Modelling the Effects of a Vegetation Barrier on Road Dust Dispersion

2016 ◽  
Vol 821 ◽  
pp. 105-112 ◽  
Author(s):  
Viktor Šíp ◽  
Luděk Beneš
Keyword(s):  
Wind Speed ◽  
Road Traffic ◽  
Road Dust ◽  
Atmospheric Particulate Matter ◽  
Vehicular Traffic ◽  
Atmospheric Conditions ◽  
Atmospheric Stratification ◽  
Dust Dispersion ◽  
Speed Effect ◽  
Porous Obstacle

Atmospheric particulate matter (PM) is a well known risk to human health. Vehicular traffic is one of the major sources of particulates in an urban setting.We study a problem of road dust dispersion. Using CFD solver based on RANS equations, we investigate the effect of a vegetation barrier on the concentration of airborne PM induced by road traffic. Simplified 2D model of a porous obstacle adjacent to a road source of two classes of particles serves as an idealization of a real-world situation.Filtering efficiency of the barrier is investigated under varying atmospheric conditions. Our model indicate that the efficiency decreases for increasing wind speed. Effect of atmospheric stratification on~the~air quality behind the barrier is shown to be highly dependent on the wind speed.

Acoustic Modeling of Meteorological Effects on Roadway Noise

2021 ◽  
pp. 036119812199458
Author(s):  
Roger L. Wayson ◽  
Kenneth Kaliski
Keyword(s):  
Road Traffic ◽  
Traffic Noise ◽  
Model Development ◽  
The United States ◽  
Noise Model ◽  
Road Traffic Noise ◽  
Atmospheric Conditions ◽  
Noise Propagation ◽  
Transportation Research ◽  
Meteorological Effects

Modeling road traffic noise levels without including the effects of meteorology may lead to substantial errors. In the United States, the required model is the Traffic Noise Model which does not include meteorology effects caused by refraction. In response, the Transportation Research Board sponsored NCHRP 25-52, Meteorological Effects on Roadway Noise, to collect highway noise data under different meteorological conditions, document the meteorological effects on roadway noise propagation under different atmospheric conditions, develop best practices, and provide guidance on how to: (a) quantify meteorological effects on roadway noise propagation; and (b) explain those effects to the public. The completed project at 16 barrier and no-barrier measurement positions adjacent to Interstate 17 (I-17) in Phoenix, Arizona provided the database which has enabled substantial developments in modeling. This report provides more recent information on the model development that can be directly applied by the noise analyst to include meteorological effects from simple look-up tables to more precise use of statistical equations.

scholarly journals Wind plants can impact long-term local atmospheric conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nicola Bodini ◽  
Julie K. Lundquist ◽  
Patrick Moriarty
Keyword(s):  
Wind Speed ◽  
Urban Areas ◽  
Weather Prediction ◽  
Atmospheric Conditions ◽  
Near Surface ◽  
Direct Observations ◽  
Stable Conditions ◽  
Weather And Climate ◽  
Central United States

AbstractLong-term weather and climate observatories can be affected by the changing environments in their vicinity, such as the growth of urban areas or changing vegetation. Wind plants can also impact local atmospheric conditions through their wakes, characterized by reduced wind speed and increased turbulence. We explore the extent to which the wind plants near an atmospheric measurement site in the central United States have affected their long-term measurements. Both direct observations and mesoscale numerical weather prediction simulations demonstrate how the wind plants induce a wind deficit aloft, especially in stable conditions, and a wind speed acceleration near the surface, which extend $$\sim 30$$ ∼ 30  km downwind of the wind plant. Turbulence kinetic energy is significantly enhanced within the wind plant wake in stable conditions, with near-surface observations seeing an increase of more than 30% a few kilometers downwind of the plants.

Kinetic effects during ocean evaporation: observed relationship with wind speed 

2021 ◽  
Author(s):  
Daniele Zannoni ◽  
Hans Christian Steen-Larsen ◽  
Andrew Peters ◽  
Árný Erla Sveinbjörnsdóttir
Keyword(s):  
Water Vapor ◽  
Wind Speed ◽  
Water Interface ◽  
Fractionation Factor ◽  
Wind Speeds ◽  
Air Water Interface ◽  
Kinetic Fractionation ◽  
Speed Effect ◽  
Equilibrium Fractionation ◽  
Non Equilibrium

