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.

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 New Particle Formation and impact on CCN concentrations in the boundary layer and free troposphere at the high altitude station of Chacaltaya (5240 m a.s.l.), Bolivia

2016 ◽  
Author(s):  
C. Rose ◽  
K. Sellegri ◽  
I. Moreno ◽  
F. Velarde ◽  
M. Ramonet ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Particle Number ◽  
Particle Growth ◽  
Particle Formation ◽  
Number Concentration ◽  
Particle Number Concentration ◽  
Free Troposphere ◽  
New Particle Formation ◽  
Radiative Processes ◽  
The Impact

Abstract. Global models predict that new particle formation (NPF) is, in some environments, responsible for a substantial fraction of the total atmospheric particle number concentration and subsequently contribute significantly to cloud condensation nuclei (CCN) concentrations. NPF events were frequently observed at the highest atmospheric observatory in the world, Chacaltaya (5240 m a.s.l.), Bolivia. The present study focuses on the impact of NPF on CCN population. Neutral cluster and Air Ion Spectrometer and mobility particle size spectrometer measurements were simultaneously used to follow the growth of particles from cluster sizes down to ~ 2 nm up to CCN threshold sizes set to 50, 80 and 100 nm. Using measurements performed between January 1 and December 31 2012, we found that 61% of the 94 analysed events showed a clear particle growth and significant enhancement of the CCN-relevant particle number concentration. We evaluated the contribution of NPF events relative to the transport of pre-existing particles to the site. The averaged production of 50 nm particles during those events was 5072 cm−3, and 1481 cm−3 for 100 nm particles, with a larger contribution of NPF compared to transport, especially during the wet season. The data set was further segregated into boundary layer (BL) and free troposphere (FT) conditions at the site. The NPF frequency of occurrence was higher in the BL (48 %) compared to the FT (39 %). Particle condensational growth was more frequently observed for events initiated in the FT, but on average faster for those initiated in the BL, when the amount of condensable species was most probably larger. As a result, the potential to form new CCN was higher for events initiated in the BL (67 % against 56 % in the FT). In contrast, higher CCN number concentration increases were found when the NPF process initially occurred in the FT, under less polluted conditions. This work highlights the competition between particle growth and the removal of freshly nucleated particles by coagulation processes. The results support model predictions which suggest that NPF is an effective source of CCN in some environments, and thus may influence regional climate through cloud related radiative processes.

Does the onset of new particle formation occur in the planetary boundary layer?

2013 ◽  
Author(s):  
Hanna E. Manninen ◽  
Sander Mirme ◽  
Mikael Ehn ◽  
Katri Leino ◽  
Siegfried Schobesberger ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Particle Formation ◽  
New Particle Formation

scholarly journals The link between atmospheric radicals and newly formed particles at a spruce forest site in Germany

2014 ◽  
Vol 14 (19) ◽  
pp. 10823-10843 ◽  
Author(s):  
B. Bonn ◽  
E. Bourtsoukidis ◽  
T. S. Sun ◽  
H. Bingemer ◽  
L. Rondo ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Inorganic Compounds ◽  
Empirical Relationship ◽  
Particle Formation ◽  
Climate Feedback ◽  
Activation Process ◽  
Forest Site ◽  
Peroxy Radicals ◽  
New Particle Formation ◽  
The Impact

