Beschreibung:
<jats:p>Abstract. Soil erosion aerosols can be transported considerable distances, the Sahara
being one of the major sources in the world. In June 2016 the volume
scattering function of the atmospheric aerosol was determined in the Sierra
Nevada, Spain, at an altitude of 2500 m. Measurements were performed with a
polar nephelometer permitting measurements between scattering angles of 5 to
175∘. The values at the missing angles could be estimated to a high
accuracy, using the shape of the scattering function adjacent to the missing
angles, and thus a complete volume scattering function was available. During
the measuring period intrusions of long-range transported Sahara aerosol
happened several times. The classification of the aerosol was done by back
trajectories and by the Angström exponent of the wavelength-dependent
scattering coefficient, which was determined by a three-wavelength
Integrating Nephelometer. The phase function of the Sahara aerosol had a
stronger forward scattering, and less backscattering compared to the
non-Sahara aerosol, which is in agreement with other findings for irregular
particles. The asymmetry parameter of the phase function is the best
characteristic to distinguish Sahara aerosol from non-Sahara aerosol. In this
study the asymmetry parameter for the Sahara aerosol was larger than 0.65,
whereas the non-Sahara aerosol had an asymmetry parameter below 0.6. A
comparison with measurements performed with long-range transported Gobi
desert aerosols observed in Kyoto, Japan, showed very similar results.
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