scholarly journals Spatial extent of new particle formation events over the Mediterranean Basin from multiple ground-based and airborne measurements

2017 ◽  
Vol 17 (15) ◽  
pp. 9567-9583 ◽  
Author(s):  
Kevin Berland ◽  
Clémence Rose ◽  
Jorge Pey ◽  
Anais Culot ◽  
Evelyn Freney ◽  
...  
Keyword(s):  
Size Distribution ◽  
Regional Scale ◽  
Particle Formation ◽  
Spatial Extent ◽  
Aerosol Size Distribution ◽  
Spatial And Temporal Variability ◽  
New Particle Formation ◽  
Airborne Measurements ◽  
Synoptic Conditions ◽  
The Mediterranean

Abstract. Over the last two decades, new particle formation (NPF), i.e., the formation of new particle clusters from gas-phase compounds followed by their growth to the 10–50 nm size range, has been extensively observed in the atmosphere at a given location, but their spatial extent has rarely been assessed. In this work, we use aerosol size distribution measurements performed simultaneously at Ersa (Corsica) and Finokalia (Crete) over a 1-year period to analyze the occurrence of NPF events in the Mediterranean area. The geographical location of these two sites, as well as the extended sampling period, allows us to assess the spatial and temporal variability in atmospheric nucleation at a regional scale. Finokalia and Ersa show similar seasonalities in the monthly average nucleation frequencies, growth rates, and nucleation rates, although the two stations are located more than 1000 km away from each other. Within this extended period, aerosol size distribution measurements were performed during an intensive campaign (3 July to 12 August 2013) from a ground-based station on the island of Mallorca, as well as onboard the ATR-42 research aircraft. This unique combination of stationary and mobile measurements provides us with detailed insights into the horizontal and vertical development of the NPF process on a daily scale. During the intensive campaign, nucleation events occurred simultaneously both at Ersa and Mallorca over delimited time slots of several days, but different features were observed at Finokalia. The results show that the spatial extent of the NPF events over the Mediterranean Sea might be as large as several hundreds of kilometers, mainly determined by synoptic conditions. Airborne measurements gave additional information regarding the origin of the clusters detected above the sea. The selected cases depicted contrasting situations, with clusters formed in the marine boundary layer or initially nucleated above the continent or in the free troposphere (FT) and further transported above the sea.

scholarly journals Spatial Extent of New Particle Events over the Mediterranean basin from multiple ground-based and airborne measurements

2016 ◽  
Author(s):  
Kevin Berland ◽  
Clémence Rose ◽  
Jorge Pey ◽  
Anais Culot ◽  
Evelyn Freney ◽  
...  
Keyword(s):  
Size Distribution ◽  
Marine Boundary Layer ◽  
Regional Scale ◽  
Geographical Location ◽  
Spatial Extent ◽  
Aerosol Size Distribution ◽  
Spatial And Temporal Variability ◽  
Airborne Measurements ◽  
Synoptic Conditions ◽  
The Mediterranean

Abstract. Over the last two decades, new particle formation (NPF), i.e. the formation of new particle clusters from gas-phase compounds followed by their growth to the 10–50 nm size range, has been extensively observed in the atmosphere at a given location, but their spatial extent rarely assessed. In this work, we use aerosol size distribution measurements performed simultaneously at Ersa (Corsica) and Finokalia (Crete) over a one-year period for analyzing the occurrence of NPF events in the Mediterranean area. The geographical location of these two sites, as well as the extended sampling period allow us to assess the spatial and temporal variability of atmospheric nucleation at a regional scale. Globally, Finokalia and Ersa show similar seasonalities in the monthly average nucleation frequencies, growth rates, and nucleation rates although the two stations are located more than 1000 km away from each other. Within this extended period, aerosol size distribution measurements were performed during an intensive campaign (July 3rd to August 12th 2013) from a ground based station on the island of Mallorca, as well as onboard the ATR-42 research aircraft. This unique combination of stationary and mobile measurements provides us with detailed insights into the horizontal and vertical development of the NPF process on the daily scale. During the intensive campaign, nucleation events occurred simultaneously both at Ersa and Mallorca over delimited time slots of several days, but different features were observed at Finokalia. The results highlight that the spatial extent of the NPF events over the Mediterranean Sea might be as large as several hundreds of kilometers, mainly determined by synoptic conditions. Airborne measurements gave additional information regarding the origin of the clusters detected above the sea. The selected cases depicted contrasting situations, with clusters formed in the marine boundary layer or initially nucleated above the continent or in the Free Troposphere (FT) and further transported above the sea.

