A Study on Microphysical Characteristics of Fog Particles at CPOS in Pyeongchang Region

The data used in the present study were obtained from Cloud Physics Observation Site (CPOS), which has been operating by the National Institute of Meteorological Sciences (NIMS) since July 2006 at Daegwallyeong in Pyeongchang of South Korea. CPOS has 17 instruments observing meteorological conditions and microphysical characteristics of aerosol, cloud, and precipitation. Especially the Particle Measuring System (PMS) covers all size range of hydrometeor particles. The purpose of this study is to investigate the characteristics of fog size distributions using long-term accumulated data (about 12 years) of ground-based Fog Monitor (FM-120, range: 2-50 ㎛), Meteorological Particle Spectrometer (MPS, range: 50-3100 ㎛), Visibility Sensor (VS), and PARSIVEL disdrometer. We analyzed the fog particle size distributions during the four season period (2013-2016). The fog size distributions with and without precipitation are quite different for two events. In the overlapped range near 50 ㎛, the measured concentration of particles by FM-120 and MPS shows somewhat difference. The difference has been decreased by excluding the precipitation cases (> 0 mm/h), which indicates that these instruments should consider the pure floating particles without raindrops. These consistent data gives the seasonal behavior (the highest number concentration of fog particles in summer season) of fog particle size distribution in the Pyeongchang region.