Importance of dust particles in the free troposphere over the Taklamakan Desert: Electron microscopic experiments of particles collected with a balloonborne particle impactor at Dunhuang, China

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Read Full Article (file size: 508407 bytes) Cited by JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. D23, 8644, doi:10.1029/2002JD003270, 2003 Importance of dust particles in the free troposphere over the Taklamakan Desert: Electron microscopic experiments of particles collected with a balloonborne particle impactor at Dunhuang, China Y. Iwasaka Graduate School of Environmental Studies, Nagoya University, Chikusa-ku, Nagoya, Japan G.-Y. Shi Institute of Atmospheric Physics, Chinese Academy of Science, Beijing, China M. Yamada Graduate School of Environmental Studies, Nagoya University, Chikusa-ku, Nagoya, Japan A. Matsuki Graduate School of Environmental Studies, Nagoya University, Chikusa-ku, Nagoya, Japan D. Trochkine Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan Y. S. Kim Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, Japan D. Zhang Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto, Japan T. Nagatani Graduate School of Environmental Studies, Nagoya University, Chikusa-ku, Nagoya, Japan T. Shibata Graduate School of Environmental Studies, Nagoya University, Chikusa-ku, Nagoya, Japan M. Nagatani Solar-Terrestrial Environment Laboratory, Nagoya University, Toyokawa, Japan H. Nakata Solar-Terrestrial Environment Laboratory, Nagoya University, Toyokawa, Japan Z. Shen Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Science, Lanzhou, China G. Li Institute of Atmospheric Physics, Chinese Academy of Science, Beijing, China B. Chen Institute of Atmospheric Physics, Chinese Academy of Science, Beijing, China Abstract Measurements of aerosol morphology and chemical elements were made in August 2002 at Dunhuang (40°00′N, 94°30′E), China, on the basis of direct sampling of free tropospheric aerosols with a balloonborne particle impactor, to understand nature of atmospheric particles over the desert areas in the Asian continent. Electron microscopic experiments of the particles directly showed that mineral (dust) particles were major constituents of coarse mode particles in the free troposphere over the Taklamakan desert. Typical types of the particles, according to energy dispersive X-ray (EDX) analysis, were Si-rich and Ca-rich particles in heights of about 3–5 km, and the ratio of those particle number to total particle number was about 0.71 in coarse mode range (diameter larger than 1.0 μm). The ammonium sulfate particles were major in fine mode range (diameter smaller than 1.0 μm). This result shows good correspondence with the lidar measurements, which were made in collaboration with this balloonborne measurements. The large depolarization ratio, according to lidar measurements, distributed from near the surface to about 6 km, suggesting that lots of particles having irregular shape (possibly dust particles) were in the free troposphere in summer over the Taklamakan desert. Trajectory analysis of air masses showed the possibility that westerly wind transported those dust particles (Kosa particles) to downwind areas even in summer season above about 5 km, which is interesting and useful information to give explanation on the aircraft measurements made at Japan, showing possible transport of dust particles in the middle and upper troposphere in summer season. Received 1 December 2002; accepted 2 May 2003; published 27 September 2003. Index Terms: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0320 Atmospheric Composition and Structure: Cloud physics and chemistry; 0322 Atmospheric Composition and Structure: Constituent sources and sinks; 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; 0368 Atmospheric Composition and Structure: Troposphere—constituent transport and chemistry. Read Full Article (file size: 508407 bytes) Cited by Citation: Iwasaka, Y., et al. (2003), Importance of dust particles in the free troposphere over the Taklamakan Desert: Electron microscopic experiments of particles collected with a balloonborne particle impactor at Dunhuang, China, J. Geophys. Res., 108(D23), 8644, doi:10.1029/2002JD003270. Copyright 2003 by the American Geophysical Union.

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