scholarly journals New-particle formation, growth and climate-relevant particle production in Egbert, Canada: analysis from one year of size-distribution observations

2014 ◽  
Vol 14 (1) ◽  
pp. 707-750 ◽  
Author(s):  
J. R. Pierce ◽  
D. M. Westervelt ◽  
S. A. Atwood ◽  
E. A. Barnes ◽  
W. R. Leaitch
Keyword(s):  
Size Distribution ◽  
Growth Rates ◽  
Particle Production ◽  
Air Flow ◽  
Regional Scale ◽  
Particle Formation ◽  
Particle Nucleation ◽  
New Particle Formation ◽  
Synoptic Conditions ◽  
One Year

Abstract. Aerosol particle nucleation, or new-particle formation, is the dominant contributor to particle number in the atmosphere. However, these particles must grow through condensation of low-volatility vapors without coagulating with the larger, pre-existing particles in order to reach climate-relevant sizes (diameters larger than 50–100 nm), where the particles may affect clouds and radiation. In this paper, we use one year of size-distribution measurements from Egbert, Ontario, Canada to calculate the frequency of regional-scale new-particle formation events, new-particle formation rates, growth rates and the fraction of new particles that survive to reach climate-relevant sizes. Regional-scale new-particle formation events occurred on 14–31% of the days (depending on the stringency of the classification criteria), with event frequency peaking in the spring and fall. New-particle formation rates and growth rates were similar to those measured at other mid-latitude continental sites. We calculate that roughly half of the climate-relevant particles (with diameters larger than 50–100 nm) at Egbert are formed through new-particle formation events. With the addition of meteorological and SO2 measurements, we find that new-particle formation often occurred under synoptic conditions associated with high surface pressure and large-scale subsidence that cause sunny conditions and clean-air flow from the north and west. However, new-particle formation also occurred when air flow came from the polluted regions to the south and southwest of Egbert. The nucleation rates tend to be faster during events under the polluted south/southwest flow conditions.

scholarly journals New-particle formation, growth and climate-relevant particle production in Egbert, Canada: analysis from 1 year of size-distribution observations

2014 ◽  
Vol 14 (16) ◽  
pp. 8647-8663 ◽  
Author(s):  
J. R. Pierce ◽  
D. M. Westervelt ◽  
S. A. Atwood ◽  
E. A. Barnes ◽  
W. R. Leaitch
Keyword(s):  
Size Distribution ◽  
Growth Rates ◽  
Large Scale ◽  
Particle Production ◽  
High Surface ◽  
Regional Scale ◽  
Particle Formation ◽  
Particle Nucleation ◽  
New Particle Formation ◽  
Synoptic Conditions

Abstract. Aerosol particle nucleation, or new-particle formation, is the dominant contributor to particle number in the atmosphere. However, these particles must grow through condensation of low-volatility vapors without coagulating with the larger, preexisting particles in order to reach climate-relevant sizes (diameters larger than 50–100 nm), where the particles may affect clouds and radiation. In this paper, we use 1 year of size-distribution measurements from Egbert, Ontario, Canada to calculate the frequency of regional-scale new-particle-formation events, new-particle-formation rates, growth rates and the fraction of new particles that survive to reach climate-relevant sizes. Regional-scale new-particle-formation events occur on 14–31% of the days (depending on the stringency of the classification criteria), with event frequency peaking in the spring and fall. New-particle-formation rates and growth rates are similar to those measured at other midlatitude continental sites. We calculate that roughly half of the climate-relevant particles (with diameters larger than 50–100 nm) at Egbert are formed through new-particle-formation events. With the addition of meteorological and SO2 measurements, we find that new-particle formation at Egbert often occurs under synoptic conditions associated with high surface pressure and large-scale subsidence that cause sunny conditions and clean-air flow from the north and west. However, new-particle formation also occurs when air flows from the polluted regions to the south and southwest of Egbert. The new-particle-formation rates tend to be faster during events under the polluted south/southwest flow conditions.

