scholarly journals Quantifying the impacts of urban morphology on modifying microclimate conditions in extreme weather conditions

2021 ◽  
Vol 2042 (1) ◽  
pp. 012058
Author(s):  
K. Javanroodi ◽  
V.M. Nik ◽  
JL. Scartezzini
Keyword(s):  
Wind Speed ◽  
Air Temperature ◽  
Urban Areas ◽  
Fluid Dynamic ◽  
Heat Removal ◽  
Weather Conditions ◽  
Extreme Weather ◽  
Urban Morphology ◽  
Urban Neighbourhoods ◽  
Microclimate Conditions

Abstract It is well-known that the morphology of urban areas modifies the variations of climate variables at microscale; known as microclimate conditions. The complexity of urban morphology can lead to undesired wind conditions or excessive air temperature; particularly in extreme weather conditions. This study attempts to quantify the impacts of urban morphology on the evolution of wind speed and air temperature at the urban canopy layer using Computational Fluid Dynamic (CFD) simulations. In this regard, three urban neighbourhoods are generated based on a novel urban morphology parameterization method and assessed in two extreme low and high wind conditions. Results showed that wind speed (up to 75%) and air temperature (up to 28%) at the microscale can get amplified or dampened in extreme conditions. A negative correlation was observed between wind speed and air temperature variations indicating a great potential to reduce outdoor air temperature through heat removal in urban canyons. The findings of the study are categorized based on the morphological parameters to present a series of design-based strategies for the newly-built urban neighbourhoods.

scholarly journals Impacts of Microclimate Conditions on the Energy Performance of Buildings in Urban Areas

Buildings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 189 ◽  
Author(s):  
Javanroodi ◽  
M.Nik
Keyword(s):  
Urban Areas ◽  
Energy Demand ◽  
Weather Conditions ◽  
Energy Performance ◽  
Urban Morphology ◽  
Weather Data ◽  
Architectural Form ◽  
Energy Performance Of Buildings ◽  
Microclimate Conditions ◽  
The Impact

Urbanization trends have changed the morphology of cities in the past decades. Complex urban areas with wide variations in built density, layout typology, and architectural form have resulted in more complicated microclimate conditions. Microclimate conditions affect the energy performance of buildings and bioclimatic design strategies as well as a high number of engineering applications. However, commercial energy simulation engines that utilize widely-available mesoscale weather data tend to underestimate these impacts. These weather files, which represent typical weather conditions at a location, are mostly based on long-term metrological observations and fail to consider extreme conditions in their calculation. This paper aims to evaluate the impacts of hourly microclimate data in typical and extreme climate conditions on the energy performance of an office building in two different urban areas. Results showed that the urban morphology can reduce the wind speed by 27% and amplify air temperature by more than 14%. Using microclimate data, the calculated outside surface temperature, operating temperature and total energy demand of buildings were notably different to those obtained using typical regional climate model (RCM)–climate data or available weather files (Typical Meteorological Year or TMY), i.e., by 61%, 7%, and 21%, respectively. The difference in the hourly peak demand during extreme weather conditions was around 13%. The impact of urban density and the final height of buildings on the results are discussed at the end of the paper.

scholarly journals Exposure-Dependent Variations in Air Temperature and Humidity on the Moraine of the Aavatsmark Glacier (Nw Spitsbergen) in the Summer Season of 2010

2012 ◽  
Vol 5 (1) ◽  
pp. 57-75
Author(s):  
Andrzej Araźny ◽  
Rajmund Przybylak
Keyword(s):  
Wind Speed ◽  
Air Temperature ◽  
Weather Conditions ◽  
Active Surface ◽  
Summer Season ◽  
Lateral Moraine ◽  
Near Surface ◽  
Mean Values ◽  
Temperature And Humidity ◽  
Surface Air Layer

Abstract The article presents results of research on the development of air temperature and relative humidity at a height of 5 cm above the active surface of the terminal lateral moraine of the Aavatsmark Glacier, relative to its exposure in the summer season of 2010. Variations in the two conditions were analysed for five measurement sites situated on northerly (SN), easterly (SE), southerly (SS) and westerly (SW) slopes, as well as on the flat top surface of the moraine (STop), in different weather conditions. The article also includes a temperature and humidity stratification in the near surface air layer (5-200 cm) above the moraine. The issues were investigated for mean values from the whole period of research, as well as for individual days demonstrating distinct degrees of cloudiness and wind speed.

