Abstract
Vertical profiles of particulates were measured in Macao by using a 355 nm Mie scattering lidar during a dust event. A high energy pulse laser was employed as the light source to detect the extinction coefficient in the atmosphere. The extinction profiles showed layers of high aerosol concentrations in good agreement with both back trajectory analysis and ground-based pollution measurements in Macao, which indicate that this lidar is very useful for monitoring extinction profiles during extreme high aerosol loading and low visibility atmospheric conditions when most low energy lidar system is inefficient. The results evidenced that correlations between PM2.5 and TSP varied with the intensity of dust storm and the PM2.5/PM10 ratio was small during dust episode, which indicated that aerosols were dominated by large particles. Furthermore, results of the dust event showed high aerosol concentrations at altitudes where the wind carried the dusty aerosols from northern China, covering Shanghai and the Taiwan Channel, to the Pearl River Delta Region. This research improved the understanding of the dust properties in Macao.
Highlights
Macao is a special administrative region (SAR) of China located in the Pearl RiverDelta
The analysis showed that most dust events occurred in spring, summer, and early autumn periods, and the dust layers moved to higher altitudes in spring more than in other seasons
0.6, which indicates a larger contribution of small particles before the dust event
Summary
Macao is a special administrative region (SAR) of China located in the Pearl River. Delta. Satellite remote sensing data and meteorological data were combined with lidar data to study the regional distribution characteristics and transport of pollutants. Fernández et al [56] used lidar and sun-photometer measurements to analyze aerosol optical properties and their evolution in an extreme Saharan dust event. Wang et al [57] used ground-based lidar-photometer method to derive the real-time dust mass extinction efficiency and dust mass concentration profiles They found that the dust mass extinction efficiency was not a fixed value, and the size of dust particles changed in different dust weather processes.
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