scholarly journals Modeling particle nucleation and growth over northern California during the 2010 CARES campaign

2015 ◽  
Vol 15 (21) ◽  
pp. 12283-12313 ◽  
Author(s):  
A. Lupascu ◽  
R. Easter ◽  
R. Zaveri ◽  
M. Shrivastava ◽  
M. Pekour ◽  
...  
Keyword(s):  
Size Distribution ◽  
Particle Number ◽  
Particle Formation ◽  
Number Concentration ◽  
Aerosol Size Distribution ◽  
Particle Nucleation ◽  
Particle Number Concentration ◽  
New Particle Formation ◽  
Organic Vapors ◽  
Diurnal Variability

Abstract. Accurate representation of the aerosol lifecycle requires adequate modeling of the particle number concentration and size distribution in addition to their mass, which is often the focus of aerosol modeling studies. This paper compares particle number concentrations and size distributions as predicted by three empirical nucleation parameterizations in the Weather Research and Forecast coupled with chemistry (WRF-Chem) regional model using 20 discrete size bins ranging from 1 nm to 10 μm. Two of the parameterizations are based on H2SO4, while one is based on both H2SO4 and organic vapors. Budget diagnostic terms for transport, dry deposition, emissions, condensational growth, nucleation, and coagulation of aerosol particles have been added to the model and are used to analyze the differences in how the new particle formation parameterizations influence the evolving aerosol size distribution. The simulations are evaluated using measurements collected at surface sites and from a research aircraft during the Carbonaceous Aerosol and Radiative Effects Study (CARES) conducted in the vicinity of Sacramento, California. While all three parameterizations captured the temporal variation of the size distribution during observed nucleation events as well as the spatial variability in aerosol number, all overestimated by up to a factor of 2.5 the total particle number concentration for particle diameters greater than 10 nm. Using the budget diagnostic terms, we demonstrate that the combined H2SO4 and low-volatility organic vapor parameterization leads to a different diurnal variability of new particle formation and growth to larger sizes compared to the parameterizations based on only H2SO4. At the CARES urban ground site, peak nucleation rates are predicted to occur around 12:00 Pacific (local) standard time (PST) for the H2SO4 parameterizations, whereas the highest rates were predicted at 08:00 and 16:00 PST when low-volatility organic gases are included in the parameterization. This can be explained by higher anthropogenic emissions of organic vapors at these times as well as lower boundary-layer heights that reduce vertical mixing. The higher nucleation rates in the H2SO4-organic parameterization at these times were largely offset by losses due to coagulation. Despite the different budget terms for ultrafine particles, the 10–40 nm diameter particle number concentrations from all three parameterizations increased from 10:00 to 14:00 PST and then decreased later in the afternoon, consistent with changes in the observed size and number distribution. We found that newly formed particles could explain up to 20–30 % of predicted cloud condensation nuclei at 0.5 % supersaturation, depending on location and the specific nucleation parameterization. A sensitivity simulation using 12 discrete size bins ranging from 1 nm to 10 μm diameter gave a reasonable estimate of particle number and size distribution compared to the 20 size bin simulation, while reducing the associated computational cost by ~ 36 %.

scholarly journals Quantifying aerosol size distributions and their temporal variability in the Southern Great Plains, USA

2019 ◽  
Vol 19 (18) ◽  
pp. 11985-12006 ◽  
Author(s):  
Peter J. Marinescu ◽  
Ezra J. T. Levin ◽  
Don Collins ◽  
Sonia M. Kreidenweis ◽  
Susan C. van den Heever
Keyword(s):  
Size Distribution ◽  
Great Plains ◽  
Diurnal Cycle ◽  
Particle Formation ◽  
Aerosol Size Distribution ◽  
Size Distributions ◽  
New Particle Formation ◽  
Scanning Mobility Particle Sizer ◽  
Southern Great Plains ◽  
Particle Sizer

