Preprints
https://doi.org/10.5194/acp-2021-994
https://doi.org/10.5194/acp-2021-994

  07 Dec 2021

07 Dec 2021

Review status: this preprint is currently under review for the journal ACP.

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

Lisa J. Beck1, Siegfried Schobesberger2, Heikki Junninen1,3, Janne Lampilahti1, Antti Manninen4, Lubna Dada1,5,6, Katri Leino1, Xu-Cheng He1, Iida Pullinen2, Lauriane Quéléver1, Anna Franck1, Pyry Poutanen1, Daniela Wimmer1, Frans Korhonen1, Mikko Sipilä1, Mikael Ehn1, Douglas Worsnop1,7, Veli-Matti Kerminen1, Tuukka Petäjä1,9, Markku Kulmala1,8,9,10, and Jonathan Duplissy1,11 Lisa J. Beck et al.
  • 1Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014 Helsinki, Finland
  • 2Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland
  • 3Institute of Physics, University of Tartu, Tartu, 50090, Estonia
  • 4Finnish Meteorological Institute, Helsinki, Finland
  • 5Extreme Environments Research Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL) Valais, Sion, 1951, Switzerland
  • 6Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, 5232, Switzerland
  • 7Aerodyne Research Inc., Billerica, MA, USA
  • 8Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Sciences and Engineering, Beijing University of Chemical Technology (BUCT), Beijing, China
  • 9Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing, China
  • 10Faculty of Geography, Lomonosov Moscow State University, Moscow, Russia
  • 11Helsinki Institute of Physics (HIP)/Physics, Faculty of Science, University of Helsinki, 00014 Helsinki, Finland

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.

Lisa J. Beck et al.

Status: open (until 09 Feb 2022)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Lisa J. Beck et al.

Lisa J. Beck et al.

Viewed

Total article views: 229 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
163 62 4 229 20 3 3
  • HTML: 163
  • PDF: 62
  • XML: 4
  • Total: 229
  • Supplement: 20
  • BibTeX: 3
  • EndNote: 3
Views and downloads (calculated since 07 Dec 2021)
Cumulative views and downloads (calculated since 07 Dec 2021)

Viewed (geographical distribution)

Total article views: 385 (including HTML, PDF, and XML) Thereof 385 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 18 Jan 2022
Download
Short summary
The presented article introduces an overview of atmospheric ions and their composition above the boreal forest. We provide the results of an extensive airborne measurement campaign with an air ion mass spectrometer and particle measurements, showing their diurnal behaviour within the boundary layer and free troposphere. In addition, we compare the airborne dataset with the co-located data from the ground at SMEAR II station, Finland.
Altmetrics