A wide-range electrometer voltmeter for atmospheric measurements in thunderstorms and disturbed meteorological conditions

2002 ◽  
Vol 73 (2) ◽  
pp. 482-483 ◽  
Author(s):  
R. G. Harrison
Keyword(s):  
Meteorological Conditions ◽  
Atmospheric Measurements ◽  
Wide Range

scholarly journals Comparison of OH reactivity measurements in the atmospheric simulation chamber SAPHIR

2017 ◽  
Author(s):  
Hendrik Fuchs ◽  
Anna Novelli ◽  
Michael Rolletter ◽  
Andreas Hofzumahaus ◽  
Eva Y. Pfannerstill ◽  
...  
Keyword(s):  
Water Vapor ◽  
Organic Compounds ◽  
Limit Of Detection ◽  
Measurement Techniques ◽  
Oh Radical ◽  
Atmospheric Measurements ◽  
Radical Reactivity ◽  
Wide Range ◽  
Chemical Conditions ◽  
Simulation Chamber

Abstract. Hydroxyl (OH) radical reactivity (kOH) has been measured for 18 years with different measurement techniques. In order to compare the performances of instruments deployed in the field, two campaigns were conducted performing experiments in the atmospheric simulation chamber SAPHIR at Forschungszentrum Jülich in October 2015 and April 2016. Chemical conditions were chosen either to be representative of the atmosphere or to test potential limitations of instruments. All types of instruments that are currently used for atmospheric measurements took part in one of the two campaigns. The results of these campaigns demonstrate that OH reactivity can be accurately measured for a wide range of atmospherically relevant chemical conditions (e.g. water vapor, nitrogen oxides, various organic compounds) by all instruments. The precision of the measurements (limit of detection

NESTED HIGH-RESOLUTION NOx AND PM SIMULATIONS OVER ZÜRICH

2021 ◽  
Author(s):  
Ivo Suter ◽  
Lukas Emmenegger ◽  
Dominik Brunner
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Boundary Conditions ◽  
Meteorological Conditions ◽  
Model Systems ◽  
Multi Scale ◽  
Wide Range ◽  
The Impact ◽  
The City ◽  
Concentration Levels

<p>Reducing air pollution, which is the world's largest single environmental health risk, demands better-informed air quality policies. Consequently, multi-scale air quality models are being developed with the goal to resolve cities. One of the major challenges in such model systems is to accurately represent all large- and regional-scale processes that may critically determine the background concentration levels over a given city. This is particularly true for longer-lived species such as aerosols, for which background levels often dominate the concentration levels, even within the city. Furthermore, the heterogeneous local emissions, and complex dispersion in the city have to be considered carefully.</p><p>In this study, the impact of processes across a wide range of scales on background concentrations over Switzerland and the city of Zurich was modelled by performing one year of nested European and Swiss national COSMO-ART simulations to obtain adequate boundary conditions for gas-phase chemical, aerosol and meteorological conditions for city-resolving simulations. The regional climate chemistry model COSMO-ART (Vogel et al. 2009) was used in a 1-way coupled mode. The outer, European, domain, which was driven by chemical boundary conditions from the global MOZART model, had a 6.6 km horizontal resolution and the inner, Swiss, domain one of 2.2 km. For the city scale, a catalogue of more than 1000 mesoscale flow patterns with 100 m resolution was created with the model GRAMM, based on a discrete set of atmospheric stabilities, wind speeds and directions, accounting for the influence of land-use and topography. Finally, the flow around buildings was solved with the CFD model GRAL forced at the boundaries by GRAMM. Subsequently, Lagrangian dispersion simulations for a set of air pollutants and emission sectors (traffic, industry, ...) based on extremely detailed building and emission data was performed in GRAL. The result of this nested procedure is a library of 3-dimensional air pollution maps representative of hourly situations in Zurich (Berchet et al. 2017). From these pre-computed situations, time-series and concentration maps can be obtained by selecting situations according to observed or modelled meteorological conditions.</p><p>The results were compared to measurements from air quality monitoring network stations. Modelled concentrations of NO<sub>x</sub> and PM compared well to measurements across multiple locations, provided background conditions were considered carefully. The nested multi-scale modelling system COSMO-ART/GRAMM/GRAL can adequately reproduce local air quality and help understanding the relative contributions of local versus distant emissions, as well as fill the space between precise point measurements from monitoring sites. This information is useful for research, policy-making, and epidemiological studies particularly under the assumption that exceedingly high concentrations become more and more localised phenomenon in the future.</p>