Abstract. A quality-controlled, 5-year dataset of aerosol number size distributions (particles with diameters (Dp) from 7 nm through 14 µm) was developed using observations from a scanning mobility particle sizer, aerodynamic particle sizer, and a condensation particle counter at the Department of Energy's Southern Great Plains (SGP) site. This dataset was used for two purposes. First, typical characteristics of the aerosol size distribution (number, surface area, and volume) were calculated for the SGP site, both for the entire dataset and on a seasonal basis, and size distribution lognormal fit parameters are provided. While the median size distributions generally had similar shapes (four lognormal modes) in all the seasons, there were some significant differences between seasons. These differences were most significant in the smallest particles (Dp<30 nm) and largest particles (Dp>800 nm). Second, power spectral analysis was conducted on this long-term dataset to determine key temporal cycles of total aerosol concentrations, as well as aerosol concentrations in specified size ranges. The strongest cyclic signal was associated with a diurnal cycle in total aerosol number concentrations that was driven by the number concentrations of the smallest particles (Dp<30 nm). This diurnal cycle in the smallest particles occurred in all seasons in ∼50 % of the observations, suggesting a persistent influence of new particle formation events on the number concentrations observed at the SGP site. This finding is in contrast with earlier studies that suggest new particle formation is observed primarily in the springtime at this site. The timing of peak concentrations associated with this diurnal cycle was shifted by several hours depending on the season, which was consistent with seasonal differences in insolation and boundary layer processes. Significant diurnal cycles in number concentrations were also found for particles with Dp between 140 and 800 nm, with peak concentrations occurring in the overnight hours, which were primarily associated with both nitrate and organic aerosol cycles. Weaker cyclic signals were observed for longer timescales (days to weeks) and are hypothesized to be related to the timescales of synoptic weather variability. The strongest periodic signals (3.5–5 and 7 d cycles) for these longer timescales varied depending on the season, with no cyclic signals and the lowest variability in the summer.

scholarly journals Observation of aerosol size distribution and new particle formation at a mountain site in subtropical Hong Kong

2012 ◽  
Vol 12 (20) ◽  
pp. 9923-9939 ◽  
Author(s):  
H. Guo ◽  
D. W. Wang ◽  
K. Cheung ◽  
Z. H. Ling ◽  
C. K. Chan ◽  
...  
Keyword(s):  
Growth Rate ◽  
Hong Kong ◽  
Sulfuric Acid ◽  
Size Distribution ◽  
Formation Rate ◽  
Particle Formation ◽  
Aerosol Size Distribution ◽  
New Particle Formation ◽  
Average Growth ◽  
Nucleation Mode

Abstract. In order to investigate the formation and growth processes of nucleation mode particles, and to quantify the particle number (PN) concentration and size distributions in Hong Kong, an intensive field measurement was conducted from 25 October to 29 November in 2010 near the mountain summit of Tai Mo Shan, a suburban site approximately the geographical centre of the New Territories in Hong Kong. Based on observations of the particle size distribution, new particle formation (NPF) events were found on 12 out of 35 days with the estimated formation rate J5.5 from 0.97 to 10.2 cm−3 s−1, and the average growth rates from 1.5 to 8.4 nm h−1. The events usually began at 10:00–11:00 LT characterized by the occurrence of a nucleation mode with a peak diameter of 6–10 nm. Solar radiation, wind speed, sulfur dioxide (SO2) and ozone (O3) concentrations were on average higher, whereas temperature, relative humidity and daytime nitrogen dioxide (NO2) concentration were lower on NPF days than on non-NPF days. Back trajectory analysis suggested that in majority of the NPF event days, the air masses originated from the northwest to northeast directions. The concentrations of gaseous sulfuric acid (SA) showed good power-law relationship with formation rates, with exponents ranging from 1 to 2. The result suggests that the cluster activation theory and kinetic nucleation could potentially explain the observed NPF events in this mountainous atmosphere of Hong Kong. Meanwhile, in these NPF events, the contribution of sulfuric acid vapor to particle growth rate (GR5.5–25) ranged from 9.2 to 52.5% with an average of 26%. Measurement-based calculated oxidation rates of monoterpenes (i.e. α-pinene, β-pinene, myrcene and limonene) by O3 positively correlated with the GR5.5–25 (R = 0.80, p < 0.05). The observed associations of the estimated formation rate J5.5 and the growth rate GR5.5–25 with gaseous sulfuric acid and volatile organic compounds (VOCs) suggested the critical roles of sulfuric acid and biogenic VOCs (e.g. α-pinene and β-pinene) in these NPF events.

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