Surface measurements of aerosol properties over northwest China during ARM China 2008 deployment

[1] To improve understanding and capture the direct evidence of the impact of dust aerosol on climate, the 2008 China-U.S. joint field campaigns are conducted. Three sites are involved this campaign, including one permanent site (Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL)) (located in Yuzhong, 35.95 degrees N, 104.1 degrees E), one SACOL's Mobile Facility (SMF) (deployed in Jintai, 37.57 degrees N, 104.23 degrees E), and the U. S. Department of Energy Atmospheric Radiation Measurements (ARM) Ancillary Facility (AAF mobile laboratories, SMART-COMMIT) (deployed in Zhangye, 39.08 degrees N, 100.27 degrees E). This paper presents the results of direct measurement analysis of the dust plume transport case. During the dust plume period, the OMI AI data and air mass back trajectory model (HYSPLIT) clearly illustrated that the air mass originated from the Taklamakan desert and Inner Mongolia Gobi desert. The daily averaged concentrations of PM10 were about 0.2 +/- 0.03 mg/m(3) at SACOL and Zhangye, but during the dust plume the mass concentration of dust aerosol were 0.98 mg/m(3) at Zhangye and 0.52 mg/m(3) at SACOL. The black carbon (BC) value reached its high peak during the dust plume. However, the concentration of BC was not only fluctuated with the dust plume, but also affected by the local air pollutants. When the dust plume occurred, the multiwavelength aerosol optical depth can be raised to similar to 2, similar to 1.5 times as high as that during the non dust plume period, and the number (mass) distribution during the dust plume showed the aerosol types considered correspond to urban/industrial aerosols, coarse mode particles. The meteorological analysis indicated that these polluted layers are not only transported from their sources, but also include the local sources.