摘要
Measurements were performed in spring 2001 and 2002 to determine the characteristics of soil dust in the Chinese desert region of Dunhuang, one of the ground sites of the Asia-Pacific Regional Aerosol Characterization Experiment （ACE-Asia）. The mean mass concentrations of total suspended particle matter during the spring of 2001 and 2002 were 317μg m^-3 and 307μg m^-3, respectively. Eleven dust storm events were observed with a mean aerosol concentration of 1095μg m^-3, while the non-dusty days with calm or weak wind speed had a background aerosol loading of 196μg m^-3 on average in the springtime. The main minerals detected in the aerosol samples by X-ray diffraction were illite, kaolinite, chlorite, quartz, feldspar, calcite and dolomite. Gypsum, halite and amphibole were also detected in a few samples. The mineralogical data also show that Asian dust is characterized by a kaolinite to chlorite （K/C） ratio lower than 1 whereas Saharan dust exhibits a K/C ratio larger than 2. Air mass back-trajectory analysis show that three families of pathways are associated with the aerosol particle transport to Dunhuang, but these have similar K/C ratios, which further demonstrates that the mineralogical characteristics of Asian dust are different from African dust.
Measurements were performed in spring 2001 and 2002 to determine the characteristics of soil dust in the Chinese desert region of Dunhuang, one of the ground sites of the Asia-Pacific Regional Aerosol Characterization Experiment （ACE-Asia）. The mean mass concentrations of total suspended particle matter during the spring of 2001 and 2002 were 317μg m^-3 and 307μg m^-3, respectively. Eleven dust storm events were observed with a mean aerosol concentration of 1095μg m^-3, while the non-dusty days with calm or weak wind speed had a background aerosol loading of 196μg m^-3 on average in the springtime. The main minerals detected in the aerosol samples by X-ray diffraction were illite, kaolinite, chlorite, quartz, feldspar, calcite and dolomite. Gypsum, halite and amphibole were also detected in a few samples. The mineralogical data also show that Asian dust is characterized by a kaolinite to chlorite （K/C） ratio lower than 1 whereas Saharan dust exhibits a K/C ratio larger than 2. Air mass back-trajectory analysis show that three families of pathways are associated with the aerosol particle transport to Dunhuang, but these have similar K/C ratios, which further demonstrates that the mineralogical characteristics of Asian dust are different from African dust.
基金
The authors are very grateful to the anonymous reviewers for their constructive suggestions and comments.This research was supported by the National Natural Science Foundation of China(Grant No.40405023)
the Chinese National Key Project of Basic Research(Grant G2004CB720200)
the Science Foundation of Xi'an Jiaotong University(Grant No.XJJ2004006)
a grant from the State Key Laboratory of Loess and Quaternary Geology(SKLLQG),Chinese Academy of Sciences.