Abstract. It has been claimed for more than a century that atmospheric new particle formation is primarily influenced by the presence of sulfuric acid. However, the activation process of sulfuric acid related clusters into detectable particles is still an unresolved topic. In this study we focus on the PARADE campaign measurements conducted during August/September 2011 at Mt Kleiner Feldberg in central Germany. During this campaign a set of radicals, organic and inorganic compounds and oxidants and aerosol properties were measured or calculated. We compared a range of organic and inorganic nucleation theories, evaluating their ability to simulate measured particle formation rates at 3 nm in diameter (J3) for a variety of different conditions. Nucleation mechanisms involving only sulfuric acid tentatively captured the observed noon-time daily maximum in J3, but displayed an increasing difference to J3 measurements during the rest of the diurnal cycle. Including large organic radicals, i.e. organic peroxy radicals (RO2) deriving from monoterpenes and their oxidation products, in the nucleation mechanism improved the correlation between observed and simulated J3. This supports a recently proposed empirical relationship for new particle formation that has been used in global models. However, the best match between theory and measurements for the site of interest was found for an activation process based on large organic peroxy radicals and stabilised Criegee intermediates (sCI). This novel laboratory-derived algorithm simulated the daily pattern and intensity of J3 observed in the ambient data. In this algorithm organic derived radicals are involved in activation and growth and link the formation rate of smallest aerosol particles with OH during daytime and NO3 during night-time. Because the RO2 lifetime is controlled by HO2 and NO we conclude that peroxy radicals and NO seem to play an important role for ambient radical chemistry not only with respect to oxidation capacity but also for the activation process of new particle formation. This is supposed to have significant impact of atmospheric radical species on aerosol chemistry and should be taken into account when studying the impact of new particles in climate feedback cycles.

scholarly journals Investigating the importance of sub-grid particle formation in point source plumes over eastern China using IAP-AACM v1.0 with a sub-grid parameterization

2021 ◽  
Vol 14 (7) ◽  
pp. 4411-4428
Author(s):  
Ying Wei ◽  
Xueshun Chen ◽  
Huansheng Chen ◽  
Yele Sun ◽  
Wenyi Yang ◽  
...  
Keyword(s):  
Point Source ◽  
Transport Model ◽  
Aerosol Particles ◽  
Eastern China ◽  
Regional Scale ◽  
Chemical Transport ◽  
Particle Formation ◽  
Point Sources ◽  
Formation Processes ◽  
New Particle Formation

Abstract. The influence of sub-grid particle formation (SGPF) in point source plumes on aerosol particles over eastern China was firstly illustrated by implementing an SGPF scheme into a global–regional nested chemical transport model with an aerosol microphysics module. The key parameter in the scheme was optimized based on the observations in eastern China. With the parameterization of SGPF, the spatial heterogeneity and diurnal variation in particle formation processes in sub-grid scale were well resolved. The SGPF scheme can significantly improve the model performance in simulating aerosol components and new particle formation processes at typical sites influenced by point sources. The comparison with observations at Beijing, Wuhan and Nanjing showed that the normal mean bias (NMB) of sulfate and ammonium could be reduced by 23 %–27 % and 12 %–14 %, respectively. When wind fields are well reproduced, the correlation of sulfate between simulation and observation can be increased by 0.13 in Nanjing. Considering the diurnal cycle of new particle formation, the SGPF scheme can greatly reduce the overestimation of particle number concentration in nucleation and Aitken mode at night caused by fixed-fraction parameterization of SGPF. On the regional scale, downwind areas of point source experienced an increase in sulfate concentration of 25 %–50 %. The results of this study indicate the significant effects of SGPF on aerosol particles over areas with the point source and the necessity of a reasonable representation of SGPF processes in chemical transport models.

scholarly journals Large difference in aerosol radiative effects from BVOC-SOA treatment in three ESMs

2020 ◽  
Author(s):  
Moa K. Sporre ◽  
Sara M. Blichner ◽  
Roland Schrödner ◽  
Inger H. H. Karset ◽  
Terje K. Berntsen ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
Particle Formation ◽  
Earth System ◽  
New Particle Formation ◽  
Aerosol Formation ◽  
Radiative Effects ◽  
Sensitivity Experiments ◽  
Aerosol Radiative Effects ◽  
The Impact ◽  
Aerosol Radiative

