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Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.Gultepe, Ismail Cloud Physics and Severe Weather Research Section, Environment Canada. Number of Authors: 2 2016 (English)In: Pure and Applied Geophysics, ISSN 0033-4553, E-ISSN 1420-9136, Vol. 173, no 9, 3049-3064 p.Article in journal (Refereed) Published

Abstract [en] : Ice fog, diamond dust, and light snow usually form over extremely cold weather conditions, and they affect both visibility and Earth’s radiative energy budget. Prediction of these hydrometeors using models is difficult because of limited knowledge of the microphysical properties at the small size ranges due to measurement issues. These phenomena need to be better represented in forecast and climate models; therefore, in addition to remote sensing accurate measurements using ground-based instrumentation are required. An imaging instrument, aimed at measuring ice fog and light snow particles, has been built and is presented here. The ice crystal imaging (ICI) probe samples ice particles into a vertical, tapered inlet with an inlet flow rate of 11 L min−1. A laser beam across the vertical air flow containing the ice crystals allows for their detection by a photodetector collecting the scattered light. Detected particles are then imaged with high optical resolution. An illuminating LED flash and image capturing are triggered by the photodetector. In this work, ICI measurements collected during the fog remote sensing and modeling (FRAM) project, which took place during Winter of 2010–2011 in Yellowknife, NWT, Canada, are summarized and challenges related to measuring small ice particles are described. The majority of ice particles during the 2-month-long campaign had sizes between 300 and 800 μm. During ice fog events the size distribution measured had a lower mode diameter of 300 μm compared to the overall campaign average with mode at 500 μm.

Place, publisher, year, edition, pages: 2016. Vol. 173, no 9, 3049-3064 p.

Keyword [en] : Ice fog, snow, precipitation, ice particles, fall speed, optical imaging, Earth sciences - Atmosphere and hydrosphere sciences

Keyword [sv] : Geovetenskap - Atmosfärs- och hydrosfärsvetenskap

National Category : Aerospace Engineering

Research subject: Atmospheric science

Identifiers: URN: urn:nbn:se:ltu:diva-2909DOI: 10.1007/s00024-016-1343-7ISI: 000382941400005Scopus ID: 2-s2.0-84986620977Local ID: 0a4144d5-c9bd-4686-8bab-f783b6fceab3OAI: oai:DiVA.org:ltu-2909DiVA: diva2:975763

Note: Validerad; 2016; Nivå 2; 2016-10-12 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2016-10-19Bibliographically approved



Author: Kuhn, Thomas

Source: http://ltu.diva-portal.org/







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