scholarly journals Effects of gas–wall interactions on measurements of semivolatile compounds and small polar molecules

2019 ◽  
Vol 12 (6) ◽  
pp. 3137-3149 ◽  
Author(s):  
Xiaoxi Liu ◽  
Benjamin Deming ◽  
Demetrios Pagonis ◽  
Douglas A. Day ◽  
Brett B. Palm ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Transmission Efficiency ◽  
Polar Molecules ◽  
Ionization Mass ◽  
Atmospheric Measurements ◽  
Wide Range ◽  
Teflon Tubing ◽  
Gas Interactions

Abstract. Recent work has quantified the delay times in measurements of volatile organic compounds (VOCs) caused by the partitioning between the gas phase and the surfaces of the inlet tubing and instrument itself. In this study we quantify wall partitioning effects on time responses and transmission of multifunctional, semivolatile, and intermediate-volatility organic compounds (S/IVOCs) with saturation concentrations (C∗) between 100 and 104 µg m−3. The instrument delays of several chemical ionization mass spectrometer (CIMS) instruments increase with decreasing C∗, ranging from seconds to tens of minutes, except for the NO3- CIMS where it is always on the order of seconds. Six different tubing materials were tested. Teflon, including PFA, FEP, and conductive PFA, performs better than metals and Nafion in terms of both delay time and transmission efficiency. Analogous to instrument responses, tubing delays increase as C∗ decreases, from less than a minute to >100 min. The delays caused by Teflon tubing vs. C∗ can be modeled using the simple chromatography model of Pagonis et al. (2017). The model can be used to estimate the equivalent absorbing mass concentration (Cw) of each material, and to estimate delays under different flow rates and tubing dimensions. We also include time delay measurements from a series of small polar organic and inorganic analytes in PFA tubing measured by CIMS. Small polar molecules behave differently than larger organic ones, with their delays being predicted by their Henry's law constants instead of their C∗, suggesting the dominance of partitioning to small amounts of water on sampling surfaces as a result of their polarity and acidity properties. PFA tubing has the best performance for gas-only sampling, while conductive PFA appears very promising for sampling S/IVOCs and particles simultaneously. The observed delays and low transmission both affect the quality of gas quantification, especially when no direct calibration is available. Improvements in sampling and instrument response are needed for fast atmospheric measurements of a wide range of S/IVOCs (e.g., by aircraft or for eddy covariance). These methods and results are also useful for more general characterization of surface–gas interactions.

scholarly journals Effects of Gas-Wall Interactions on Measurements of Semivolatile Compounds and Small Polar Molecules

2019 ◽  
Author(s):  
Xiaoxi Liu ◽  
Benjamin Deming ◽  
Demetrios Pagonis ◽  
Douglas A. Day ◽  
Brett B. Palm ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Transmission Efficiency ◽  
Polar Molecules ◽  
Ionization Mass ◽  
Atmospheric Measurements ◽  
Wide Range ◽  
Teflon Tubing ◽  
Gas Interactions