Abstract. Biogenic volatile organic compounds (BVOCs) emitted from vegetation are oxidized in the atmosphere and can form aerosol particles either by contributing to new particle formation or by condensing onto existing aerosol particles. As the understanding of the importance of BVOCs for aerosol formation has increased over the past 10 years these processes have made their way into Earth System Models (ESMs). In this study, sensitivity experiments are run with three different ESMs, (the Norwegian Earth System Model (NorESM), EC-Earth and ECHAM) to investigate how the direct and indirect aerosol radiative effects are affected by changes in the formation of secondary organic aerosol (SOA) from BVOCs. In the first two sensitivity model experiments, the yields of SOA precursors from oxidation of BVOCs are changed by ± 50 %. For the third sensitivity test, the formed oxidation products do not participate in the formation of new particles, but are only allowed to condense onto existing aerosols. In the last two sensitivity experiments, the emissions of BVOC compounds (isoprene and monoterpenes) are turned off, one at a time. The results show that the impact on the direct radiative effect (DRE) are linked to the changes in the SOA production in the models, where more SOA leads to a stronger DRE and vice versa. The magnitude by which the DRE changes (maximally 0.15 W m−2 globally averaged) in response to the SOA changes however varies between the models, with EC-Earth displaying the largest changes. The results for the cloud radiative effects (CRE) are more complicated than for the DRE. The changes in CRE differ more among the ESMs and for some sensitivity experiments they even have different signs. The most sensitive models are NorESM and EC-Earth, which has CRE changes of up to 0.82 W m−2. The varying responses in the different models are connected to where in the aerosol size distributions the changes in mass and number due to SOA formation occur, in combination with the aerosol number concentration levels in the models. We also find that interactive gas-phase chemistry as well as the new particle formation parameterization have important implications for the DRE and CRE in some of the sensitivity experiments. The results from this study indicate that BVOC-SOA treatment in ESMs can have a substantial impact on the modelled climate but that the sensitivity varies greatly between the models. Since BVOC emissions have changed historically and will continue to change in the future, the spread in model results found in this study introduces uncertainty into ESM estimates of aerosol forcing from land-use change and BVOC feedback strengths.

scholarly journals Zeppelin-led study on the onset of new particle formation in the planetary boundary layer

2021 ◽  
Vol 21 (16) ◽  
pp. 12649-12663
Author(s):  
Janne Lampilahti ◽  
Hanna E. Manninen ◽  
Tuomo Nieminen ◽  
Sander Mirme ◽  
Mikael Ehn ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Particle Formation ◽  
New Particle Formation ◽  
Subsequent Growth ◽  
Local Enhancement ◽  
Urban Background ◽  
Airborne Measurements ◽  
Po Valley ◽  
Different Parts

Abstract. We compared observations of aerosol particle formation and growth in different parts of the planetary boundary layer at two different environments that have frequent new particle formation (NPF) events. In summer 2012 we had a campaign in Po Valley, Italy (urban background), and in spring 2013 a similar campaign took place in Hyytiälä, Finland (rural background). Our study consists of three case studies of airborne and ground-based measurements of ion and particle size distribution from ∼1 nm. The airborne measurements were performed using a Zeppelin inside the boundary layer up to 1000 m altitude. Our observations show the onset of regional NPF and the subsequent growth of the aerosol particles happening almost uniformly inside the mixed layer (ML) in both locations. However, in Hyytiälä we noticed local enhancement in the intensity of NPF caused by mesoscale boundary layer (BL) dynamics. Additionally, our observations indicate that in Hyytiälä NPF was probably also taking place above the ML. In Po Valley we observed NPF that was limited to a specific air mass.

scholarly journals Observations of turbulence-induced new particle formation in the residual layer

2010 ◽  
Vol 10 (1) ◽  
pp. 327-360 ◽  
Author(s):  
B. Wehner ◽  
H. Siebert ◽  
A. Ansmann ◽  
F. Ditas ◽  
P. Seifert ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Ultrafine Particles ◽  
Vertical Mixing ◽  
Ground Level ◽  
Particle Formation ◽  
Residual Layer ◽  
New Particle Formation ◽  
Boundary Layer Development ◽  
Critical Richardson Number ◽  
The Impact

Abstract. Aerosol particle measurements in the atmospheric boundary layer performed by a helicopter-borne measurement payload and by a lidar system from a case study during the IMPACT field campaign in Cabauw (NL) are presented. Layers of increased number concentrations of ultrafine particles were observed in the residual layer, indicating relatively recent new-particle formation. These layers were characterized by a sub-critical Richardson number and concomitant increased turbulence. Turbulent mixing is likely to lead to local supersaturation of possible precursor gases which are essential for new particle formation. Observed peaks in the number concentrations of ultrafine particles at ground level are connected to the new particle formation in the residual layer by boundary layer development and vertical mixing.

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