Aerosol and Cloud Chemistry  --  Projects

LExNo
(LACIS Experiment in November)

           

This project, which was performed in November 2005 at the LACIS facility of IfT Leipzig, aims at determining the hygroscopic growth and activation of model substances, representing wood burning aerosol particles, with several measurement techniques. For this, soot particles were coated with an inorganic salt (ammonium sulphate) and/or with an organic compound (levoglucosan). Also, the ability of aerosol mass spectrometers (AMS) to distinguish between soot and organic material in the particles was tested.
An important part of the LACIS infrastructure site is the particle production unit which allows producing well defined particles either pure or coated with inorganic or organic substances with known layer thickness. Depending on the experimental aim monodisperse or polydisperse particles can be synthesised.
Chemical characterisation of the artificial particles was conducted with two AMS with special focus on the retrieval of the organic substance patterns and soot detection.
The hygroscopic growth of the coated soot particles was be characterised with two different techniques: (a) LACIS, which was used in the humidity range between 90 up to 99% and (b) an Hygroscopic Tandem Differential Mobility Analyser (HTDMA) that can be used up to 98%. The particles critical super-saturation were determined by (a) a static thermal diffusion chamber (CCNC-100B), (b) a continuous-flow streamwise thermal-gradient CCN chamber (Scripps type), and (c) LACIS.

Collaboration with IfT Leipzig (F. Stratmann, H. Wex), Biogeochemistry Dept. of MPI-C (D. Rose, G. Frank), Univ. Copenhagen (M. Bilde, A. Kristensson), Univ. Wyoming (J. Snider), FZ Jülich (T. Mentel, A. Kiendler-Scharr)

Instrumentation:
Aerodyne Q-AMS, TSI CPC 3025a

People involved:
S. Walter, J. Schneider

Results:

Kiselev, A., C. Wennrich, F. Stratmann, H. Wex, S. Henning, Th. F. Mentel, A. Kiendler-Scharr, J. Schneider, S. Walter, and I. Lieberwirth (2010), Morphological characterization of soot aerosol particles during LExNo,  J. Geophys. Res., 115, D11204, doi:10.1029/2009JD012635, 2010.

Henning, S., H. Wex, T. Hennig, A. Kiselev, J. Snider, D. Rose, U. Dusek, G. P. Frank, U. Pöschl, A. Kristensson, M. Bilde, R. Tillmann, A. Kiendler-Scharr, Th. F. Mentel, S. Walter, J. Schneider, C. Wennrich, and F. Stratmann, Soluble mass, hygroscopic growth and droplet activation of coated soot particles during LExNo,
J. Geophys. Res., 115, D11206, doi:10.1029/2009JD012626, 2010.

Stratmann, F., M. Bilde, U. Dusek, G. Frank, T. Hennig, S. Henning, A. Kiendler-Scharr, A. Kiselev, A. Kristensson, I. Lieberwirt, Th. F. Mentel, U. Pöschl, D. Rose, J. Schneider, J. Snider, R. Tillmann, S. Walter, and H.Wex, Examination of Laboratory-Generated Coated Soot Particles: An Overview over the LExNo Campaign, J.Geophys.Res., 115, D11203, doi:10.1029/2009JD012628, 2010.