Title Chemical composition of ambient aerosol, ice residues and cloud droplet residues in mixed-phase clouds; single particle analysis during the Cloud and Aerosol Characterization Experiment (CLACE 6)
Author Kamphus, M.; Ettner-Mahl, M.; Klimach, T.; Drewnick, F.; Keller, L.; Cziczo, D.J.; Mertes, S.; Borrmann, S.; Curtius, J.
Author Affil Kamphus, M., Johannes Gutenberg- Universität Mainz, Institut für Physik der Atmosphäre, Mainz, Germany. Other: Max-Planck- Institut für Chemie, Germany; Eidgenössiche Technische Hochschule Zürich, Switzerland; Leibniz-Institüt für Troposphärenforschung, Germany
Source Atmospheric Chemistry and Physics, 10(16), p.8077-8095, . Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1680- 7316
Publication Date 2010
Notes In English. Part of special issue no. 132, Cloud, aerosol, ice and snow characterizations within the CLACE experiments at the high alpine research station Jungfraujoch, edited by Weingartner, E., et al., http://www.atmos-chem- phys.net/special_issue132.html; published in Atmospheric Chemistry and Physics Discussions: 17 July 2009, http://www.atmos- chem-phys-discuss.net/9/15375/2009/acpd-9- 15375-2009.html ; accessed in June, 2011. 67 refs. GeoRef Acc. No: 310020
Index Terms aerosols; aluminum; chemical composition; clouds (meteorology); cooling; crystals; ice; ice crystals; liquid phases; liquid cooling; metals; remote sensing; spectra; alkali metals; alkaline earth metals; aluminosilicates; atmosphere; calcium; calcium oxide; carbon; Cloud and Aerosol Characterization Experiment; clouds; droplets; insoluble residues; iron; liquid phase; mass spectra; organic compounds; potassium; silica; silicates; sulfates; sulfur
Abstract Two different single particle mass spectrometers were operated in parallel at the Swiss High Alpine Research Station Jungfraujoch (JFJ, 3580 m a.s.l.) during the Cloud and Aerosol Characterization Experiment (CLACE 6) in February and March 2007. During mixed phase cloud events ice crystals from 5- 20 µm were separated from larger ice aggregates, non-activated, interstitial aerosol particles and supercooled droplets using an Ice-Counterflow Virtual Impactor (Ice-CVI). During one cloud period supercooled droplets were additionally sampled and analyzed by changing the Ice-CVI setup. The small ice particles and droplets were evaporated by injection into dry air inside the Ice-CVI. The resulting ice and droplet residues (IR and DR) were analyzed for size and composition by the two single particle mass spectrometers: a custom-built Single Particle Laser-Ablation Time-of-Flight Mass Spectrometer (SPLAT) and a commercial Aerosol Time-of-Flight Mass Spectrometer (ATOFMS, TSI Model 3800). During CLACE 6 the SPLAT instrument characterized 355 individual IR that produced a mass spectrum for at least one polarity and the ATOFMS measured 152 IR. The mass spectra were binned in classes, based on the combination of dominating substances, such as mineral dust, sulfate, potassium and elemental carbon or organic material. The derived chemical information from the ice residues is compared to the JFJ ambient aerosol that was sampled while the measurement station was out of clouds (several thousand particles analyzed by SPLAT and ATOFMS) and to the composition of the residues of supercooled cloud droplets (SPLAT: 162 cloud droplet residues analyzed, ATOFMS: 1094). The measurements showed that mineral dust was strongly enhanced in the ice particle residues. Close to all of the SPLAT spectra from ice residues did contain signatures from mineral compounds, albeit connected with varying amounts of soluble compounds. Similarly, close to all of the ATOFMS IR spectra show a mineral or metallic component. Pure sulfate and nitrate containing particles were depleted in the ice residues. Sulfate and nitrate was found to dominate the droplet residues (~90% of the particles). The results from the two different single particle mass spectrometers were generally in agreement. Differences in the results originate from several causes, such as the different wavelength of the desorption and ionisation lasers and different size-dependent particle detection efficiencies.
URL http://www.atmos-chem-phys.net/10/8077/2010/acp-10-8077-2010.pdf
Publication Type journal article
Record ID 65006832