Characteristics of Aerosol Number Concentrations over the Ice-Covered Okhotsk Sea

抄録

Aerosol number concentrations were observed in conjunction with in-situ meteorological parameters aboard the patrol vessel SOYA in February 2003 over the ice-covered Okhotsk Sea. The concentrations of particles with radii larger than 0.35 μm were close to the background level, while concentrations of particles less than 0.35 μm were close to the remote continental level. During the observation period, relatively higher and lower aerosol number concentrations (HA and LA) were observed, depending on synoptic weather conditions. Backward trajectory analyses revealed that for the HA period, the air mass in the study region traced back to the Sea of Japan; for the LA period, the air mass originated from the northern ice-covered area. This suggests that sea ice influences the aerosol number concentration by suppressing the amount of oceanic sea salt supplied to air masses. Using the observational data and an empirical formula, differences in surface solar radiation between the HA and LA periods were alsoexamined.