Vertical profiles of sub-3 nm particles over the boreal forest

Leino, Katri; Lampilahti, Janne; Poutanen, Pyry; Väänänen, Riikka; Manninen, Antti; Mazon, Stephany Buenrostro; Dada, Lubna; Franck, Anna; Wimmer, Daniela; Aalto, Pasi; Ahonen, Lauri; Enroth, Joonas; Kangasluoma, Juha; Keronen, Petri; Korhonen, Frans; Laakso, H.; Matilainen, Teemu; Siivola, Erkki; Manninen, Hanna E.; Lehtipalo, Katrianne; Kerminen, Veli‐Matti; Petäj̈ä, Tuukka; Kulmala, Markku

doi:10.5194/acp-19-4127-2019

Cited by 32 publications

(43 citation statements)

References 34 publications

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“…On the other hand, if the 2 -4 nm ions are present but they do not grow to form 7 -25 nm particles, the time period is classified as an ion burst (IB). Moreover, if 2 -4 nm ions are not present, but we observe an increase in the particles, this leads to the assumption that the NPF event did not occur at the measurement location but was carried horizontally or vertically to our site (Leino et al, 2018). The latter has been previously described as a tail event (Buenrostro Mazon et al, 2009) or a transported event (TE).…”

Section: Event Classification Decision Treementioning

confidence: 82%

Refined classification and characterization of atmospheric new particle formation events using air ions

Dada¹,

Chellapermal²,

Mazon³

et al. 2018

Preprint

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<p><strong>Abstract.</strong> Atmospheric new particle formation (NPF) is a world-wide observed phenomenon that affects the human health and the global climate. With the growing network of global atmospheric measurement stations, efforts towards investigating NPF have increased. In this study, we present an automated method to classify days into four categories including NPF events, non-events and two classes in between, which then ensures the reproducibility and minimizes the man-hours spent on manual classification. We applied our automated method to 10 years of data collected at the SMEAR II measurement station in Hyyti&#228;l&#228;, southern Finland. In contrast to the traditionally-applied classification methods which categorize days into events, non-events and ambiguous days as undefined days, our method is able to classify the undefined days as it accesses the initial steps of NPF at sub-3&#8201;nm sizes. Our results show that on ~&#8201;24&#8201;% of the days in Hyyti&#228;l&#228;, a regional NPF event occurred and was characterized by a <q>nice weather</q> and favorable conditions such as a clear sky and low condensation sink. Another class found in Hyyti&#228;l&#228; is the transported event class, which seems to be NPF carried horizontally or vertically to our measurement location and it occurred on 17&#8201;% of the total studied days. Additionally, we found that an ion burst, where the ions apparently fail to grow to larger sizes, occurred on 18&#8201;% of the days in Hyyti&#228;l&#228;. The transported events and ion bursts were characterized by less favorable ambient conditions than regional NPF events, and thus experienced interrupted particle formation or growth. Non-events occurred on 41&#8201;% of the days and were characterized by a complete cloud cover and high relative humidity. Moreover, for the regional NPF events occurring at the measurement site, the method identifies the start time, peak time and end time, which helps us focus on variables within an exact time window to better understand NPF in a process level. Our automated method can be modified to work in other measurement locations where NPF is observed.</p>

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Section: Event Classification Decision Treementioning

confidence: 82%

Refined classification and characterization of atmospheric new particle formation events using air ions

Dada¹,

Chellapermal²,

Mazon³

et al. 2018

Preprint

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“…The nanoparticle concentrations were the highest at the elevation closest to the surface, but high number concentrations were observed at altitudes up to 500 m. High nanoparticle concentrations in the residual layer has been observed in different environments as well (e.g. Wehner et al, 2010;Altstädter et al, 2018, Leino et al, 2019Carnerero et al, 2019).…”

Section: Vertical Measurements Of Aerosol Particle Number Concentratimentioning

confidence: 93%

“…Campaign that was organized at the station from February to September 2014. A Scanning Mobility Particle Sizer (SMPS) and Optical Particle Sizer (OPS) were installed onboard Cessna FR172F aircraft (Schobesberger et al, 2013, Leino et al 2019 to measure aerosol size distribution from 0.1 to 0.23 µm and 0.3 to 5 µm, respectively. The flights 805 were conducted in the vicinity of the station not higher than 4 km in altitude with relatively low speed of 200 km/h, thus, providing observations with good spatial resolution.…”

Section: Finlandmentioning

confidence: 99%

Integrative and comprehensive Understanding on Polar Environments (iCUPE): the concept and initial results

Petäj̈ä¹,

Duplissy²,

Tabakova³

et al. 2020

Preprint

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The role of polar regions increases in terms of megatrends such as globalization, new transport routes, demography and use of natural resources consequent effects of regional and transported pollutant concentrations. We set up the ERA-PLANET Strand 4 project "iCUPE -integrative and Comprehensive Understanding on Polar Environments" to provide novel insights and observational data on global grand challenges with an Arctic focus. We utilize an integrated approach combining 55 in situ observations, satellite remote sensing Earth Observations (EO) and multi-scale modeling to synthesize data from comprehensive long-term measurements, intensive campaigns and satellites to deliver data products, metrics and indicators to the stakeholders concerning the environmental status, availability and extraction of natural resources in the polar areas. The iCUPE work consists of thematic state-of-the-art research and provision of novel data in atmospheric pollution, local sources and transboundary transport, characterization of arctic surfaces and their changes, assessment of concentrations and impacts 60 of heavy metals and persistent organic pollutants and their cycling, quantification of emissions from natural resource extraction and validation and optimization of satellite Earth Observation (EO) data streams. In this paper we introduce the iCUPE project and summarize initial results arising out of integration of comprehensive in situ observations, satellite remote sensing and multiscale modeling in the Arctic context. 65

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“…The University of Helsinki has organized several airborne measurement campaigns around Hyytiälä using an instrumented Cessna 172 airplane. Descriptions of the measurement setups can be found in previous works (Leino et al, 2019;Schobesberger et al, 2013;Väänänen et al, 2016). Table 1 shows a summary of the airborne measurement campaigns and the instrumentation from which data was used in this study.…”

Section: Airplane Measurementsmentioning

confidence: 99%

“…For example inside the residual layer (Wehner et al, 2010) and in the inversion capping a shallow mixed layer (Platis et al, 2015;Siebert et al, 2004). Other airborne measurements have found significant horizontal and vertical variability in the number concentration of nucleation mode particles within the BL (Crumeyrolle et al, 2010;Leino et al, 2019;O'Dowd et al, 2009;Schobesberger et al, 2013;Väänänen et al, 2016). One possible reason for this could be the effect of bounadry layer (BL) dynamics.…”

Section: Introductionmentioning

confidence: 99%

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

Lampilahti¹,

Manninen²,

Leino³

et al. 2020

Preprint

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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.

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Vertical profiles of sub-3 nm particles over the boreal forest

Cited by 32 publications

References 34 publications

Refined classification and characterization of atmospheric new particle formation events using air ions

Refined classification and characterization of atmospheric new particle formation events using air ions

Integrative and comprehensive Understanding on Polar Environments (iCUPE): the concept and initial results

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

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