The Influence of Weather On Incubation Scheduling of the White-Rumped Sandpiper (Calidris Fuscicollis): a Uniparental Incubator in a Cold Environment

Behaviour ◽  
1985 ◽  
Vol 95 (3-4) ◽  
pp. 261-289 ◽  
Author(s):  
Robert D. Montgomerie ◽  
Ralph V. Cantar
Keyword(s):  
Circadian Rhythm ◽  
Wind Speed ◽  
Air Temperature ◽  
Weather Conditions ◽  
Barometric Pressure ◽  
High Arctic ◽  
Collective Effects ◽  
Incubation Behaviour ◽  
The Individual

AbstractWe studied the incubation scheduling of 8 white-rumped sandpipers (Calidris fuscicollis), a species in which only the female incubates. Because the female is small and nests in the high arctic, these birds are probably under more cold stress than birds nesting in the temperate zone. We examined the individual and collective effects of several weather variables on a female's incubation behaviour to ascertain what amount of the variability within a day was directly attributable to weather conditions. Birds made an average of 25.1 off-nest trips each day, averaging 10.5 min each. This resulted in spending, on average, 82.5% of their time incubating eggs. There was a clear within-day cycle in incubation scheduling; birds made more and longer trips in the middle of the day and, as a result, spent more total time off the nest in that period. Birds adjusted their hour-by-hour schedules to weather largely by altering the number of trips made, and less so by adjusting trip length. There was a circadian rhythm in recess time/h, explaining at least 11% of the variation in recess time/h. When the circadian rhythm was controlled statistically, weather accounted for an average of 38% of the explainable variation in recess time/h. The relative importance of each weather variable on the recess time/h was (in descending order of importance): wind speed, air temperature, solar radiation, barometric pressure, and relative humidity. Weather (primarily wind speed and temperature) exerted its strongest effects early and late in the bird's active day (0400-2300 h). On cold and windy days, birds increased the time spent on their nests early and late in the day, and made more trips than usual in the middle of the day, when air temperature was highest. We suggest that the incubation scheduling of these birds conformed to the long-term predictability of the daily weather cycle by following a circadian rhythm of behaviour modified by a response to concurrent weather that would have reduced egg cooling.

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 Future scenarios of thermal bioclimatic conditions in a humid tropical city under urban development

2018 ◽  
Vol 13 (5) ◽  
pp. 1
Author(s):  
Vicente De Paulo Rodrigues da Silva ◽  
Joel Silva Santos ◽  
Eduardo Rodrigues Viana de Lima ◽  
Romildo Morant de Holanda ◽  
Enio Pereira de Sousa ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Urban Areas ◽  
Kendall Test ◽  
Future Scenarios ◽  
Rapid Urbanization ◽  
Mann Kendall Test ◽  
Bioclimatic Conditions ◽  
The City

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.

Urban-rural contrasts and extreme weather conditions in regional climate change projections across spatial and temporal scales

2020 ◽  
Author(s):  
Gaby S. Langendijk ◽  
Diana Rechid ◽  
Daniela Jacob
Keyword(s):  
Climate Change ◽  
Urban Areas ◽  
Climate Models ◽  
Regional Climate ◽  
Climate Change Impacts ◽  
Regional Climate Models ◽  
Weather Conditions ◽  
Extreme Weather ◽  
Climate Projections ◽  
Urban Rural

&lt;p&gt;Urban areas are prone to climate change impacts. A transition towards sustainable urban areas is relying heavily on useful, evidence-based climate information on urban scales. However, current climate data and information produced by urban or climate models are are either not scale compliant for cities, or do not cover essential parameters and/or urban-rural interactions under climate change conditions. Furthermore, although e.g. the urban heat island may be better understood, other phenomena, such as moisture change, are little researched. Our research shows the potential of regional climate models, within the EURO-CORDEX framework, to provide climate projections and information on urban scales for 11km and 3km grid size. The city of Berlin is taken as a case-study. The results on the 11km spatial scale show that the regional climate models simulate a distinct difference between Berlin and its surroundings for temperature and humidity related variables. There is an increase in urban dry island conditions in Berlin towards the end of the 21st century. To gain a more detailed understanding of climate change impacts, extreme weather conditions were investigated under a 2&amp;#176;C global warming and further downscaled to the 3km scale. This enables the exploration of differences of the meteorological processes between the 11km and 3km scales, and the implications for urban areas and its surroundings. The overall study shows the potential of regional climate models to provide climate change information on urban scales.&amp;#160;&lt;/p&gt;

