Direct Measurements of New-Particle Fluxes in the Coastal Environment

2005 ◽  
Vol 2 (4) ◽  
pp. 256 ◽  
Author(s):  
Robert J. Flanagan ◽  
Michael Geever ◽  
Colin D. O'Dowd
Keyword(s):  
Aerosol Particles ◽  
Regional Scale ◽  
Coastal Environment ◽  
Photochemical Reactions ◽  
Eddy Correlation ◽  
Correlation Technique ◽  
Similar Data ◽  
Secondary Aerosol ◽  
Prevailing Wind Direction ◽  
The Impact

Environmental Context.The formation of new secondary aerosol particles in the natural atmosphere is important in terms of controlling the background aerosol population, which significantly impacts on climate. The coastal zone is perhaps the strongest natural source of new secondary aerosol particles, driven by the release of biogenic vapours, which, after undergoing photochemical reactions, lead to the massive production of nucleation mode aerosols, with concentrations often reaching in excess of 106 cm−3. Quantification of this source strength is important, particularly on a regional scale, in terms of estimating the impact of aerosols on climate. Abstract.Measurements of the flux of new secondary aerosol particles during nucleation events in the coastal environment using an eddy-correlation technique are reported for the first time. Events are divided into two types based on the prevailing wind direction. During tidal-related nucleation events, new-particle upward fluxes are typically of the order of 109–1010 particles m−2 s−1. A close correlation (r2 = 0.86) was found between total particle concentration and total (positive) flux when air masses were not affected by multiple sources. This would suggest that continuous measurements of particle number concentration at Mace Head can be translated into a flux using the resulting parameterization. It is expected that parameterizations obtained from similar data and analysis would be equally feasible at other coastal locations.

scholarly journals The comprehensive model system COSMO-ART – radiative impact of aerosol on the state of the atmosphere on the regional scale

2009 ◽  
Vol 9 (4) ◽  
pp. 14483-14528 ◽  
Author(s):  
B. Vogel ◽  
H. Vogel ◽  
D. Bäumer ◽  
M. Bangert ◽  
K. Lundgren ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Western Europe ◽  
Aerosol Particles ◽  
Regional Scale ◽  
Global Radiation ◽  
Model System ◽  
First Episode ◽  
Clear Correlation ◽  
The Impact

Abstract. A new fully online coupled model system developed for the evaluation of the interaction of aerosol particles with the atmosphere on the regional scale is described. The model system is based on the operational weather forecast model of the Deutscher Wetterdienst. Physical processes like transport, turbulent diffusion, and dry and wet deposition are treated together with photochemistry and aerosol dynamics using the modal approach. Based on detailed calculations we have developed parameterizations to examine the impact of aerosol particles on photolysis and on radiation. Currently the model allows feedback between natural and anthropogenic aerosol particles and the atmospheric variables that are initialized by the modification of the radiative fluxes. The model system is applied to two summer episodes, each lasting five days, with a model domain covering Western Europe and adjacent regions. The first episode is characterised by almost cloud free conditions and the second one by cloudy conditions. The simulated aerosol concentrations are compared to observations made at 700 stations distributed over Western Europe. For each episode two model runs are performed; one where the feedback between the aerosol particles and the atmosphere is taken into account and a second one where the feedback is neglected. Comparing these two sets of model runs, the radiative feedback on temperature and other variables is evaluated. In the cloud free case a clear correlation between the aerosol optical depth and changes in global radiation and temperature is found. In the case of cloudy conditions the pure radiative effects are superposed by changes in the liquid water content of the clouds due to changes in the thermodynamics of the atmosphere. In this case the correlation between the aerosol optical depth and its effects on temperature is low. However, on average a decrease in the 2 m temperature is still found. In both cases a reduction in the daily temperature range, due to the aerosol optical depth, can be seen with an average value of −0.13 K over Germany.

scholarly journals Roll vortices induce new particle formation bursts in the planetary boundary layer

2020 ◽  
Author(s):  
Janne Lampilahti ◽  
Hanna Elina Manninen ◽  
Katri Leino ◽  
Riikka Väänänen ◽  
Antti Manninen ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Particle Production ◽  
Aerosol Particles ◽  
Regional Scale ◽  
Particle Formation ◽  
Forest Site ◽  
New Particle Formation ◽  
Roll Vortices ◽  
The Impact

