TEMPORAL AND SPATIAL DISTRIBUTIONS OF DUST AND ITS DEPOSITION TO THE CHINA SEA

Atmospheric concentrations of aluminum, an indicator of dust substance s, have been determined in a set of high-volume aerosol particle sampl es collected at different locations over continental China and over th e China Sea. High concentrations of dust were observed in northern con tinental China, and at certain locations such as Beijing dust may incl ude an anthropogenic fraction. The mass particle-size distributions of dust varied depending on its distance from source regions, with the m ass median diameter for Al of similar to 1.6-5.9 mu m at Beijing in no rthern China and similar to 1.9 mu m over off-shore areas of the East China Sea. Model-predicted mean dry deposition velocities of dust part icles are from 1.4 to 4.8 cm s(-1) over northern continental China and from 1.4 to 2.1 cm s(-1) over the China Sea. Atmospheric deposition m odels have been applied to estimate the atmospheric fluxes and deposit ion of dust at different locations. The estimated atmospheric flux of dust at Xi'an of the Loess Plateau is 25 (4.9 to 44) g m(-2) mo(-1) wh ich is the highest among the regions we studied. The estimated present -day dust flux is comparable to the late quaternary records of eolian dust accumulation at this site. The total atmospheric deposition of du st to the China Sea is 67 Tg yr(-1), accounting for 14% of the total a tmospheric deposition of dust to the entire North Pacific. With such a high deposition rate, Asian dust may play an important role in biogeo chemical cycles of trace substances in the Asia/North Pacific region.