Unmanned Aerial Vehicle Observations of the Vertical Distribution of Particulate Matter in the Surface Layer of the Taklimakan Desert in China

Abstract

Field observations made with unmanned aerial vehicles of the particulate matter (PM) concentration from the ground to a height of 500 m were conducted at Xiaotang and Tazhong in the Taklimakan Desert (TD), China, from 7 to 15 November 2019. The vertical structures of the PM concentrations were studied. Pulsed lidar observations showed that dust aerosols in the TD can reach heights of 4 km. Within 500 m above the ground, the PM1.0, PM2.5, and PM10 concentrations were <100, <201, and <764 µg∙m−3, respectively, in the TD. On days containing sand-blowing periods (e.g., at 18:00 on 11 November), the PM1.0, PM2.5, and PM10 concentrations were 10–17.7 times higher than on clear days. The northern margin of the TD (Xiaotang) was dominated by fine particles, while the hinterland (Tazhong) was dominated by coarse particles, because there was sparse vegetation around Xiaotang and the surface was sand and clay, while there was no vegetation around Tazhong and the surface was sand. During floating dust periods, the boundary layer was dominated by fine particles. The average PM1.0/PM2.5 ratios were 0.25–0.65 and 0.40–0.80 at Tazhong and Xiaotang, respectively, while, during sand blowing periods, these ratios were 0.40–0.55 and 0.40–0.45, respectively. The critical condition in the atmospheric boundary layer for PM concentration was revealed with the enhanced momentum flux and sensible heat flux up to 0.52 kg∙m−1∙s−2, 0.69 m∙s−1, and 6.7 W∙m2, respectively, and the low mixed layer was high in the lower atmosphere.

Construction of liquid metal-based soft microfluidic sensors via soft lithography

“…Based on the high thermal conductivity and electrical conductivity of LM-based microfluidic electronics [ 35 ], we explored a sensing concept of thermal-dynamic conversion. Due to the soft and stretching performance of the LM microfluidic circuits, the geometrical shape of LM will change along the deformation of the elastomers, as a result, the resistance of LM circuits changes accordingly.…”

Peer Review #2 of "Characteristics of solar radiation at Xiaotang, in the northern marginal zone of the Taklimakan Desert (v0.1)"

“…Huang et al (2010) attempted to improve the accuracy of the simulation analysis of clear-sky surface shortwave radiation using the CERES SSF dataset, and aerosol optical depth (AOD) plays a crucial role in deciding the accuracy of simulation analysis. Jin et al (2011) conducted UAV experiments and found that particles size, concentrations, and daily variations in the concentration of PM were different in the Xiaotang and Tazhong Station. On clean days, the mean concentrations of PM 1.0 , PM 2.5 , and PM 10 were 3.6, 6.9, and 18.9 µg•m −3 in the Xiaotang area and 6.5, 13.2, and 26.8µg•m −3 in the Tazhong area, respectively.…”

Characteristics of solar radiation at Xiaotang, in the northern marginal zone of the Taklimakan Desert

“… Huang et al (2020) attempted to improve the accuracy of the simulation analysis of clear-sky surface shortwave radiation using the CERES SSF dataset, and aerosol optical depth (AOD) plays a crucial role in deciding the accuracy of simulation analysis. Jin et al (2011) conducted UAV experiments and found that particles size, concentrations, and daily variations in the concentration of PM were different in the Xiaotang and Tazhong Station. On clean days, the mean concentrations of PM 1.0 , PM 2.5 , and PM 10 were 3.6, 6.9, and 18.9 µg m −3 in the Xiaotang area and 6.5, 13.2, and 26.8 µg mg m −3 in the Tazhong area, respectively.…”