumb Berberi ◽  
◽  
...  

Leather is a material that has been used in different applications for centuries. Today, living in the era of high-tech¬nology, we are surrounded by smart products. For this reason, traditional products must be changed or im¬proved in order to support and make us more comfortable while using them. For instance, the touch screen display in electronics products is a smart phone’s or a tablet computer’s primary input device. Still, traditional leather will not function properly in a cold climate or other specific conditions. To make it conductive in such conditions, the double in-situ polymerization of the pyrrole coating method was used. The aim of this study was to observe the electrical properties of conductive leather. At the same time, it stands up to a wide range of different air temperatures, and relative and absolute humidity. These properties are essential because de¬signers and textile engineers should be familiar with them when they decide to use materials in different smart products. Electricity conductivity tests were carried out in year-round temperatures from 7.5 °C to 28.1 °C, with a relative humidity from 18% to 77% and a vapor air concentration from 2.77 g/kg to 12.46 g/kg. The so-called “multiple-step method” was used to test leather’s electrical resistivity for the first time. The method considers a material’s compressional properties and provides an indicator inherent for a material’s electrical properties, regardless of the mass and shape of samples. The results showed a strong dependence between water vapor air concentration and electrical resistivity, described using the formula ρ = 1.3103 H−1.04 Ωm, with a correlation coefficient of 0.87. There was no relation between relative humidity and electrical resistivity, and resistivity and air temperature. Also, the results confirmed again that changes in the shape of the sample used during tests did not influence the measurement’s results, but supported the appropriateness of the measuring method.


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