Aerosol particle formation in the upper residual layer

Lampilahti, Janne; Leino, Katri; Manninen, Antti; Poutanen, Pyry; Franck, Anna; Peltola, Maija; Hietala, Paula; Beck, Lisa; Dada, Lubna; Quéléver, Lauriane L. J.; Öhrnberg, Ronja; Zhou, Ying; Ekblom, Madeleine; Vakkari, Ville; Zilitinkevich, Sergej; Kerminen, Veli‐Matti; Petäj̈ä, Tuukka; Kulmala, Markku

doi:10.5194/acp-21-7901-2021

Cited by 21 publications

(19 citation statements)

References 49 publications

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“…The second setup consisted of a Neutral cluster and Air Ion Spectrometer (NAIS, Airel Ltd., Mirme and Mirme, 2013) for the last 2 flight days, measuring neutral particles between 2-40 nm and ions between 0.8-40 nm. Detailed information about the two setups can be found in Lampilahti et al (2021) and Leino et al (2019).…”

Section: Airborne Particle Measurementsmentioning

confidence: 99%

“…Furthermore, we were able to capture NPF in the upper part of the ML during the measurements. The NPF event has been discussed and published by Lampilahti et al (2021). With this case study, we aim to gain insight into the ion composition and how it developed in the different layers and throughout the day before and during the NPF event.…”

Section: Case Study 1: Diurnal Development Of Ion Composition In the Boundary Layermentioning

confidence: 99%

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Diurnal evolution of negative atmospheric ions above the boreal forest: From ground level to the free troposphere

Beck

Schobesberger

Junninen

et al. 2021

Preprint

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Abstract. At SMEAR II research station in Hyytiälä, located in the Finnish boreal forest, the process of new particle formation and the role of ions has been investigated for almost 20 years near the ground and at canopy level. However, above SMEAR II, the vertical distribution and diurnal variation of these different atmospheric ions are poorly characterized. In this study, we assess the atmospheric ion composition in the stable boundary layer, residual layer, mixing layer and free troposphere, and the 5 evolution of these atmospheric ions due to photochemistry and turbulent mixing through the day. To measure the vertical profile of atmospheric ions, we developed a tailored setup for online mass spectrometric measurements, capable of being deployed in a Cessna 172 with minimal modifications. Simultaneously, instruments dedicated to aerosol properties measured in a second Cessna. We conducted a total of 16 measurement flights in May 2017, during the spring, which is the most active new particle formation season. A flight day typically consisted of three distinct flights through the day (dawn, morning and afternoon) to 10 observe the diurnal variation and at different altitudes (from 100 m to 3200 m above ground), and to capture the boundary layer development from stable boundary layer, residual layer to mixing layer, and the free troposphere. Our observations showed that the ion composition is distinctly different in each layer and depends on the air mass origin and time of the day. Before sunrise, the layers are separated from each other and have their own ion chemistry. We observed that the ions present within the stable layer are of the same composition as the ions measured at the canopy level. During daytime when the mixing layer evolved and the compounds are vertically mixed, we observed that highly oxidised organic molecules are distributed to the top of the boundary layer. The ion composition in the residual layer varies with each day, showing similarities with either the stable boundary layer or the free troposphere. Finally, within the free troposphere, we detected a variety of carboxylic acids and ions that are likely containing halogens, originating from the Arctic Sea.

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Section: Airborne Particle Measurementsmentioning

confidence: 99%

Section: Case Study 1: Diurnal Development Of Ion Composition In the Boundary Layermentioning

confidence: 99%

Diurnal evolution of negative atmospheric ions above the boreal forest: From ground level to the free troposphere

Beck

Schobesberger

Junninen

et al. 2021

Preprint

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“…Data availability. Data used in this study are available from different sources: ground-based meteorological, radiation, gas and particle size distribution data from HTL (https://smear.avaa.csc.fi/; Junninen et al, 2009); the Cessna dataset (https://doi.org/10.5281/ zenodo.3688471; Lampilahti et al, 2020a); and the rest of the data (https://doi.org/10.5281/zenodo.4660145, Lampilahti et al, 2021b) are available. Competing interests.…”

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confidence: 99%

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

et al. 2021

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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.

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“…The maximum altitude was about 3800 m above sea level. More details about the set-up and measurements can be found in Schobesberger et al (2013), Leino et al (2019) and Lampilahti et al (2021a).…”

Section: Airborne In Situ Measurementsmentioning

confidence: 99%

“…The Ka-band data are available on request from Ewan O'Connor and HALO Doppler lidar MLH from Ville Vakkari. Airborne data can be found at https://doi.org/10.5281/zenodo.4063662 (Lampilahti et al, 2021b). The ERA5 data set was downloaded from https: //cds.climate.copernicus.eu/cdsapp#!/home (last access: 25 February 2020, Copernicus Climate Change , 2017) and chosen for the grid point closest to the Hyytiälä station.…”

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confidence: 99%

Evaluation of convective boundary layer height estimates using radars operating at different frequency bands

et al. 2021

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Abstract. Knowledge of the atmospheric boundary layer state and evolution is important for understanding air pollution and low-level cloud development, among other things. There are a number of instruments and methods that are currently used to estimate boundary layer height (BLH). However, no single instrument is capable of providing BLH measurements in all weather conditions. We proposed a method to derive a daytime convective BLH using clear air echoes in radar observations and investigated the consistency of these retrievals between different radar frequencies. We utilized data from three vertically pointing radars that are available at the SMEAR II station in Finland, i.e. the C band (5 GHz), Ka band (35 GHz) and W band (94 GHz). The Ka- or W-band cloud radars are an integral part of cloud profiling stations of pan-European Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS). Our method will be utilized at ACTRIS stations to serve as an additional estimate of the BLH during summer months. During this period, insects and Bragg scatter are often responsible for clear air echoes recorded by weather and cloud radars. To retrieve a BLH, we suggested a mechanism to separate passive and independently flying insects that works for all analysed frequency bands. At the lower frequency (the C band) insect scattering has been separated from Bragg scattering using a combination of the radar reflectivity factor and linear depolarization ratio. Retrieved values of the BLH from all radars are in a good agreement when compared to the BLH obtained with the co-located HALO Doppler lidar and ERA5 reanalysis data set. Our method showed some underestimation of the BLH after nighttime heavy precipitation yet demonstrated a potential to serve as a reliable method to obtain a BLH during clear-sky days. Additionally, the entrainment zone was observed by the C-band radar above the CBL in the form of a Bragg scatter layer. Aircraft observations of vertical profiles of potential temperature and water vapour concentration, collected in the vicinity of the radar, demonstrated some agreement with the Bragg scatter layer.

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Aerosol particle formation in the upper residual layer

Cited by 21 publications

References 49 publications

Diurnal evolution of negative atmospheric ions above the boreal forest: From ground level to the free troposphere

Diurnal evolution of negative atmospheric ions above the boreal forest: From ground level to the free troposphere

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

Evaluation of convective boundary layer height estimates using radars operating at different frequency bands

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