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Experiment on dust flux During duststorm Periods over Desert Area

Acta meteorologica Sinica 2008年第2期22卷 239-247页

作者：张宏升朱好彭艳康凌陈家宜 Soon-Ung PARK Center of Sino-Korcan Atmospheric Sciences Department of Atmospheric SciencesPeking University Center of Sino-Korean Atmospheric Sciences Department of Atmospheric SciencesPeking University Center of Sino-Korean Atmospheric Sciences Department of Atmospheric SciencesSeoul National UniversitySeoul 151-742Korea

The present study investigates the characteristics of turbulent transfer and the conditions for dust emission and transport using the dust concentration and micrometeorological data obtained during dust events occurring in the spring of 2004 over the Hunshandake desert area. The turbulent exchange coefficients and turbulent fluxes of momentum and heat are calculated. The relationships between dust flux, friction velocity, and wind speed are also explored. The results show that thermal turbulence is dominant during daytime of non-dusty days. The dynamic turbulence increases obviously and the sensible heat flux reduces by different degrees during dust events. There is an efficient downward transfer of momentum before duststorm occurrence, and both the dynamic turbulence and the thermal turbulence are important in the surface layer. The dynamic turbulence even exceeds the thermal turbulence during severe duststorm events. The values of dust flux vary in the range of -5 5, -30 30, and -200-300 μg m^-2 s^-1 during non-dusty days, blowing dust, and duststorm events, respectively. A slight upward transport of dust is observed during non-dusty days. The dust flux gradually varies from positive to negative during duststorm periods, which indicates the time evolution of dust events from dust rising to stably suspending and then deposition. The dust flux is found to be proportional to u＊^3. The threshold values of wind speed and friction velocity are about 6 and 0.4 m s^-1, respectively.

关键词： turbulent transfer dust flux threshold friction velocity dust event Hunshandake desert area

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Atmospheric particulate pollution of Lanzhou using magnetic measurements

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Journal of Environmental Sciences 1999年第3期11卷 373-377页

To differentiate between natural and anthropogenic particulate sources in the atmosphere in Lanzhou City, samples were collected in different sites. The dust flux was calculated and magnetic measurements were conducted. Results show a distinct pattern of variation of dust flux within a year and it agrees with the shifts of atmospheric circulation regime. The magnetic parameters indicate that natural sources are the major components of atmospheric particulate during late spring and early summer, while anthropogenic sources contribute much more during winter months. The data also support the earlier findings that magnetic parameters are effective for differentiating between particulate arising from natural sources such as soil erosion and from anthropogenic sources such as coal combustion.

关键词： atmospheric particulate dust flux magnetic measurement Lanzhou of China.

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