Abstract. Recent studies have shown the importance of new particle formation (NPF) to global cloud concensation nuclei (CCN) production, as well as to air pollution in megacities. In addition to the necessary presence of low-volatility vapors that can form the new aerosol particles, both numerical and observational studies have shown that the dynamics of the planetary boundary layer (BL) plays an important role in NPF. Evidence from field observations suggests that roll vortices might be favorable for inducing NPF in a convective BL. However, direct observations and estimates on the potential importance of this phenomenon to the production of new aerosol particles are lacking. Here we show that rolls frequently induce NPF bursts along the horizontal circulations, and that the small clusters and particles originating from these bursts grow in size similar to particles typically ascribed to regional-scale atmospheric NPF. We outline a method to identify roll-induced NPF from measurements and, based on the collected data, estimate the impact of roll vortices on the overall aerosol particle production due to NPF at a boreal forest site (83 ± 34 % and 26 ± 8 % overall enhancement in particle formation for 3-nm and 10-nm particles respectively). We conclude that the formation of roll vortices should be taken into account when estimating particle number budgets in the atmospheric BL.

scholarly journals The comprehensive model system COSMO-ART – Radiative impact of aerosol on the state of the atmosphere on the regional scale

2009 ◽  
Vol 9 (22) ◽  
pp. 8661-8680 ◽  
Author(s):  
B. Vogel ◽  
H. Vogel ◽  
D. Bäumer ◽  
M. Bangert ◽  
K. Lundgren ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Western Europe ◽  
Aerosol Particles ◽  
Regional Scale ◽  
Global Radiation ◽  
Model System ◽  
First Episode ◽  
Clear Correlation ◽  
The Impact

Abstract. A new fully online coupled model system developed for the evaluation of the interaction of aerosol particles with the atmosphere on the regional scale is described. The model system is based on the operational weather forecast model of the Deutscher Wetterdienst. Physical processes like transport, turbulent diffusion, and dry and wet deposition are treated together with photochemistry and aerosol dynamics using the modal approach. Based on detailed calculations we have developed parameterisations to examine the impact of aerosol particles on photolysis and on radiation. Currently the model allows feedback between natural and anthropogenic aerosol particles and the atmospheric variables that are initialized by the modification of the radiative fluxes. The model system is applied to two summer episodes, each lasting five days, with a model domain covering Western Europe and adjacent regions. The first episode is characterised by almost cloud free conditions and the second one by cloudy conditions. The simulated aerosol concentrations are compared to observations made at 700 stations distributed over Western Europe. For each episode two model runs are performed; one where the feedback between the aerosol particles and the atmosphere is taken into account and a second one where the feedback is neglected. Comparing these two sets of model runs, the radiative feedback on temperature and other variables is evaluated. In the cloud free case a clear correlation between the aerosol optical depth and changes in global radiation and temperature is found. In the case of cloudy conditions the pure radiative effects are superposed by changes in the liquid water content of the clouds due to changes in the thermodynamics of the atmosphere. In this case the correlation between the aerosol optical depth and its effects on temperature is low. However, on average a decrease in the 2 m temperature is still found. For the area of Germany we found on average for both cases a reduction in the global radiation of about 6 W m2, a decrease of the 2 m temperature of 0.1 K, and a reduction in the daily temperature range of −0.13 K.

scholarly journals Modeling the evolution of aerosol particles in a ship plume using PartMC-MOSAIC

2014 ◽  
Vol 14 (11) ◽  
pp. 5327-5347 ◽  
Author(s):  
J. Tian ◽  
N. Riemer ◽  
M. West ◽  
L. Pfaffenberger ◽  
H. Schlager ◽  
...  
Keyword(s):  
Process Analysis ◽  
Aerosol Particles ◽  
Formation Rate ◽  
Monte Carlo Model ◽  
Number Concentration ◽  
Transport Systems ◽  
Base Case ◽  
Secondary Aerosol ◽  
Order Of Magnitude ◽  
The Impact

Abstract. This study investigates the evolution of ship-emitted aerosol particles using the stochastic particle-resolved model PartMC-MOSAIC (Particle Monte Carlo model-Model for Simulating Aerosol Interactions and Chemistry). Comparisons of our results with observations from the QUANTIFY (Quantifying the Climate Impact of Global and European Transport Systems) study in 2007 in the English Channel and the Gulf of Biscay showed that the model was able to reproduce the observed evolution of total number concentration and the vanishing of the nucleation mode consisting of sulfate particles. Further process analysis revealed that during the first hour after emission, dilution reduced the total number concentration by four orders of magnitude, while coagulation reduced it by an additional order of magnitude. Neglecting coagulation resulted in an overprediction of more than one order of magnitude in the number concentration of particles smaller than 40 nm at a plume age of 100 s. Coagulation also significantly altered the mixing state of the particles, leading to a continuum of internal mixtures of sulfate and black carbon. The impact on cloud condensation nuclei (CCN) concentrations depended on the supersaturation threshold S at which CCN activity was evaluated. For the base case conditions, characterized by a low formation rate of secondary aerosol species, neglecting coagulation, but simulating condensation, led to an underestimation of CCN concentrations of about 37% for S = 0.3% at the end of the 14-h simulation. In contrast, for supersaturations higher than 0.7%, neglecting coagulation resulted in an overestimation of CCN concentration, about 75% for S = 1%. For S lower than 0.2% the differences between simulations including coagulation and neglecting coagulation were negligible. Neglecting condensation, but simulating coagulation did not impact the CCN concentrations below 0.2% and resulted in an underestimation of CCN concentrations for larger supersaturations, e.g., 18% for S = 0.6%. We also explored the role of nucleation for the CCN concentrations in the ship plume. For the base case the impact of nucleation on CCN concentrations was limited, but for a sensitivity case with higher formation rates of secondary aerosol over several hours, the CCN concentrations increased by an order of magnitude for supersaturation thresholds above 0.3%.