<p>Water vapor has a fundamental role in weather and climate, being the strongest natural greenhouse gas in the Earth’s atmosphere. The main source of water vapor in the atmosphere is ocean evaporation, which transfers a large amount of energy via latent heat fluxes. In the past, evaporation was intensively studied using stable isotopes because of the large fractionation effects involved during water phase changes, providing insights on processes occurring at the air-water interface. Current theories describe evaporation near the air-water interface as a combination of molecular and turbulent diffusion processes into separated sublayers. The importance of those two sublayers, in terms of total resistance to vapor transport in air, is expected to be dependent on parameters such as moisture deficit, temperature and wind speed. Non-equilibrium fractionation effects in isotopic evaporation models are then expected to be related to these physical parameters. In the last 10 years, several water vapor observations from oceanic expeditions were focused on the impact of temperature and wind speed effect, assuming the influence of those parameters on non-equilibrium fractionation in the marine boundary layer. Wind speed effect is expected to be small on total kinetic fractionation and was discussed at length but was not completely ruled out. With a gradient-diffusion approach (2 heights above the ocean surface) and Cavity Ring-Down Spectroscopy we have estimated non-equilibrium fractionation factors for <sup>18</sup>O/<sup>16</sup>O during evaporation, showing that the wind speed effect can be detected and has no significant impact on kinetic fractionation. Results obtained for wind speeds between 0 and 10 m s<sup>-1</sup> in the North Atlantic Ocean are consistent with the Merlivat and Jouzel (1979) parametrization for smooth surfaces (mean ε<sub>18</sub>=6.1‰). A small monotonic decrease of the fractionation parameter is observed as a function of 10 m wind speed (slope  ≅ 0.15 ‰ m<sup>-1</sup> s), without any evident discontinuity. However, depending on the data filtering approach it is possible to highlight a rapid decrease of the kinetic fractionation factor at low wind speed (≤ 2.5 m s<sup>-1</sup>). An evident decrease of fractionation factor is also observed for wind speeds above 10 m s<sup>-1</sup>, allowing to hypothesize the possible effect of sea spray in net evaporation flux. Considering the average wind speed over the oceans, we conclude that a constant kinetic fractionation factor for evaporation is a more simple and reasonable solution than a wind-speed dependent parametrization. </p><p> </p><p>Merlivat, L., & Jouzel, J. (1979). Global climatic interpretation of the deuterium‐oxygen 18 relationship for precipitation. Journal of Geophysical Research: Oceans, 84(C8), 5029-5033.</p>

Data Collection and Modeling Results to Permit Estimation of Meteorological Effects on Roadway Noise

2019 ◽  
Vol 2673 (11) ◽  
pp. 243-253
Author(s):  
Roger L. Wayson ◽  
Kenneth Kaliski ◽  
John M. MacDonald ◽  
Erik M. Salomons ◽  
Darlene D. Reiter
Keyword(s):  
United States ◽  
Data Collection ◽  
Road Traffic ◽  
Meteorological Data ◽  
Traffic Noise ◽  
The United States ◽  
Road Traffic Noise ◽  
Atmospheric Conditions ◽  
Noise Propagation ◽  
Meteorological Effects

The estimation of absolute road traffic noise levels without including the effects of meteorology is thought to be a major source of error in the estimation process commonly used in the United States. In response, the Transportation Research Board-sponsored NCHRP 25-52, Meteorological Effects on Roadway Noise, to collect highway noise data under different meteorological conditions, document the meteorological effects on roadway noise propagation under different atmospheric conditions, develop best practices, and provide guidance on how to (a) quantify meteorological effects on roadway noise propagation and (b) explain those effects to the public. The completed project involved collecting and analyzing 35,000 min of sound and meteorological data at 16 barrier and no-barrier measurement positions adjacent to Interstate 17 in Phoenix, Arizona. This report provides information on the data collection and the modeling recommendations. The database assembled is thought to be among the best available in the United States to permit analysis of meteorological effects on roadway noise. The study recommendations will advance the methodology for estimating the meteorological effects on roadway noise in the United States.

scholarly journals Temporal Variation of Road Dust Load and Its Size Distribution—a Comparative Study of a Porous and a Dense Pavement

2020 ◽  
Vol 231 (12) ◽  
Author(s):  
Joacim Lundberg ◽  
Mats Gustafsson ◽  
Sara Janhäll ◽  
Olle Eriksson ◽  
Göran Blomqvist ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Size Distribution ◽  
Road Traffic ◽  
Traffic Noise ◽  
Road Dust ◽  
Road Traffic Noise ◽  
Size Distributions ◽  
Abrasion Wear ◽  
Porous Pavement ◽  
Dust Load

AbstractResuspension of road dust contributes to air quality issues with resulting health impacts. Limited studies imply that porous pavements can initially mitigate PM10 emissions by acting as a dust trap, but the abrasion wear generates road dust and thus accelerates the clogging processes. In addition, knowledge regarding the impact of pavement types on road dust load dynamics is limited. Road traffic noise can be mitigated using porous pavements, but the use of studded tyres increases the abrasion wear of the pavement as well as increasing the noise emission. Due to this durability problem, porous pavements are rarely used in the Nordic countries where, instead, dense pavements which are abrasion resistant are more common. Linköping municipality, in Sweden, constructed a porous pavement to mitigate road traffic noise. This led to the opportunity to investigate the temporal variation of the dust load dynamics and inherent size distributions over the winter and spring in comparison to those of an adjacent dense pavement. Results, when using the wet dust sampler (WDS) method, showed similar dust load dynamics for the dense and porous pavements. The results were also compared to previous studies using the same method on different dense pavements in Stockholm, Sweden. All locations showed a seasonal variation with higher dust loads during winter and early spring and declining loads towards summer. The size distributions were more complex for the wheel tracks at the porous pavement, having primarily properties of a mixture model compared to the simple size distributions for the dense pavement. On the other hand, the dust load and size distribution were more similar between the porous and dense pavements regarding loads and shapes, indicating a less pronounced but similar behaviour between the surfaces outside of the wheel tracks.

