Preprints
https://doi.org/10.5194/egusphere-2023-439
https://doi.org/10.5194/egusphere-2023-439
19 Apr 2023
 | 19 Apr 2023

Characterization of the airborne aerosol inlet and transport system used during the A-LIFE aircraft field experiment

Manuel Schöberl, Maximilian Dollner, Josef Gasteiger, Petra Seibert, Anne Tipka, and Bernadett Weinzierl

Abstract. Atmospheric aerosol particles have a profound impact on Earth’s climate by scattering and absorbing solar and terrestrial radiation and by impacting the properties of clouds. Research aircraft such as the Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) Falcon are widely used to study aerosol particles in the troposphere and lower stratosphere. However, transporting a representative sample to the instrumentation inside the aircraft remains a challenge due to high airspeeds and changing ambient conditions. In particular, for high-quality coarse mode aerosol measurements, knowledge about losses or enhancements in the aerosol sampling system is crucial. In this study, we present a detailed characterization of the Falcon aerosol sampling system. Aerosol number size distributions were measured during the A-LIFE field campaign simultaneously with in-cabin and out-cabin/wing-mounted instrumentation. Sampling efficiencies were derived for different true airspeed ranges by comparing the in-cabin and the out-cabin particle number size distributions during flight sequences with a major contribution of mineral dust particles in the coarse mode size range. Additionally, experimentally derived Stokes numbers were used to calculate the cut-off diameter of the A-LIFE aerosol sampling system for different particle densities as a function of true airspeed. The results show that the velocity of the research aircraft has a major impact on the sampling of coarse mode aerosol particles with in-cabin instruments. For true airspeeds up to about 190 m s-1, aerosol particles larger than about 1 µm are depleted in the sampling system of the Falcon during the A-LIFE project. In contrast, for true airspeeds higher than 190 m s-1, an enhancement of particles up to a diameter of 4 µm is observed. For even larger particles, the enhancement effect at the inlet is still present, but inertial and gravitational particle losses in the transport system get more and more pronounced which leads to a decreasing overall sampling efficiency. In summary, aerosol particles can either be depleted or enhanced at an aerosol inlet, whereas transport in sampling lines always leads to a loss of particles. Therefore, it is important to consider both, inlet and transport efficiency, when quantifying the sampling efficiency of an aerosol sampling system.

Manuel Schöberl, Maximilian Dollner, Josef Gasteiger, Petra Seibert, Anne Tipka, and Bernadett Weinzierl

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-439', Darrel Baumgardner, 24 Jun 2023
    • AC2: 'Reply on RC1', Bernadett Weinzierl, 15 Nov 2023
  • RC2: 'Comment on egusphere-2023-439', Anonymous Referee #2, 20 Jul 2023
    • AC1: 'Reply on RC2', Bernadett Weinzierl, 14 Nov 2023
Manuel Schöberl, Maximilian Dollner, Josef Gasteiger, Petra Seibert, Anne Tipka, and Bernadett Weinzierl
Manuel Schöberl, Maximilian Dollner, Josef Gasteiger, Petra Seibert, Anne Tipka, and Bernadett Weinzierl

Viewed

Total article views: 684 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
462 192 30 684 71 16 18
  • HTML: 462
  • PDF: 192
  • XML: 30
  • Total: 684
  • Supplement: 71
  • BibTeX: 16
  • EndNote: 18
Views and downloads (calculated since 19 Apr 2023)
Cumulative views and downloads (calculated since 19 Apr 2023)

Viewed (geographical distribution)

Total article views: 679 (including HTML, PDF, and XML) Thereof 679 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 26 Feb 2024
Download
Short summary
Transporting a representative aerosol sample to instrumentation inside a research aircraft remains a challenge due to losses or enhancements of particles in the aerosol sampling system. Here, we present sampling efficiencies and the cut-off diameter for the DLR Falcon aerosol sampling system as a function of true airspeed by comparing the in-cabin and the out-cabin particle number size distributions observed during the A-LIFE aircraft mission.