The Influence of Weather Conditions on Pedestrians’ Behavior and Motion, with Respect to Queues in Outdoor Urban Areas

Author(s):  
Ioannis Tzouvadakis ◽  
Athanassios Stamos
2008 ◽  
Vol 8 (3) ◽  
pp. 11967-11996 ◽  
Author(s):  
C. Mitsakou ◽  
G. Kallos ◽  
N. Papantoniou ◽  
C. Spyrou ◽  
S. Solomos ◽  
...  

Abstract. The desert of Sahara is one of the major sources of mineral dust on Earth, producing around 2×108 tons/yr. Under certain weather conditions, dust particles from Saharan desert get transported over the Mediterranean Sea and most of Europe. The limiting values set by the directive EC/30/1999 of European Union can easily be exceeded by the transport of desert dust particles in all south European areas and especially urban. In this study, the effects of dust transport on air quality in several Greek urban areas are quantified. PM10 concentration values from stationary monitoring stations are compared to dust concentrations for the 4-year period 2003–2006. The dust concentration values in the Greek areas were estimated by the SKIRON modelling system coupled with embedded algorithms describing the dust cycle. The mean annual dust contribution to daily-averaged PM10 concentration values was found to be around or even greater than 10% in the urban areas throughout the years examined. Natural dust transport may contribute by much more than 20% to the annual number of exceedances – PM10 values greater than EU limits – depending on the specific monitoring location. In a second stage of the study, the inhaled lung dose received by the residents in various Greek locations is calculated. The particle deposition efficiency of mineral dust at the different parts of the human respiratory tract is determined by applying a lung dosimetry numerical model, which incorporates inhalation dynamics and aerosol physical processes. The inhalation dose from mineral dust particles was greater in the upper respiratory system (extrathoracic region) and less significant in the lungs, especially in the sensitive alveolar region. However, in cases of dust episodes, the amounts of mineral dust deposited along the human lung are comparable to those received during exposure in heavily polluted urban or smoking areas.


2021 ◽  
Vol 21 (6) ◽  
pp. 4599-4614
Author(s):  
Di Liu ◽  
Wanqi Sun ◽  
Ning Zeng ◽  
Pengfei Han ◽  
Bo Yao ◽  
...  

Abstract. To prevent the spread of the COVID-19 epidemic, restrictions such as “lockdowns” were conducted globally, which led to a significant reduction in fossil fuel emissions, especially in urban areas. However, CO2 concentrations in urban areas are affected by many factors, such as weather, biological sinks and background CO2 fluctuations. Thus, it is difficult to directly observe the CO2 reductions from sparse ground observations. Here, we focus on urban ground transportation emissions, which were dramatically affected by the restrictions, to determine the reduction signals. We conducted six series of on-road CO2 observations in Beijing using mobile platforms before (BC), during (DC) and after (AC) the implementation of COVID-19 restrictions. To reduce the impacts of weather conditions and background fluctuations, we analyze vehicle trips with the most similar weather conditions possible and calculated the enhancement metric, which is the difference between the on-road CO2 concentration and the “urban background” CO2 concentration measured at the tower of the Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences. The results showed that the DC CO2 enhancement was decreased by 41 (±1.3) parts per million (ppm) and 26 (±6.2) ppm compared to those for the BC and AC trips, respectively. Detailed analysis showed that, during COVID-19 restrictions, there was no difference between weekdays and weekends during working hours (09:00–17:00 local standard time; LST). The enhancements during rush hours (07:00–09:00 and 17:00–20:00 LST) were almost twice those during working hours, indicating that emissions during rush hours were much higher. For DC and BC, the enhancement reductions during rush hours were much larger than those during working hours. Our findings showed a clear CO2 concentration decrease during COVID-19 restrictions, which is consistent with the CO2 emissions reductions due to the pandemic. The enhancement method used in this study is an effective method to reduce the impacts of weather and background fluctuations. Low-cost sensors, which are inexpensive and convenient, could play an important role in further on-road and other urban observations.


Author(s):  
J. Schachtschneider ◽  
C. Brenner

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.


Buildings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 189 ◽  
Author(s):  
Javanroodi ◽  
M.Nik

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.


Symmetry ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 821 ◽  
Author(s):  
Mohammad Ebrahimpour ◽  
Rouzbeh Shafaghat ◽  
Rezvan Alamian ◽  
Mostafa Safdari Shadloo

Exploiting wind energy, which is a complex process in urban areas, requires turbines suitable for unfavorable weather conditions, in order to trap the wind from different directions; Savonius turbines are suitable for these conditions. In this paper, the effect of overlap ratios and the position of blades on a vertical axis wind turbine is comprehensively investigated and analyzed. For this purpose, two positive and negative overlap situations are first defined along the X-axis and examined at the different tip speed ratios of the blade, while maintaining the size of the external diameter of the rotor, to find the optimum point; then, the same procedure is done along the Y-axis. The finite volume method is used to solve the computational fluid dynamics. Two-dimensional numerical simulations are performed using URANS equations and the sliding mesh method. The turbulence model employed is a realizable K-ε model. According to the values of the dynamic torque and power coefficient, while investigating horizontal and vertical overlaps along the X- and Y-axis, the blades with overlap ratios of HOLR = +0.15 and VOLR = +0.1 show better performances when compared to other corresponding overlaps. Accordingly, the average Cm and Cp improvements are 16% and 7.5%, respectively, compared to the base with a zero overlap ratio.


