Dust transport and advection measurement with spaceborne lidars ALADIN and CALIOP and model reanalysis data

• Published in: Atmospheric chemistry and physics 2022-06, Vol.22 (12), p.7975-7993
• Main Authors: Dai, Guangyao, Sun, Kangwen, Wang, Xiaoye, Wu, Songhua, E, Xiangying, Liu, Qi, Liu, Bingyi
• Format: Article
• Language: English
• Subjects: Advection; Aerosols; Air pollution; Analysis; Atmospheric lasers; Atmospheric particulates; Deposition; Doppler sonar; Dust; Dust plumes; Dust storms; Dust transport; Ecosystems; Emissions; Experiments; Geochemistry; Lasers; Lidar; Measurement; Oceans; Optical properties; Optical radar; Orbits; Plumes; Pollution monitoring; Radiation; Relative humidity; Remote sensing; Saharan dust; Saharan dust transport; Synchronism; Synchronization; Tracking; Trajectory analysis; Transport processes; Wind; Wind fields
• ISSN: 1680-7324; 1680-7316; 1680-7324
• DOI: 10.5194/acp-22-7975-2022

In this paper, a long-term large-scale Saharan dust transport event which occurred between 14 and 27 June 2020 is tracked with the spaceborne lidars ALADIN (Atmospheric Laser Doppler Instrument) and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) together with ECMWF (European Centre for Medium-Range Forecasts) and HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory model) analysis. We evaluate the performance of ALADIN and CALIOP on the observations of dust optical properties and wind fields and explore the possibility of tracking the dust events and calculating the dust mass advection with the combination of satellite and model data. The dust plumes are identified with the AIRS/Aqua Dust Score Index and with the vertical feature mask product from CALIOP. The emission, dispersion, transport and deposition of the dust event are monitored using the data from AIRS/Aqua, CALIOP and HYSPLIT. With the quasi-synchronized observations by ALADIN and CALIOP, combined with the wind field and relative humidity, the dust advection values are calculated. From this study, it is found that the dust event generated on 14 and 15 June 2020 from the Sahara in North Africa dispersed and moved westward over the Atlantic Ocean, finally being deposited in the western Atlantic Ocean, the Americas and the Caribbean Sea. During the transport and deposition processes, the dust plumes are trapped in the northeasterly trade-wind zone between latitudes of 5∘ and 30∘ N and altitudes of 0 and 6 km. Aeolus provided the observations of the dynamics of this dust transport event in the Saharan Air Layer (SAL). From the measurement results on 19 June 2020, the dust plumes are captured quasi-simultaneously over the emission region (Western Sahara), the transport region (middle Atlantic) and the deposition region (western Atlantic) individually, which indicates that the dust plume area over the Atlantic on the morning of this day is quite enormous and that this dust transport event is massive and extensive. The quasi-synchronization observation results of 15, 16, 19, 24 and 27 June by ALADIN and CALIOP during the entire transport process show good agreement with the Dust Score Index data and the HYSPLIT trajectories, which indicates that the transport process of the same dust event is tracked by ALADIN and CALIOP, verifies that the dust transport spent around 2 weeks from the emission to the deposition and achieved the respective observations of this dust event's emission