Observation of non-spherical ultragiant aerosol using a microwave radar

Abstract

Observations of ultragiant aerosol particles performed at the CNR-IMAA Atmospheric Observatory using a Ka-Band Doppler radar in four different periods from 19 April to 13 May 2010 are presented. In the reported cases, the aerosol radar signatures are characterized by a similar scenario. In particular, the linear depolarization ratio shows values higher than -4 dB probably related to the effect of bulk density and to the non-sphericity of the ultragiant particles. During the same period, volcanic aerosol layers coming from Eyjafjallajkull volcano were observed over most of European countries, including Southern Italy, using lidar technique. The observation of volcanic layers over Potenza by multi-wavelength Raman lidar measurements suggests a volcanic origin of the ultragiant aerosol particles observed by the radar, revealing that these particles might travel in the atmosphere for more than 4000 km after their injection in the atmosphere. © 2010 by the American Geophysical Union.