Profiling Dust Mass Concentration in Northwest China Using a Joint Lidar and Sun-Photometer Setting

Self Cite

Previous studies have shown that dust aerosols may accelerate the melting of snow and glaciers over the Tibetan Plateau. To investigate the vertical structure of dust aerosols, we conducted a ground-based observation by using multi-wavelength polarization lidar which is designed for continuous network measurements. In this study, we used the lidar observation from September to October 2020 at the Ruoqiang site (39.0°N, 88.2°E; 894 m ASL), located at the junction of the Taklimakan Desert–Tibetan Plateau. Our results showed that dust aerosols can be lifted up to 5 km from the ground, which is comparable with the elevation of the Tibetan Plateau in autumn with a mass concentration of 400–900 μg m−3. Moreover, the particle depolarization ratio (PDR) of the lifted dust aerosols at 532 nm and 355 nm are 0.34 ± 0.03 and 0.25 ± 0.04, respectively, indicating the high degree of non-sphericity in shape. In addition, extinction-related Ångström exponents are very small (0.11 ± 0.24), implying the large values in size. Based on ground-based lidar observation, this study proved that coarse non-spherical Taklimakan dust with high concentration can be transported to the Tibetan Plateau, suggesting its possible impacts on the regional climate and ecosystem.

Section: Dust Case 1: 13 September 2020mentioning

confidence: 98%

Polarization Lidar Measurements of Dust Optical Properties at the Junction of the Taklimakan Desert–Tibetan Plateau

Dong

Huang

et al. 2022

Self Cite

“…It should be noticed that the assumed aerosol density needs to be adjusted carefully, according to the empirical values that Ma et al (2020) reported [39]. According to the statistical analysis of many researches, the assumed aerosol density of 1.6 g/cm 3 is appropriate and acceptable for most atmospheric conditions [9,36,38,40], while it needs to be adjusted to 2.6 g/cm 3 when the dominating aerosol types are dust/polluted dust [41][42][43] and should be set in the range of 0.8 g/cm 3 to 1.1 g/cm 3 when the dominating aerosol type is pollen aerosol [44]. Finally, the vertical turbulent aerosol mass fluxes could be retrieved with similar technique introduced before [9].…”

Section: Vertical Aerosol Mass Fluxes Retrieval By a CDL And A Sun Ph...mentioning

confidence: 99%

Retrieval and Calculation of Vertical Aerosol Mass Fluxes by a Coherent Doppler Lidar and a Sun Photometer

Dai

Sun

et al. 2021

The direct and indirect radiation forcing of aerosol particles deeply affect the energy budget and the atmospheric chemical and physical processes. To retrieve the vertical aerosol mass fluxes and to investigate the vertical transport process of aerosol by a coherent Doppler lidar (CDL), a practical method for instrumental calibration and aerosol optical properties retrieval based on CDL and sun photometer synchronization observations has been developed. A conversion of aerosol optical properties to aerosol microphysical properties is achieved by applying a well-developed algorithm. Furthermore, combining the vertical velocity measured simultaneously with a CDL, we use the eddy covariance (EC) method to retrieve the vertical turbulent aerosol mass fluxes by a CDL and sun photometer with a spatial resolution of 15 m and a temporal resolution of 1 s throughout the planetary boundary layer (PBL). In this paper, we present a measurement case of 24-h continuous fluxes observations and analyze the diurnal variation of the vertical velocity, the aerosol backscatter coefficient at 1550 nm, the mean aerosol mass concentration, and the vertical aerosol mass fluxes on 13 April 2020. Finally, the main relative errors in aerosol mass flux retrieval, including sample error σF,S, aerosol optical properties retrieval error σF,R, and error introduced from aerosol microphysical properties retrieval algorithm σF,I, are evaluated. The sample error σF,S is the dominating error which increases with height except during 12:00–13:12 LST. The aerosol optical properties retrieval error σF,R is 21% and the error introduced from the aerosol microphysical properties retrieval algorithm σF,I is less than 50%.

“…When dust weather occurs, it not only impacts the ambient air quality [1][2][3] but also poses a threat to human health [4][5][6][7]. Furthermore, mineral dust aerosol can influence changes in the radiation energy budget [8,9] and atmospheric thermal structures [10], and it can be transported to the Tibetan Plateau (TP) or polar regions [11][12][13]. This transportation process has the potential to cause significant melting of snow and ice [14].…”

Section: Introductionmentioning

confidence: 99%

Summer Extreme Dust Activity in the Taklimakan Desert Regulated by the South Asian High

Wang

Han

et al. 2023

Self Cite

Summer dust aerosol in the Taklimakan Desert (TD) affects not only the albedo of the snow and ice sheets on the Tibetan Plateau (TP) but also air quality and precipitation in the downstream areas. In this study, the summer extreme dust activity in the TD was jointly investigated by using satellite observations and MERRA-2 reanalysis datasets and divided into two states: dust active period and dust inactive period. The horizontal and vertical distribution of summer dust during both the dust active and inactive periods, as derived from the MERRA-2 dataset, is consistent with satellite observations. By comparing the upper-level circulation and surface meteorological elements at two periods, we identify the South Asian High (SAH) as the dominant factor driving the extreme dust activity in the TD during summer. When the SAH is centered on the Iranian Plateau (IP), the dust aerosol in the TD exhibits increased activity and is lifted to higher altitudes due to significantly enhanced westerly winds, near-surface wind speed, and an ascending motion. Conversely, when the SAH is centered on the TP, the summer dust activity shows the opposite behavior. These new findings on the regulatory mechanism of the SAH on the summer dust activity in the TD are highly significant for understanding the occurrence and transport of summer Asian dust and its potential impact on heavy precipitation in the downstream areas.