While only 15 % of the total emitted dust load is transported north- and eastwards towards the Mediterranean and the Middle East (e.g., Shao et al., 2011), almost 85 % of the dust burden gets carried south- and westwards over the Atlantic Ocean. Once injected into the atmosphere, Saharan dust particles can be transported far away from their origin. This makes up roughly 50 % of the total global annual dust emission (1000–4000 Tg a −1). ( 2011) derived annual dust emissions from North Africa that range from 400 to 2200 Tg a −1. The greatest source region of mineral dust is the Sahara and its arid surrounding landscapes.įrom a comparison of 15 global aerosol models, Huneeus et al. Mineral dust aerosol is known to be a major contributor to the earth's aerosol mass burden ( Cakmur et al., 2006) and is estimated to contribute between 25 % and 30 % to the total aerosol optical depth ( Tegen et al., 1997 Kinne et al., 2006). Such enhancements have already been observed during summertime and were found to have a great impact on radiative transfer and atmospheric stability.
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No pure mineral dust regimes were observed.Īdditionally, all the dust-laden air masses that were observed during EUREC 4A came along with enhanced water vapor concentrations compared with the free atmosphere above. Only mixtures of dust particles with other aerosol species, i.e., biomass-burning aerosol from fires in West Africa and marine aerosol, were detected by the lidar.
In contrast to summertime dust transport, mineral dust aerosols were transported at lower altitudes and were always located below 3.5 km.Ĭalculated backward trajectories affirm that the dust-laden layers have been transported in nearly constant low-level altitude over the North Atlantic Ocean.
The combination of the water vapor differential absorption and high spectral resolution lidar techniques together with dropsonde measurements aboard the German HALO (High Altitude and Long-Range) research aircraft enable a detailed vertical and horizontal characterization of the measured dust plumes. The measurements were conducted in the framework of the EUREC 4A (Elucidating the Role of Cloud-Circulation Coupling in Climate) field experiment upstream the Caribbean island in January–February 2020. Wintertime Saharan dust plumes in the vicinity of Barbados are investigated by means of airborne lidar measurements.
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