scholarly journals Roll vortices induce new particle formation bursts in the planetary boundary layer

2020 ◽  
Vol 20 (20) ◽  
pp. 11841-11854
Author(s):  
Janne Lampilahti ◽  
Hanna Elina Manninen ◽  
Katri Leino ◽  
Riikka Väänänen ◽  
Antti Manninen ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Particle Production ◽  
Aerosol Particles ◽  
Regional Scale ◽  
Particle Formation ◽  
Forest Site ◽  
New Particle Formation ◽  
Roll Vortices ◽  
The Impact

Abstract. Recent studies have shown the importance of new particle formation (NPF) to global cloud condensation nuclei (CCN) production, as well as to air pollution in megacities. In addition to the necessary presence of low-volatility vapors that can form new aerosol particles, both numerical and observational studies have shown that the dynamics of the planetary boundary layer (BL) plays an important role in NPF. Evidence from field observations suggests that roll vortices might be favorable for inducing NPF in a convective BL. However, direct observations and estimates of the potential importance of this phenomenon to the production of new aerosol particles are lacking. Here we show that rolls frequently induce NPF bursts along the horizontal circulations and that the small clusters and particles originating from these localized bursts grow in size similar to particles typically ascribed to atmospheric NPF that occur almost homogeneously at a regional scale. We outline a method to identify roll-induced NPF from measurements and, based on the collected data, estimate the impact of roll vortices on the overall aerosol particle production due to NPF at a boreal forest site (83 % ± 34 % and 26 % ± 8 % overall enhancement in particle formation for 3 and 10 nm particles, respectively). We conclude that the formation of roll vortices should be taken into account when estimating particle number budgets in the atmospheric BL.

Soil respiration in barley (Hordeum vulgare L.) and fallow fields

1992 ◽  
Vol 72 (4) ◽  
pp. 591-603 ◽  
Author(s):  
P. Rochette ◽  
R. L. Desjardins ◽  
E. G. Gregorich ◽  
E. Pattey ◽  
R. Lessard
Keyword(s):  
Hordeum Vulgare ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Net Photosynthesis ◽  
Eddy Correlation ◽  
Correlation Technique ◽  
Hordeum Vulgare L ◽  
Respiration Rates ◽  
Fallow Soil ◽  
The Impact

A study was carried out to quantify the diurnal variation of soil respiration in fallow and barley fields and to assess the impact of atmospheric CO2 concentration (C) and crop photosynthesis on soil respiration rates under field conditions. Soil respiration rate was measured twice a day (06:00 and 13:00 h EST) for 69 consecutive days at Ottawa, Ontario, Canada, during the 1990 growing season. Measurements were taken on fallow and under a barley (Hordeum vulgare L. ’Léger’) crop using a dynamic closed chamber system. Crop net photosynthesis was obtained by substracting soil respiration from the vertical CO2 fluxes above the crop which was obtained using the eddy correlation technique. Afternoon soil respiration averaged 22 and 17% more than that in the morning on fallow and barley soils, respectively. No correlation was found between atmospheric CO2 concentration and morning respiration rates. The two daily respiration measurements on fallow soil could be fit to the same function of soil temperature despite important differences in C at the time of measurement. These results indicate that soil temperature might account for the differences in R between morning and afternoon, and that the effect of C need not be considered for the modelling of the soil respiration diurnal cycle. Respiration in soil under barley was 25% lower than in fallow soil. Soil under barley was estimated to have at least 199 g C m−2 more than fallow soil at the time of harvest due to the lower soil respiration and to the input of carbon by barley root residues. High correlations were obtained between crop photosynthesis and soil respiration rates during vegetative and reproductive periods, confirming that the biotic plant component is an important factor controlling soil respiration rates in cropped fields. Key words: Root respiration, chamber measurements, CO2 flux, crop net photosynthesis, greenhouse gas, soil organic matter.