Abstract. Recent work has quantified the delay times in measurements of volatile organic compounds (VOCs) caused by the partitioning between the gas phase and the surfaces of the inlet tubing and instrument itself. In this study we quantify wall partitioning effects on time responses and transmission of multi-functional, semivolatile and intermediate-volatility organic compounds (S/IVOCs) with saturation concentrations (C*) between 100 and 104 µg m−3. The instrument delays of several chemical ionization mass spectrometer (CIMS) instruments increase with decreasing C*, ranging from seconds to tens of minutes, except for the NO3−-CIMS where it is always on the order of seconds. Six different tubing materials were tested. Teflon, including PFA, FEP, and conductive PFA, performs better than metals and Nafion in terms of both delay time and transmission efficiency. Analogous to instrument responses, tubing delays increase as C* decreases, from less than a minute to > 100 min. The delays caused by Teflon tubing vs. C* can be modeled using the simple chromatography model of Pagonis et al. (2017). The model can be used to estimate the equivalent absorbing mass concentration (Cw) of each material, and to estimate delays under different flow rates and tubing dimensions. We also include time delay measurements from a series of small polar organic and inorganic analytes in PFA tubing measured by CIMS. Small polar molecules behave differently than larger organic ones, with their delays being predicted by their Henry’s law constants instead of their C*, suggesting the dominance of partitioning to small amounts of water on sampling surfaces as a result of their polarity and acidity properties. PFA tubing has the best performance for gas-only sampling, while conductive PFA appears very promising for sampling S/IVOCs and particles simultaneously. The observed delays and low transmission both affect the quality of gas quantification, especially when no direct calibration is available. Improvements in sampling and instrument response are needed for fast atmospheric measurements of a wide range of S/IVOCs (e.g., by aircraft or for eddy covariance). These methods and results are also useful for more general characterization of surface/gas interactions.

scholarly journals The Power Curve Working Group's Assessment of Wind Turbine Power Performance Prediction Methods

2019 ◽  
Author(s):  
Joseph C. Y. Lee ◽  
Peter Stuart ◽  
Andrew Clifton ◽  
M. Jason Fields ◽  
Jordan Perr-Sauer ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Statistical Tests ◽  
Power Production ◽  
Meteorological Conditions ◽  
Power Curve ◽  
Power Performance ◽  
Power Prediction ◽  
Baseline Method ◽  
Data Set ◽  
Wide Range

Abstract. Wind turbine power production deviates from the reference power curve in real-world atmospheric conditions. Correctly predicting turbine power performance requires models to be validated for a wide range of wind turbines using inflow in different locations. The Share-3 exercise is the most recent intelligence-sharing exercise of the Power Curve Working Group, which aims to advance the modeling of turbine performance. The goal of the exercise is to search for modeling methods that reduce error and uncertainty in power prediction when wind shear and turbulence digress from design conditions. Herein, we analyze the data of 55 wind turbine power performance tests from 9 contributing organizations with statistical tests to quantify the skills of the prediction-correction methods. We assess the accuracy and precision of four proposed trial methods against the Baseline method, which uses the conventional definition of power curve with wind speed and air density at hub height. The trial methods reduce power-production prediction errors compared to the Baseline method at high wind speeds, which contribute heavily to power production; however, the trial methods fail to significantly reduce prediction uncertainty in most meteorological conditions. For the meteorological conditions when a wind turbine produces less than the power its reference power curve suggests, using power deviation matrices leads to more accurate power prediction. We also identify that for more than half of the submissions, the data set has a large influence on the effectiveness of a trial method. Overall, this work affirms the value of data-sharing efforts in advancing power-curve modeling and establishes the groundwork for future collaborations.

scholarly journals Mobile atmospheric measurements and local-scale inverse estimation of the location and rates of brief CH<sub>4</sub> and CO<sub>2</sub> releases from point sources

