Possible transcontinental dust transport from North Africa and the Middle East to East Asia

From the evening of 25 March 2003 until 27 March an Asian dust event (Kosa) was observed at a total of 37 routine meteorological observatories in Japan, although no significant dust storms had been observed in the arid regions of China and Mongolia. A numerical simulation with a three-dimensional global aerosol transport model and meteorological observations reveal that the observed mineral dust particles were generated through dust storms in North Africa and the Middle East on 19 March. The simulation predicted that dust particles generated in the Sahara Desert and Arabian Peninsula on 19 March would be transported north of the Tien Shan Mountains in China and arrive over Japan in about 6–7 days. It also indicated that over 50% of the dust particles in Japan on 26–27 March came from North Africa, about 30% from the Middle East, and only about 10% from China in the boundary layer. The simulated result is consistent with polarization lidar and sky radiometer observations, indicating that the simulation is realistic. The simulation indicates that the Kosa phenomenon was caused by a mixture of transported dust and anthropogenic pollutants. The simulation of this dust event suggests the possible importance of dust transport from the Sahara and the Arabian Peninsula to East Asia.