The Impact of Visual Stereotypes on Judgments about Rape

2016 ◽  
Vol 75 (3) ◽  
pp. 133-140
Author(s):  
Robert Busching ◽  
Johannes Lutz
Keyword(s):  
Mental Representations ◽  
Irrelevant Information ◽  
Clear Distinction ◽  
Rape Myth ◽  
Facial Features ◽  
Reverse Correlation ◽  
Correlation Technique ◽  
Specific Effects ◽  
Legal Judgments ◽  
The Impact

Abstract. Legally irrelevant information like facial features is used to form judgments about rape cases. Using a reverse-correlation technique, it is possible to visualize criminal stereotypes and test whether these representations influence judgments. In the first step, images of the stereotypical faces of a rapist, a thief, and a lifesaver were generated. These images showed a clear distinction between the lifesaver and the two criminal representations, but the criminal representations were rather similar. In the next step, the images were presented together with rape scenarios, and participants (N = 153) indicated the defendant’s level of liability. Participants with high rape myth acceptance scores attributed a lower level of liability to a defendant who resembled a stereotypical lifesaver. However, no specific effects of the image of the stereotypical rapist compared to the stereotypical thief were found. We discuss the findings with respect to the influence of visual stereotypes on legal judgments and the nature of these mental representations.

Exploring the impact of introducing a physical model into statistical methods on the evaluation of regional scale debris flow susceptibility

2021 ◽  
Vol 106 (1) ◽  
pp. 881-912
Author(s):  
Jingbo Sun ◽  
Shengwu Qin ◽  
Shuangshuang Qiao ◽  
Yang Chen ◽  
Gang Su ◽  
...  
Keyword(s):  
Debris Flow ◽  
Physical Model ◽  
Statistical Methods ◽  
Regional Scale ◽  
The Impact ◽  
Debris Flow Susceptibility

scholarly journals Access to MRI for patients with cardiac pacemakers and implantable cardioverter defibrillators

Open Heart ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. e001598
Author(s):  
Christopher Pieri ◽  
Anish Bhuva ◽  
Russell Moralee ◽  
Aderonke Abiodun ◽  
Deepa Gopalan ◽  
...  
Keyword(s):  
Supply And Demand ◽  
Complication Rates ◽  
Similar Data ◽  
Implantable Cardioverter Defibrillators ◽  
Cardiac Pacemakers ◽  
Survey Tool ◽  
Mr Conditional ◽  
Mri Scans ◽  
Implantation Rates ◽  
The Impact

ObjectiveTo determine provision of MRI for patients with cardiac implantable electronic devices (CIEDs; pacemakers and defibrillators) in England, to understand regional variation and assess the impact of guideline changes.MethodsRetrospective data related to MRI scans performed in patients with CIED over the preceding 12 months was collected using a structured survey tool distributed to every National Health Service Trust MRI unit in England. Data were compared with similar data from 2014/2015 and with demand (estimated from local CIED implantation rates and regional population data by sustainability and transformation partnerships (STPs)).ResultsResponses were received from 212 of 223 (95%) hospitals in England. 112 (53%) MRI units’ scan patients with MR-conditional CIEDs (10% also scan non-MR conditional devices), compared with 46% of sites in 2014/2015. Total annual scan volume increased over fourfold between 2014 and 2019 (1090 to 4896 scans). There was widespread geographical variation, with five STPs (total population >3·5 million representing approximately 25 000 patients with CIED) with no local provision. There was no correlation between local demand (CIED implantation rates) and MRI provision (scan volume). Complication rates were extremely low with three events nationally in 12 months (0·06% CIED–MRI scans).ConclusionsProvision of MRI for patients with CIEDs in England increased over fourfold in 4 years, but an estimated 10-fold care gap remains. Almost half of hospitals and 1 in 10 STPs have no service, with no relationship between local supply and demand. Availability of MRI for patients with non-MR conditional devices, although demonstrably safe, remains limited.

Epidemiologic Studies of Papago Indian Mortality

1972 ◽  
Vol 31 (2) ◽  
pp. 163-170 ◽  
Author(s):  
H. Tyroler ◽  
Ralph Patrick
Keyword(s):  
Causes Of Death ◽  
Reporting System ◽  
Epidemiologic Studies ◽  
Similar Data ◽  
Death Certificates ◽  
Vital Rates ◽  
Population Register ◽  
Death Rates ◽  
Department Of Health ◽  
The Impact

With data from the Papago population register and death certificates from the Arizona State Department of Health, vital rates and causes of death were examined for the decade 1950-59. Data were then divided to permit an assessment of the impact of residence in modern and traditional Papago communities on vital rates. Birth and death rates computed for the Papago population were in general agreement with similar data on Arizona Indian and U. S. Indian populations. Because of incompleteness of cause of death coding, mortality analysis was inconclusive. The vital rates for modern versus traditional communities disclosed differences which were the opposite of those predicted. Both birth and death rates were higher in modern than in traditional villages. This reversal may be explained by the inadequacy of the reporting system for vital events during the decade.

Sign in / Sign up

Export Citation Format

Share Document