Investigation of coastal sea-fog formation using the WIBS (wideband integrated bioaerosol sensor) technique
| Autor: | Stig Hellebust, John C. Wenger, Jovanna Arndt, Patrick Feeney, David A. Healy, Michael Quirke, John R. Sodeau, David O'Connor, Shane M. Daly, Eoin McGillicuddy |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Atmospheric Science
chemical 010504 meteorology & atmospheric sciences 010501 environmental sciences Atmospheric sciences 01 natural sciences Analytical Chemistry Atmosphere Troposphere lcsh:Chemistry Fog Scanning mobility particle sizer Cloud condensation nuclei 0105 earth and related environmental sciences marine Wideband integrated bioaerosol sensor (WIBS-4) Atmospheric aerosols lcsh:QC1-999 Aerosol biological components Chemistry lcsh:QD1-999 Particle Environmental science Cork Harbour Coastal sea-fog lcsh:Physics Bioaerosol |
| Zdroj: | Atmospheric Chemistry and Physics, Vol 19, Pp 5737-5751 (2019) Articles |
| ISSN: | 1680-7324 1680-7316 |
| Popis: | A wideband integrated bioaerosol sensor (WIBS-4) was deployed in Haulbowline Island, Cork Harbour, to detect fluorescence particles in real time during July and September 2011. A scanning mobility particle sizer (SMPS) was also installed providing sizing analysis of the particles over the 10–450 nm range. During the campaign, multiple fog formation events occurred; they coincided with dramatic increases in the recorded fluorescent particle counts. The WIBS sizing and fluorescence intensity profiles indicated that the origin of the signals was potentially non-biological in nature (i.e. PBAPs, primary biological aerosol particles). Furthermore, the data did not support the presence of known fluorescing chemical particles like SOA (secondary organic aerosol). Complementary laboratory studies showed that the field results could potentially be explained by the adsorption of molecular iodine onto water droplets to form I2 ⋅ (H2O)x complexes. The release of iodine into the coastal atmosphere from exposed kelp at low tides has been known for many years. This process leads to the production of small IxOy particles, which can act as cloud condensation nuclei (CCN). While the process of molecular iodine release from coastal kelp sources, subsequent particle formation, and the observations of sea mists and fogs have been studied in detail, this study provides a potential link between the three phenomena. Of mechanistic interest is the fact that molecular iodine included into (rather than on) water droplets does not appear to fluoresce as measured using WIBS instrumentation. The study indicates a previously unsuspected stabilizing transport mechanism for iodine in the marine environment. Hence the stabilization of the molecular form would allow its more extensive distribution throughout the troposphere before eventual photolysis. |
| Databáze: | OpenAIRE |
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