2021 ◽  
Vol 14 (9) ◽  
pp. 5987-6003
Author(s):  
Pramod Kumar ◽  
Grégoire Broquet ◽  
Camille Yver-Kwok ◽  
Olivier Laurent ◽  
Susan Gichuki ◽  
...  
Keyword(s):  
Mole Fraction ◽  
Cross Sections ◽  
Dispersion Model ◽  
Local Scale ◽  
Point Sources ◽  
Mitigation Strategies ◽  
Dispersion Modeling ◽  
Plume Dispersion ◽  
Atmospheric Measurements ◽  
Wide Range

Abstract. We present a local-scale atmospheric inversion framework to estimate the location and rate of methane (CH4) and carbon dioxide (CO2) releases from point sources. It relies on mobile near-ground atmospheric CH4 and CO2 mole fraction measurements across the corresponding atmospheric plumes downwind of these sources, on high-frequency meteorological measurements, and on a Gaussian plume dispersion model. The framework exploits the scatter of the positions of the individual plume cross sections, the integrals of the gas mole fractions above the background within these plume cross sections, and the variations of these integrals from one cross section to the other to infer the position and rate of the releases. It has been developed and applied to provide estimates of brief controlled CH4 and CO2 point source releases during a 1-week campaign in October 2018 at the TOTAL experimental platform TADI in Lacq, France. These releases typically lasted 4 to 8 min and covered a wide range of rates (0.3 to 200 g CH4/s and 0.2 to 150 g CO2/s) to test the capability of atmospheric monitoring systems to react fast to emergency situations in industrial facilities. It also allowed testing of their capability to provide precise emission estimates for the application of climate change mitigation strategies. However, the low and highly varying wind conditions during the releases added difficulties to the challenge of characterizing the atmospheric transport over the very short duration of the releases. We present our series of CH4 and CO2 mole fraction measurements using instruments on board a car that drove along roads ∼50 to 150 m downwind of the 40 m × 60 m area for controlled releases along with the estimates of the release locations and rates. The comparisons of these results to the actual position and rate of the controlled releases indicate ∼10 %–40 % average errors (depending on the inversion configuration or on the series of tests) in the estimates of the release rates and ∼30–40 m errors in the estimates of the release locations. These results are shown to be promising, especially since better results could be expected for longer releases and under meteorological conditions more favorable to local-scale dispersion modeling. However, the analysis also highlights the need for methodological improvements to increase the skill for estimating the source locations.

scholarly journals Mobile atmospheric measurements and local-scale inverse estimation of the location and rates of brief CH<sub>4</sub> and CO<sub>2</sub> releases from point sources

2020 ◽  
Author(s):  
Pramod Kumar ◽  
Grégoire Broquet ◽  
Camille Yver-Kwok ◽  
Olivier Laurent ◽  
Susan Gichuki ◽  
...  
Keyword(s):  
Cross Sections ◽  
Dispersion Model ◽  
Local Scale ◽  
Point Sources ◽  
Mitigation Strategies ◽  
Average Error ◽  
Dispersion Modeling ◽  
Plume Dispersion ◽  
Atmospheric Measurements ◽  
Wide Range

Abstract. We present a local-scale atmospheric inversion framework to estimate the location and rate of methane (CH4) and carbon dioxide (CO2) releases from point sources. It relies on mobile near-ground atmospheric CH4 and CO2 mole fraction measurements across the corresponding atmospheric plumes downwind the sources, on high-frequency meteorological measurements, and a Gaussian plume dispersion model. It exploits the spread of the positions of individual plume cross-sections and the integrals of the gas mole fractions above the background within these plume cross-sections to infer the position and rate of the releases. It has been developed and applied to provide estimates of brief controlled CH4 and CO2 point source releases during a one-week campaign in October 2018 at the TOTAL's experimental platform TADI in Lacq, France. These releases lasted typically 4 to 8 minutes and covered a wide range of rates (0.3 to 200 gCH4/s and 0.2 to 150 gCO2/s) to test the capability of atmospheric monitoring systems to react fast to emergency situations in industrial facilities. It also allowed testing their capability to provide precise emission estimates for the application of climate change mitigation strategies. However, the low and highly varying wind conditions during the releases added difficulties to the challenge of characterizing the atmospheric transport over the very short duration of the releases. We present our series of measurements of CH4 and CO2 mole fractions using instruments onboard a car that drives along the roads ~50 to 150 m downwind the 40 m × 60 m area of controlled releases for each of the releases and the results from the inversions of the release locations and rates. The comparisons of these results to the actual position and rate of the controlled release indicate a 20 %–30 % average error on the release rates and a ~30–40 m errors in the estimates of the release locations. These results are shown to be promising especially since better results could be expected for longer releases and under meteorological conditions more favorable to local scale dispersion modeling.

