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Radiative effect of aerosols above the northern and southern Atlantic Ocean as determined from shipborne lidar observations
Author(s) -
Kanitz T.,
Ansmann A.,
Seifert P.,
Engelmann R.,
Kalisch J.,
Althausen D.
Publication year - 2013
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2013jd019750
Subject(s) - aerosol , troposphere , lidar , radiative transfer , radiative forcing , atmospheric sciences , environmental science , middle latitudes , angstrom exponent , boundary layer , latitude , climatology , meteorology , geology , geography , physics , remote sensing , geodesy , thermodynamics , quantum mechanics
The direct solar radiative effect of aerosols over the Atlantic Ocean was investigated on the basis of aerosol Raman/polarization lidar observations aboard the research vessel Polarstern between Germany (50°N) and either South America (50°S) or South Africa (40°S) in 2009 and 2010. First, a case study of complex aerosol conditions with marine aerosol, dust, and smoke particles in the boundary layer and free troposphere is presented to demonstrate that detailed knowledge of aerosol layering (boundary layer, free troposphere) and aerosol mixing state is required for an accurate determination of the resulting radiative effects. A statistical analysis based on all lidar observations revealed the highest daily mean radiative effect (−43±59 W m −2 at the surface, −14±18 W m −2 at top of atmosphere) in the latitudinal belt from 0°N–15°N in the Saharan dust outflow region. Mean aerosol radiative effects of the polluted northern and clean southern midlatitudes were contrasted. In the northern midlatitudes, the averaged aerosol radiative effect of all simulations was −24±33 W m −2 at the surface which is a factor of 1.6 higher than at similar southern hemispheric latitudes. The simulations based on the lidar observations are in good agreement with colocated pyranometer measurements.