Remote sensing measurements of the volcanic ash plume over Poland in April 2010

This work provides information on selected optical parameters related to volcanic ash produced during the eruption of the Eyjafjöll volcano in Iceland in 2010. The observations were made between 16 and 18 April 2010 at four stations representative for northern (Sopot), central (Warsaw, Belsk) and south-eastern (Strzyzow) regions of Poland. The largest ash plume (in terms of aerosol optical thickness) over Poland was observed at night of 16/17 April 2010 in the layer between 4 and 5.5 km a.s.l. The highest values of the aerosol extinction coefficient reached 0.06–0.08 km−1 at 532 nm (based on lidar observations in Warsaw) and 0.02–0.04 km−1 at 1064 nm (based on ceilometer observations in Warsaw). The corresponding optical thickness due to volcanic ash reached values of about 0.05 at 532 nm and about 0.03 at 1064 nm. These values are similar to those reported for the Belsk station based on lidar observations. The ash mass concentration estimated based on the maximum aerosol extinction coefficient reached 0.22 ± 0.11 mg m−3. This value is significantly lower than the limit (2 mg m−3) for the aircraft operation.