scholarly journals Urban source term estimation for mercury using a boundary-layer budget method

2018 ◽  
Author(s):  
Basil Denzler ◽  
Christian Bogdal ◽  
Cyrill Kern ◽  
Anna Tobler ◽  
Jing Huo ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Mercury ◽  
Point Sources ◽  
Atmospheric Pollutants ◽  
Atmospheric Measurements ◽  
Mercury Emission ◽  
Bottom Up ◽  
Mercury Emissions ◽  
Wide Range ◽  
The City

Abstract. Mercury is a heavy metal of particular concern due to its adverse effects on the human health and the environment. Recognizing this problem, the UN Minamata Convention on Mercury was recently adopted, where signatory countries agreed to reduce anthropogenic mercury emissions. To evaluate the effectiveness of the convention, quantitative knowledge on mercury emissions is crucial. So far, bottom-up approaches have successfully been applied to quantify mercury emission – especially for point sources. Distributed sources make up for a large share of the emission, however, they are still poorly characterized. Here, we present a top-down approach to estimate mercury emissions based on atmospheric measurements in the city of Zurich, Switzerland. While monitoring the atmospheric mercury concentrations during inversion periods in Zurich, we were able to relate the concentration increase to the mercury emission strength of the city using a box model. By the means of this boundary-layer budget approach, we succeeded to narrow down the emissions of Zurich to range between 41 ± 8 kg/a (upper bound) and 24 ± 8 kg/a (lower bound). Thereby, we could quantify emissions from mixed, diffuse and point like sources and derive an annual mercury per capita emission of 0.06 to 0.10 g/a. The approach presented here has the potential to support authorities in setting up inventories and to validate emission estimations derived from the commonly applied bottom-up approaches. Furthermore, our method is applicable to other compounds and to a wide range of cities or other areas, where sources or as well sinks for mercury and other atmospheric pollutants are presumed.

scholarly journals Theoretical implication of reversals of the ozone weekend effect systematically observed in Japan

2010 ◽  
Vol 10 (14) ◽  
pp. 6765-6776 ◽  
Author(s):  
A. Kannari ◽  
T. Ohara
Keyword(s):  
Solar Energy ◽  
Rural Areas ◽  
Geographical Area ◽  
Source Area ◽  
Theoretical Implication ◽  
Meteorological Conditions ◽  
Weekend Effect ◽  
Daily Maximum ◽  
Ozone Formation ◽  
Wide Range

