Author:
|
Ansmann, Albert; Bösenberg, Jens; Chaikovsky, Anatoli; Comerón Tejero, Adolfo; Eckhardt, Sabine; Eixmann, Ronald; Freudenthaler, Volker; Ginoux, Paul; Komguem, Leonce; Linné, Holger; López Márquez, Miguel Ángel; Matthias, Volker; Mattis, Ina; Mitev, Valentin
|
Abstract:
|
The spread of mineral particles over southwestern, western, and central Europe
resulting from a strong Saharan dust outbreak in October 2001 was observed at
10 stations of the European Aerosol Research Lidar Network (EARLINET). For the first
time, an optically dense desert dust plume over Europe was characterized coherently
with high vertical resolution on a continental scale. The main layer was located above
the boundary layer (above 1-km height above sea level (asl)) up to 3–5-km height, and
traces of dust particles reached heights of 7–8 km. The particle optical depth typically
ranged from 0.1 to 0.5 above 1-km height asl at the wavelength of 532 nm, and
maximum values close to 0.8 were found over northern Germany. The lidar observations
are in qualitative agreement with values of optical depth derived from Total Ozone
Mapping Spectrometer (TOMS) data. Ten-day backward trajectories clearly indicated the
Sahara as the source region of the particles and revealed that the dust layer observed,
e.g., over Belsk, Poland, crossed the EARLINET site Aberystwyth, UK, and southern
Scandinavia 24–48 hours before. Lidar-derived particle depolarization ratios,
backscatter- and extinction-related A ° ngstro¨m exponents, and extinction-to-backscatter
ratios mainly ranged from 15 to 25%, 0.5 to 0.5, and 40–80 sr, respectively, within the
lofted dust plumes. A few atmospheric model calculations are presented showing the dust
concentration over Europe. The simulations were found to be consistent with the
network observations. |