The atmospheric conditions affecting sporulation of blue mould in tobacco

1964 ◽  
Vol 4 (13) ◽  
pp. 178 ◽  
Author(s):  
BG Collins
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Critical Parameter ◽  
Leaf Surface ◽  
Atmospheric Conditions ◽  
Blue Mould ◽  
Growing Seasons ◽  
Ambient Relative Humidity ◽  
Critical Relative Humidity

Conditions favouring sporulation of blue mould (Peronospora tabacina Adam) having been established in the laboratory, a theoretical model has now been used to express the critical parameter, i.e. the relative humidity near the leaf surface where the spores form, in terms of the ambient atmospheric conditions. To test the validity of this model, wind speed, air temperature, and relative humidity mere measured over four growing seasons in three tobacco crops in the Ovens Valley, Victoria, and related to times of sporulation of the mould observed concurrently in these crops. 'Critical relative humidity,' a function of wind speed, air temperature, and heat loss from the crop is shown to be a more serviceable indicator of likelihood of sporulation than either ambient relative humidity or rainfall.

scholarly journals Evaluating Temperature Measurements of the iMET-XQ, in the Field, under Varying Atmospheric Conditions

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 335 ◽  
Author(s):  
Sytske K. Kimball ◽  
Carlos J. Montalvo ◽  
Madhuri S. Mulekar
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Aluminum Coating ◽  
Temperature Measurements ◽  
Atmospheric Conditions ◽  
Radiation Shield ◽  
Wind Speeds ◽  
Outdoor Setting ◽  
Accurate Temperature ◽  
Reference Sensor

Temperature measurements of InterMET Inc. aluminum-coated iMET-XQ sensors were tested in an outdoor setting under a variety of solar radiation and wind speed conditions. Twelve unshielded sensors were mounted side-by-side on the tower of a South Alabama Mesonet weather station next to a reference sensor on the tower. The iMET-XQ temperatures were most precise and accurate in solar radiation values that were close to zero, regardless of wind speed. Under overcast conditions, wind speeds of 2 m s−1 were sufficient to obtain precise and accurate temperature measurements. During the day-time, aspiration of wind speeds higher than or equal to 3 m s−1 is sufficient. An iMET-XQ was placed in a radiation shield next to the tower reference sensor to test the need for a radiation shield. A second iMET-XQ was placed unshielded on the tower. The iMET-XQ sensors with aluminum coating do not need to be shielded, but they do need to be aspirated. It is recommended that, when taking temperature measurements using unmanned aerial vehicles (UAV) with iMET-XQ sensors, the UAV either fly at 3 m s−1, be embedded in winds of those speeds, or to use the propeller wash of the UAV to aspirate the sensors.

scholarly journals First Results of Experimental Tests of the Newly Developed NARL Phased-Array Doppler Sodar

2008 ◽  
Vol 25 (10) ◽  
pp. 1778-1784 ◽  
Author(s):  
V. K. Anandan ◽  
M. Shravan Kumar ◽  
I. Srinivasa Rao
Keyword(s):  
Wind Speed ◽  
Phased Array ◽  
Experimental Tests ◽  
Acoustic Power ◽  
Lower Atmosphere ◽  
Physical Parameters ◽  
Atmospheric Conditions ◽  
Microwave Electronics ◽  
Doppler Sodar ◽  
First Results

Abstract A multifrequency phased-array Doppler sodar system has been installed recently at the National Atmospheric Research Laboratory (NARL) for the continuous observation of the lower atmosphere from near ground to the atmospheric boundary layer (ABL). The NARL sodar, developed in technical collaboration with the Society for Applied Microwave Electronics Engineering and Research (SAMEER), was built using piezoceramic tweeters, which are capable of generating 100-W acoustic power. In favorable atmospheric conditions, the sodar gives wind profiles up to 1 km. The performance evaluation is one of the most important aspects for quality assurance of sodar operations. This paper presents the first results of experimental observations of the NARL sodar system and its scientific validation. The NARL sodar has been validated using the simultaneous observation of another sodar system (Scintec model MFAS64). Various physical parameters of the atmosphere are derived using the results obtained from both of the systems. Comparison of simultaneous measurements by both of the sodars, located about 100 m apart, shows good agreement on wind speed, wind direction, and vertical wind variance. The correlation coefficient of more than 0.80 in wind speed and direction between the sodars shows the usefulness of the system for observing the atmosphere and deriving physical parameters below the ABL.

Sign in / Sign up

Export Citation Format

Share Document