Estimation of Wind Speeds in Urban Areas Using Look-up Tables for Wind-speed Change Rate Simulated by a CFD Model

2020 ◽  
Author(s):  
Jang-Woon Wang ◽  
Jae-Jin Kim ◽  
Ho-Jin Yang
Keyword(s):  
Wind Speed ◽  
Urban Areas ◽  
Urban Morphology ◽  
Average Height ◽  
Target Area ◽  
Cfd Model ◽  
Parameterization Method ◽  
Wind Speeds ◽  
Speed Change ◽  
Morphology Parameters

&lt;p&gt;In this study, we developed a new urban parameterization method of wind speeds. The parameterization method uses building morphology parameters (the volumetric fraction, the plane area fraction, and the average height of buildings) for three different areas. For this, we investigated the relationships between the wind speed change rates by buildings and the urban parameters in three target areas. Each target area includes an automated weather station (AWS) at its center. We conducted the multiple regression analysis to make look-up tables for the relationships between the wind speed change rates and the urban morphology parameters for 32 inflow directions in the target areas. For validation, we simulated the wind speeds at the AWSs using a CFD model coupled to the local data assimilation and prediction system (LDAPS), one of the operational numerical prediction systems of the Korean Meteorological Administration. The results showed that the estimated wind speeds at the AWSs in the three target areas were very similar to those simulated by the LDAPS-CFD coupled model as well as those observed at the AWSs.&lt;/p&gt;

Cloudiness and weather variation in central Svalbard in July 2013 as related to atmospheric circulation

2013 ◽  
Vol 3 (2) ◽  
pp. 184-195 ◽  
Author(s):  
Kamil Láska ◽  
Zuzana Chládová ◽  
Klára Ambrožová ◽  
Jan Husák
Keyword(s):  
Wind Speed ◽  
Atmospheric Circulation ◽  
Air Temperature ◽  
Rapid Change ◽  
Weather Conditions ◽  
Heavy Precipitation ◽  
Circulation Pattern ◽  
Free Zone ◽  
Circulation Types ◽  
Weather Variation

The paper describes synoptic situations and associated weather conditions in the central part of the Svalbard Arctic archipelago (Petuniabukta, Billefjorden) during two weeks of the summer 2013. The circulation types in July 2013 were compared with the long-term average circulation pattern in the period 1961–2010. Cloudiness and weather conditions in different atmospheric circulation types were described. Atmospheric pressure, 2-m air temperature, precipitation, 6-m wind speed and wind direction data from an automatic weather station located on the coastal glacier-free zone of Petuniabukta were used for further analysis. From July 5 to 19, 2013, radiation and advection weather types, heavy precipitation, rapid change of wind speed, 2-m air temperature and high cloudiness variation were described in detail within of the five most frequent synoptic situations. Foehn and halo phenomena were also reported in the study period.

Estimating absolute densities of the bushfly, Musca vetustissima Walker (Diptera: Muscidae), using West Australian blowfly traps

1981 ◽  
Vol 71 (2) ◽  
pp. 329-337 ◽  
Author(s):  
W. G. Vogt ◽  
T. L. Woodburn ◽  
G. W. Crompton
Keyword(s):  
Wind Speed ◽  
Population Density ◽  
Air Temperature ◽  
Recovery Rate ◽  
Weather Conditions ◽  
Mean Wind Speed ◽  
Dispersal Distances ◽  
True Population

AbstractCatches of Musca vetustissima Wlk. in West Australian blowfly traps containing week-old baits were consistently greater (4·5–24·1 times higher) than in traps with fresh baits. Recovery of marked flies within 26·5h of release showed mean dispersal distances of 1·5 ± 0·7 km for males and 1·6 ± 0·6 km for females under favourable weather conditions (mean air temperature 28·8°C and mean wind speed 5·5 m/s). The recovery rate of males (1·3%) and females (1·0%) over this period indicates the feasibility of using single mark-release experiments to estimate absolute fly densities. It is shown that estimates having a 95% probability of being within ± 10% of the true population density could be achieved by the release of 39 000 marked flies.

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