Dust, biomass burning smoke, and anthropogenic aerosol detected by polarization-sensitive Mie lidar measurements in Mongolia

Polarization-sensitive Mie-scattering lidars were installed for dust storm monitoring at Sainshand and Zamyn-Uud in the Gobi Desert and at the Mongolian capital city of Ulaanbaatar in 2007. We studied the temporal and spatial distributions and transportation of dust, elevated dust, biomass burning smoke, and anthropogenic aerosol by using lidar measurements from the end of 2007 to the first half of 2010. The study results show that the maximum height of dust layers over the Gobi Desert of Mongolia during dust event periods varied from 0.5 to 5.5 km above the ground level (AGL). The 95th percentile level of dust vertical distribution was found at 4 and 4.5 km for Zamyn-Uud and Sainshand, respectively. The averaged maximum height of dust layers during dust events was 2.0–2.2 km AGL at those Gobi sites. The lidar measurements also revealed transport of dust layers elevated in the atmosphere. Base heights of elevated dust layers varied from 0.5 to 2.5 km AGL, while maximum heights from 2.5 to 4.5 km AGL. Backward air trajectory analyses suggested source areas of the elevated dust that transported from other source regions to southeastern Mongolia. A detail study was conducted of the dust event in 19–20 May 2008. Hourly maximum dust concentrations of PM10 (PM2.5) reached 1139–1409 (384–404) μg m−3 during the dust event episode. Dust concentration of PM10 had high correlations with visibilities. Threshold winds for dust emission were determined at Sainshand and Zamyn-Uud. The lidar measurements at the three sites detected vertical profiles of biomass burning smoke and anthropogenic aerosol with top heights of 3–4 km AGL.

► Top heights of dust vertical profiles were 0.5–5.5 km over the Gobi by lidars.
► Elevated dust layers had base heights of 0.5–2.5 km and top heights of 2.5–4.5 km.
► Averaged heights of dust layers were 2.0–2.2 km at the two Gobi sites.
► Transported air pollution and biomass burning smoke were extending up to 3–4 km.
► Threshold winds for dust emission were determined for the two Gobi sites.