AEROSOL OPTICAL DEPTH, WATER VAPOUR CONTENT AND TOTAL OZONE MEASUREMENTS OVER SOFIA (BULGARIA) FROM THREE CAMPAIGNS 2010-2012

This contribution presents the results from three experimental campaigns carried out in June 2010, June 2011 and June 2012 at three sites in the city of Sofia (Institute of Electronics, Astronomical Observatory in the Borisova Gradina Park and National Institute of Geophysics, Geodesy and Geography (NIGGG)). A ceilometer CHM15k, two sun photometers Microtops II and an automatic meteorological station were used during the experiments. Ceilometer backscatter analyses reveal that the height of the mixing layer varied from 1500 m to 2500(3000) m above ground level. The height of the residual layer ranged from 800 m to 2000 m. The stable boundary layer extended to 200-400 m over the campaigns. The aerosol optical depth (AOD) at wavelength lambda = 500 nm ranged from 0.38 to 0.66 in the first campaign and from 0.24 to 0.55 in the second one and from 0.11 to 0.23 in the third one. Corresponding ranges for the water vapour content (WVC) were from 1.26 cm to 2.6 cm. Different types of aerosol optical depth and water vapour content behaviour were observed. The total ozone content (TOC) varied from 240 DU to 370 DU during the campaigns. The groundbased observation from ozonemeter Microtops II with satellite observation of Ozone Monitor Instruments (OMI) over Sofia (Bulgaria) are compared. Our results have implications for further studies of regional climate variability.