Applicability of the low-cost OPC-N3 optical particle counter for microphysical measurements of fog
<p>Low-cost devices for particulate matter measurements are characterised by small dimensions and a light weight. This advantage makes them ideal for UAV measurements, where those parameters are crucial. However, they also have some issues. The values of particulate matter from low-cost optica...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-05-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/16/2415/2023/amt-16-2415-2023.pdf |
| Summary: | <p>Low-cost devices for particulate matter measurements are characterised by small dimensions and a light weight. This advantage makes them ideal for UAV measurements, where those parameters are crucial. However, they also have some issues. The values of particulate matter from low-cost optical particle counters can be biased by high ambient humidity. In this article, we evaluate the low-cost Alphasense OPC-N3 optical particle counter for measuring the microphysical properties of fog. This study aimed to show that OPC-N3 not only registers aerosols or humidified aerosols but also registers fog droplets.</p>
<p>The study was carried out on the rooftop of the Institute of Geophysics, University of Warsaw, Poland, during autumn–winter 2021. To validate the results, the data from OPC-N3 were compared with the data obtained from the reference instrument, the Oxford Lasers VisiSize D30. VisiSize D30 is a shadowgraph device able to register photos of individual droplets.</p>
<p>Considering the effective radius of droplets, it is possible to differentiate low-visibility situations between fog conditions (which are not hazardous for people) from haze events, when highly polluted air can cause health risks to people.</p>
<p>The compared microphysical properties were liquid water content (LWC), number concentration (<span class="inline-formula"><i>N</i><sub>c</sub></span>), effective radius <span class="inline-formula"><i>r</i><sub>eff</sub></span> and statistical moments of radius. The Pearson correlation coefficient between both devices for LWC was 0.92, <span class="inline-formula"><i>N</i><sub>c</sub></span> was 0.95 and <span class="inline-formula"><i>r</i><sub>eff</sub></span> was 0.63. Overall, these results suggest good compliance between instruments. However, the OPC-N3 has to be corrected regarding professional equipment.</p> |
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| ISSN: | 1867-1381 1867-8548 |