A Raman lidar system performed routine measurements of suspended aerosols particles in the planetary Boundary Layer and the free troposphere (0-5 km) over Thessaloniki (40.5 deg N,22.9 deg E) in the frame of the EU funded EARLINET project,since mid-2

摘要

Polar Stratospheric Clouds at altitudes roughly between 16 and 25 km convert chlorine reservoir trace gases into active chlorine by heterogeneous chemical reactions [Borrmann et al.,1997] ultimately giving rise to the spring time polar ozone loss.These clouds form through heterogeneous nucleation on the lower stratospheric background aerosol.In order to perform in-situ measurements of lower stratospheric and upper tropospheric aerosols two low-pressure Condensation PArticle counter Systems (COPAS) have been designed along Wilson et al.,1983,and were implemented aboard the Russian M-55 high-altitude research aircraft Geophysica (with a ceiling of 22 km) for fully automated operation.Each of the COPASes consists of two independent channels,one of which can be heated to ~200°C in order to distinguish between non-volatile and total aerosol particle number.All instrument channels have been calibrated and characterized by laboratory experiments.In addition a modified FSSP-300 [Borrmann et al.,2000] (or alternatively a FSSP-100) optical particle counting instrument was operated on Geophysica to measure aerosol and cloud particle size distributions.In-situ data originating from 10 stratospheric flights were obtained during field campaigns in mid-latitudes (Forli,Italy,in July and October 2002) and the polar region (Kiruna,Sweden,January and February 2003) from inside and outside of the polar vortex.These data represent ambient background conditions,cirrus clouds,as well as aerosols and contrails from the air traffic corridor over Italy.During several flights in the polar stratosphere Geophysica sampled its own exhaust plume at cruising altitude.