Size-resolved morphological properties of the high Arctic summer aerosol during ASCOS-2008
The representation of aerosol properties and processes in climate models is fraught with large uncertainties. Especially at high northern latitudes a strong underprediction of aerosol concentrations and nucleation events is observed and can only be constrained by in situ observations based on th...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2016-05-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/6577/2016/acp-16-6577-2016.pdf |
| _version_ | 1819267911657717760 |
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| author | E. Hamacher-Barth C. Leck K. Jansson |
| author_facet | E. Hamacher-Barth C. Leck K. Jansson |
| author_sort | E. Hamacher-Barth |
| collection | DOAJ |
| description | The representation of aerosol properties and processes in climate
models is fraught with large uncertainties. Especially at high northern
latitudes a strong underprediction of aerosol concentrations and nucleation
events is observed and can only be constrained by in situ observations based
on the analysis of individual aerosol particles. To further reduce the
uncertainties surrounding aerosol properties and their potential role as
cloud condensation nuclei this study provides observational data resolved
over size on morphological and chemical properties of aerosol particles
collected in the summer high Arctic, north of 80° N.<br><br>
Aerosol particles were imaged with scanning and transmission electron
microscopy and further evaluated with digital image analysis. In total, 3909
aerosol particles were imaged and categorized according to morphological
similarities into three gross morphological groups: single particles, gel
particles, and halo particles. Single particles were observed between 15 and
800 nm in diameter and represent the dominating type of particles (82 %).
The majority of particles appeared to be marine gels with a broad Aitken mode
peaking at 70 nm and accompanied by a minor fraction of ammonium (bi)sulfate
with a maximum at 170 nm in number concentration. Gel particles (11 % of
all particles) were observed between 45 and 800 nm with a maximum at 154 nm
in diameter. Imaging with transmission electron microscopy
allowed further morphological discrimination of gel particles in
"aggregate" particles, "aggregate with film" particles, and
"mucus-like" particles.<br><br>
Halo particles were observed above 75 nm and appeared to be ammonium
(bi)sulfate (59 % of halo particles), gel matter (19 %), or decomposed gel
matter (22 %), which were internally mixed with sulfuric acid, methane
sulfonic acid, or ammonium (bi)sulfate with a maximum at 161 nm in diameter.<br><br>
Elemental dispersive X-ray spectroscopy analysis of individual particles
revealed a prevalence of the monovalent ions Na<sup>+</sup>/K<sup>+</sup> for single
particles and aggregate particles and of the divalent ions
Ca<sup>2+</sup>/Mg<sup>2+</sup> for aggregate with film particles and
mucus-like particles. According to these results and other model
studies, we propose a relationship between the availability of
Na<sup>+</sup>/K<sup>+</sup> and Ca<sup>2+</sup>/Mg<sup>2+</sup> and the length of the biopolymer
molecules participating in the formation of the three-dimensional gel networks. |
| first_indexed | 2024-12-23T21:24:41Z |
| format | Article |
| id | doaj.art-4e54cdb1986242f28f188f8252034877 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-23T21:24:41Z |
| publishDate | 2016-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-4e54cdb1986242f28f188f82520348772022-12-21T17:30:38ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242016-05-01166577659310.5194/acp-16-6577-2016Size-resolved morphological properties of the high Arctic summer aerosol during ASCOS-2008E. Hamacher-Barth0C. Leck1K. Jansson2Department of Meteorology, Stockholm University, 10691 Stockholm, SwedenDepartment of Meteorology, Stockholm University, 10691 Stockholm, SwedenDepartment of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, SwedenThe representation of aerosol properties and processes in climate models is fraught with large uncertainties. Especially at high northern latitudes a strong underprediction of aerosol concentrations and nucleation events is observed and can only be constrained by in situ observations based on the analysis of individual aerosol particles. To further reduce the uncertainties surrounding aerosol properties and their potential role as cloud condensation nuclei this study provides observational data resolved over size on morphological and chemical properties of aerosol particles collected in the summer high Arctic, north of 80° N.<br><br> Aerosol particles were imaged with scanning and transmission electron microscopy and further evaluated with digital image analysis. In total, 3909 aerosol particles were imaged and categorized according to morphological similarities into three gross morphological groups: single particles, gel particles, and halo particles. Single particles were observed between 15 and 800 nm in diameter and represent the dominating type of particles (82 %). The majority of particles appeared to be marine gels with a broad Aitken mode peaking at 70 nm and accompanied by a minor fraction of ammonium (bi)sulfate with a maximum at 170 nm in number concentration. Gel particles (11 % of all particles) were observed between 45 and 800 nm with a maximum at 154 nm in diameter. Imaging with transmission electron microscopy allowed further morphological discrimination of gel particles in "aggregate" particles, "aggregate with film" particles, and "mucus-like" particles.<br><br> Halo particles were observed above 75 nm and appeared to be ammonium (bi)sulfate (59 % of halo particles), gel matter (19 %), or decomposed gel matter (22 %), which were internally mixed with sulfuric acid, methane sulfonic acid, or ammonium (bi)sulfate with a maximum at 161 nm in diameter.<br><br> Elemental dispersive X-ray spectroscopy analysis of individual particles revealed a prevalence of the monovalent ions Na<sup>+</sup>/K<sup>+</sup> for single particles and aggregate particles and of the divalent ions Ca<sup>2+</sup>/Mg<sup>2+</sup> for aggregate with film particles and mucus-like particles. According to these results and other model studies, we propose a relationship between the availability of Na<sup>+</sup>/K<sup>+</sup> and Ca<sup>2+</sup>/Mg<sup>2+</sup> and the length of the biopolymer molecules participating in the formation of the three-dimensional gel networks.https://www.atmos-chem-phys.net/16/6577/2016/acp-16-6577-2016.pdf |
| spellingShingle | E. Hamacher-Barth C. Leck K. Jansson Size-resolved morphological properties of the high Arctic summer aerosol during ASCOS-2008 Atmospheric Chemistry and Physics |
| title | Size-resolved morphological properties of the high Arctic summer aerosol during ASCOS-2008 |
| title_full | Size-resolved morphological properties of the high Arctic summer aerosol during ASCOS-2008 |
| title_fullStr | Size-resolved morphological properties of the high Arctic summer aerosol during ASCOS-2008 |
| title_full_unstemmed | Size-resolved morphological properties of the high Arctic summer aerosol during ASCOS-2008 |
| title_short | Size-resolved morphological properties of the high Arctic summer aerosol during ASCOS-2008 |
| title_sort | size resolved morphological properties of the high arctic summer aerosol during ascos 2008 |
| url | https://www.atmos-chem-phys.net/16/6577/2016/acp-16-6577-2016.pdf |
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