Online ISSN : 1349-6476
ISSN-L : 1349-6476
An Unreported Asian Dust (Kosa) Event in Hokkaido, Japan: A Case Study of 7 March 2016
Teppei J. YasunariMasashi NiwanoYasushi FujiyoshiAtsushi ShimizuMasamitsu HayasakiTeruo AokiArlindo M. da SilvaBrent N. HolbenSumito MatobaNaoto MuraoSadamu YamagataKyu-Myong Kim
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Supplementary material

2017 Volume 13 Pages 96-101


Monitoring particulate matter is essential to alert the public about health risks. The Terra/MODIS true color image clearly captured a yellow band over Hokkaido prefecture in Japan on 7 March 2016. We investigated whether this event was an Asian dust (Kosa) transport or not with the ground-based observations in Sapporo and Takikawa in Hokkaido and NASA's MERRA-2 re-analysis data. The timing of increased particle number concentrations (PNCs; greater than 0.5 μm) was clearly measured by a low-cost aerosol sensor at Sapporo and Takikawa in the early afternoon. For this particle size range, the PNC by this aerosol sensor had greater agreement with another commercial instrument for the 1-hourly mean data. The lidar data at Takikawa and NASA's AERONET at Sapporo also implied the increased dust particles (i.e., dominance of non-spherical and coarse particles, respectively), which supported that the PNC increase was due to the dust transport. The hourly PM2.5 data in Sapporo significantly increased in the evening rather than around the noon to early afternoon. We concluded that this event was judged as an Asian dust (Kosa) event in Hokkaido starting from the early afternoon, which was, however, not reported by Japan Meteorological Agency (JMA) based on their visible observations.

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© 2017 by the Meteorological Society of Japan
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