2018 Volume 53 Issue 5 Pages 165-185
Various desert and semi-arid areas in Northeast Asia that are susceptible to sandstorms and the generation of kosa aerosols have been investigated over a ten-year period commencing in 1998. Sixty-four samples of surface soils were collected from eight regions in the Taklamakan, Gobi deserts, the Hung tu (Chinese Loess) Plateau, and others. The grainy soil particulates (<100 μm) and the fine soil particulates (<10 μm) were classified by the sieve/cascade-impactor methods, and the chemical compositions of the particulates were determined. The darkest yellow-red colored samples were a group of surface soil samples from the Eastern Gobi region, and it was found that the CO3-C, Ca and Mg contents were significantly less than those from the other areas. It was postulated that there was an underdeveloped formation/accumulation process of calcite mineralization in the surface soil layer of the Eastern Gobi. The concentration ratios of Ca, Mg, Sr and P to Al exhibited relatively large variations (15–52 RSD%), whereas the ratios, with respect to Al, for K, Ti, and Ba were significantly lower (7–9 RSD%). A cluster analysis based on the elemental ratios (with respect to Al) for Ca, Mg, Sr and P was used to identify the sources of the kosa aerosols which were transported to Japan (16 events studied). The estimated source regions of the kosa aerosols were substantiated using observational regions based on the SYNOP network reports about dust storms.
