FORMATION OF ASIAN DUST-STORM PARTICLES MIXED INTERNALLY WITH SEA-SALT IN THE ATMOSPHERE

In the spring of 1991, individual aerosol particles were collected on electron microscopic grids in Beijing (China) and Nagasaki (Japan). In order to study the change in the chemical composition of Asian dust-s torm particles during transport, the dust particles were examined usin g an electron microscope equipped with an energy-dispersive X-ray (EDX ) analyzer. An isentropic backward-trajectory analysis was carried out in order to obtain the transport path of the dust-storm particles. Sp atial distributions of clouds by the Geostationary Meteorological Sate llite (GMS) were also used in order to examine the presence of clouds along the transport path. Asian dust-storm particles mixed internally with sea salt (mixed particles) ranged from 16 to 100 % among the dust particles in the air over Nagasaki. For the two cases that the same d ust-storm events were observed in Beijing and Nagasaki, dust-storm par ticles containing sea salt were present abundantly in Nagasaki in a ca se that the air would have been influenced largely by clouds in the ma ritime atmosphere during the transport. It is suggested that these mix ed dust-storm particles were formed by cloud processes.