Abstract. Systematic changes of the ozone weekend effect are found over broad areas of Japan. These changes are characterized by (1) spatial reversals from a weekend increase in the vicinity of huge precursor source areas to a weekend decrease in the surrounding rural areas, and (2) temporal reversals from a weekend increase under relatively unsuitable meteorological conditions for ozone formation to a weekend decrease under relatively suitable conditions. We developed a simple numerical advection–reaction model to explain the relationship between the duration of advection and the supplied solar energy, which causes the daily maximum ozone concentration to be lower near the precursor source. Ozone isopleth diagrams for individual advection durations (equivalent to the distance from the source) for a wide range of initial precursor conditions show that both VOC-limited and NOx-limited regimes exist for each advection duration, but the area of NOx-limited regime becomes dominant as the advection duration increases because of the increased exposure of the air mass to solar energy. For given initial VOC and NOx concentrations, the area remote from the source becomes a NOx-limited regime even if the precursor source area is in the VOC-limited regime. The rate of reduction of weekend emissions of NOx is larger than that of VOC, causing a weekend increase in ozone inside an area of VOC-limited regime near the source, but a weekend decrease in remote areas with a NOx-limited regime. The boundary between these two ozone formation regimes depends on meteorological conditions: when sunlight intensity and temperature are relatively low, the change from a VOC-limited to a NOx-limited regime occurs at a point more remote from the source than when they are relatively high, which causes a prevailing ozone weekend increase over a wide geographical area on days with lower ozone potential. Therefore, observations of ozone weekend changes can be interpreted in light of the theoretical implications of our model; they can be used for determination of ozone formation regimes, which change in different locations and under different meteorological conditions.

Statistical modelling of combined ozone-temperature events in Europe

2020 ◽  
Author(s):  
Sally Jahn ◽  
Elke Hertig
Keyword(s):  
Human Health ◽  
Air Temperature ◽  
Statistical Modelling ◽  
Meteorological Conditions ◽  
Photochemical Reactions ◽  
Air Pollutant ◽  
Urban Traffic ◽  
Ozone Formation ◽  
Regional Patterns ◽  
Wide Range

&lt;p&gt;Air pollution as well as high air temperature both pose a large risk to human health in Europe. High temperature levels are associated with an exceptionally high mortality rate, only representing the extreme end of a wide range of possible health effects. Tropospheric ozone, a secondary air pollutant, is primarily built by photochemical reactions under solar radiation with the involvement of precursor gases including nitrogen oxides, carbon monoxide, methane, and non-methane volatile organic compounds. Due to the specific characteristics of ozone formation, high levels of ozone and temperature often coincide, posing an even intensified threat to human health.&lt;/p&gt;&lt;p&gt;The current scientific work focuses on the co-occurrence of these two health stressors as well as their underlying meteorological conditions. A subset of European ozone (AirBase_v8, EEA) and temperature (ECA&amp;D) stations is selected for analysis based on individual station locations and data coverage. Taking into account different settings of air substances concentrations (urban, outer conurbation area, rural regions), these stations are classified and grouped by station type and area type resulting in five distinct station classes: urban traffic, urban background, suburban background, rural background and rural industrial.&lt;/p&gt;&lt;p&gt;Maximum daily 8-hour average ozone values (MDA8O3, EEA), observed daily maximum air temperatures (TX, ECA&amp;D) and meteorological variables (from ERA5, ECMWF) form the data basis for model building. Current thresholds and extreme definitions e.g. based on WHO air quality guidelines or high percentiles (75&lt;sup&gt;th&lt;/sup&gt; and 90&lt;sup&gt;th&lt;/sup&gt;) are examined and discussed to describe elevated levels of these variables and to finally define combined ozone-temperature events.&lt;/p&gt;&lt;p&gt;Possible regional patterns as well as disparities between urban and rural areas regarding the specific settings for ozone formation as well as varying meteorological mechanisms for the occurrence of combined ozone-temperature events are closely examined. The methodological focus is primary on statistical modelling, the application and comparison of varying multivariate statistical approaches and different machine learning methods, e.g. various regression analyses using shrinkage methods or random forests. Consequently, statistical models are generated to analyse the influence of meteorological conditions on the occurrence of combined ground-level ozone and temperature events along with the identification of primary key factors (e.g. ozone persistence or larger-scale air temperature and wind conditions) at each specific location.&lt;/p&gt;&lt;p&gt;Furthermore, frequency and intensity changes of combined ozone-temperate events in the scope of global warming are assessed. Thus, projections of these co-occurring events under the constraints of ongoing climate change until the end of the 21st century are analysed by integrating projections of general circulation models into the statistical modelling process.&lt;/p&gt;

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