2011 ◽  
Vol 19 (2) ◽  
pp. 403-410 ◽  
Author(s):  
Nelson Luiz Batista de Oliveira ◽  
Regina Marcia Cardoso de Sousa

This study characterizes traffic accidents involving motorcycles according to local conditions, data concerning the type of accident, date and time, and identifies among these variables those associated with the death of victims. This retrospective study uses data from traffic collision reports from 2004 and death records from the institute of forensic medicine. A total of 99.4% of the events occurred in urban areas, where illumination (87.4%), weather conditions (80.6%); and traffic signs (70.6%) were satisfactory. Collisions between motorcycles and cars or pickup trucks prevailed (55.5%), followed by motorcycle falls (18.0%). In relation to the type of collision, the highest percentage was observed in broadside collision category (35.2%). There were differences between the groups of fatalities and survivors in relation to the area and illumination in the collision’s site, in addition to the types of collision and impact. The conclusion is that local conditions and types of collision and impact stand out among the multiple variables defining the severity of accidents involving motorcycles.


2016 ◽  
Vol 11 (2) ◽  
pp. 188-197 ◽  
Author(s):  
Takuya Oki ◽  
◽  
Toshihiro Osaragi

It is very important in disaster prevention planning to estimate the level of human damage after large earthquakes under various scenarios that takes into account the day of week, the time of the disaster, weather conditions, earthquake intensity, etc. There have been many previous studies based on the spatial characteristics of urban areas about evaluating protection against fires, evacuation risks, and the safety of evacuation routes to designated areas. However, no study so far has integrated models of property damage (building collapse, fire spread, and street blockage) and human behavior (rescue activities, firefighting activities, and wide-area evacuation behavior), and carries out simulations in order to analyze human damage in detail. In this paper, we present a survey of previous studies of the methods of evaluating urban-area characteristics, rescue and firefighting activities, and wide-area evacuation, all of which have been discussed as separate issues. We summarize the findings within the respective fields, their methods of evaluation and modeling, and identify their issues. Based on this survey, we point out that the construction of an integrated simulation model requires six important activities. They are to: 1) carry out evaluations on a microscopic scale at the block or street level; 2) use an evaluation index that allows a direct grasp of the expected level of human damage; 3) take into consideration many detailed and concrete disaster scenarios; 4) take into consideration the interactions among rescue participants, firefighting participants and wide-area evacuees, along with the effects of property damage; 5) incorporate the concept of time; and 6) set up comparative scenarios that allow the quantitative evaluation of the effects of various measures or policies. Therefore, it is necessary to construct a model based on the concept of multi-agent simulation (MAS).


2013 ◽  
Vol 28 (1) ◽  
pp. 254-269 ◽  
Author(s):  
Daniel P. Tyndall ◽  
John D. Horel

Abstract Given the heterogeneous equipment, maintenance and reporting practices, and siting of surface observing stations, subjective decisions that depend on the application tend to be made to use some observations and to avoid others. This research determines objectively high-impact surface observations of 2-m temperature, 2-m dewpoint, and 10-m wind observations using the adjoint of a two-dimensional variational surface analysis over the contiguous United States. The analyses reflect a weighted blend of 1-h numerical forecasts used as background grids and available observations. High-impact observations are defined as arising from poor observation quality, observation representativeness errors, or accurate observed weather conditions not evident in the background field. The impact of nearly 20 000 surface observations is computed over a sample of 100 analysis hours during 25 major weather events. Observation impacts are determined for each station as well as within broad network categories. For individual analysis hours, high-impact observations are located in regions of significant weather—typically, where the background field fails to define the local weather conditions. Low-impact observations tend to be ones where there are many observations reporting similar departures from the background. When averaged over the entire 100 cases, observations with the highest impact are found within all network categories and depend strongly on their location relative to other observing sites and the amount of variability in the weather; for example, temperature observations have reduced impact in urban areas such as Los Angeles, California, where observations are plentiful and temperature departures from the background grids are small.


2020 ◽  
Vol 172 ◽  
pp. 19002
Author(s):  
Kavan Javanroodi ◽  
Vahid M. Nik ◽  
Yuchen Yang

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.


2019 ◽  
Vol 8 (2S11) ◽  
pp. 1050-1052

In this work we identifying and examining the weather conditions on metropolitan area by using Big data. In this data describe the collection of data very large in size. In some urban regions transporting problem will be arrived in the changing on weather. Now this work understands the various characteristics overall city in urban areas. Some of the urban areas major pollution problem that can arrive in the motor vehicles / industries from metrological data. The data compilation process will be available in government web sites. This website used for making of see and retrieving the previous data and compare with the real data. To estimate the data mining by using Collaborative Filtering algorithm. Now going to this algorithm to estimate the real data and compare next day data.


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