Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 15, 11067-11080, 2015
https://doi.org/10.5194/acp-15-11067-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
06 Oct 2015
Optical properties of long-range transported Saharan dust over Barbados as measured by dual-wavelength depolarization Raman lidar measurements
S. Groß1, V. Freudenthaler2, K. Schepanski4, C. Toledano3, A. Schäfler1, A. Ansmann4, and B. Weinzierl1,2 1Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
2Ludwig-Maximilians-Universität, Meteorologisches Institut, München, Germany
3Universitat de Valladolid, Valladolid, Spain
4Leibniz-Institut für Troposphärenforschung (TROPOS), Leipzig, Germany
Abstract. Dual-wavelength Raman and depolarization lidar observations were performed during the Saharan Aerosol Long-range Transport and Aerosol-Cloud interaction Experiment in Barbados in June and July 2013 to characterize the optical properties and vertical distribution of long-range transported Saharan dust after transport across the Atlantic Ocean. Four major dust events were studied during the measurements from 15 June to 13 July 2013 with aerosol optical depths at 532 nm of up to 0.6. The vertical aerosol distribution was characterized by a three-layer structure consisting of the boundary layer, the entrainment or mixing layer and the pure Saharan dust layer. The upper boundary of the pure dust layer reached up to 4.5 km in height. The contribution of the pure dust layer was about half of the total aerosol optical depth at 532 nm. The total dust contribution was about 50–70 % of the total aerosol optical depth at 532 nm. The lidar ratio within the pure dust layer was found to be wavelength independent with mean values of 53 ± 5 sr at 355 nm and 56 ± 7 sr at 532 nm. For the particle linear depolarization ratio, wavelength-independent mean values of 0.26 ± 0.03 at 355 nm and 0.27 ± 0.01 at 532 nm have been found.

Citation: Groß, S., Freudenthaler, V., Schepanski, K., Toledano, C., Schäfler, A., Ansmann, A., and Weinzierl, B.: Optical properties of long-range transported Saharan dust over Barbados as measured by dual-wavelength depolarization Raman lidar measurements, Atmos. Chem. Phys., 15, 11067-11080, https://doi.org/10.5194/acp-15-11067-2015, 2015.
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Short summary
In June and July 2013 dual-wavelength lidar measurements were performed in Barbados to study long-range transported Saharan dust across the Atlantic Ocean and investigate transport-induced changes. The focus of our measurements is the intensive optical properties, the lidar ratio and the particle linear depolarization ratio. While the lidar ratio shows no differences compared to the values of fresh Saharan dust, the particle linear depolarization ratio shows slight differences.
In June and July 2013 dual-wavelength lidar measurements were performed in Barbados to study...
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