Experiment on Dust Flux During Duststorm Periods over Desert Area  

作　　者：张宏升 朱好 彭艳 康凌 陈家宜 Soon-Ung PARK 

机构地区：[1]Center of Sino-Korcan Atmospheric Sciences,Department of Atmospheric Sciences,Peking University [2]Center of Sino-Korean Atmospheric Sciences,Department of Atmospheric Sciences,Peking University [3]Center of Sino-Korean Atmospheric Sciences,Department of Atmospheric Sciences,Seoul National University,Seoul 151-742,Korea

出　　处：《Acta meteorologica Sinica》2008年第2期239-247,共9页

基　　金：the National Natural Science Foundation of China under Grant No.40775013;"863" Program of China under Grant No.2006AA06A306;the Special Commonweal Research Program of the Ministry of Science and Technology under Grant No.2008416018;the Research Fund for the Doctoral Program of Higher Education under Grant No.20060001025.

摘　　要：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.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 

分 类 号：P445.4[天文地球—大气科学及气象学]