Temporal consistency of lidar observations during aerosol transport events in the framework of the ChArMEx/ADRIMED campaign at Minorca in June 2013

We performed synergetic daytime and nighttime active and passive remote-sensing observations at Minorca (Balearic Islands, Spain), over more than 3 weeks during the Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Effect in the Mediterranean (ChArMEx/ADRIMED) special observation period (SOP 1a, June-July 2013). We characterized the aerosol optical properties and type in the low and middle troposphere using an automated procedure combining Rayleigh-Mie-Raman lidar (355, 387 and 407aEuro-nm) with depolarization (355aEuro-nm) and AERONET Cimel(A (R)) sun-photometer data. Results show a high variability due to varying dynamical forcing. The mean column-averaged lidar backscatter-to-extinction ratio (BER) was close to 0.024aEuro-sr(-1) (lidar ratio of similar to aEuro parts per thousand 41.7aEuro-sr), with a large dispersion of +/- 33aEuro-% over the whole observation period due to changing atmospheric transport regimes and aerosol sources. The ground-based remote-sensing measurements, coupled with satellite observations, allowed the documentation of (i) dust particles up to 5aEuro-km (above sea level) in altitude originating from Morocco and Algeria from 15 to 18 June with a peak in aerosol optical thickness (AOT) of 0.25aEuro-+/- aEuro-0.05 at 355aEuro-nm, (ii) a long-range transport of biomass burning aerosol (AOTaEuro-aEuro parts per thousand= aEuro-0.18aEuro-+/- aEuro-0.16) related to North American forest fires detected from 26 to 28 June 2013 by the lidar between 2 and 7aEuro-km and (iii) mixture of local sources including marine aerosol particles and pollution from Spain. During the biomass burning event, the high value of the particle depolarization ratio (8-14aEuro-%) may imply the presence of dust-like particles mixed with the biomass burning aerosols in the mid-troposphere. For the field campaign period, we also show linearity with SEVIRI retrievals of the aerosol optical thickness despite 35aEuro-% relative bias, which is discussed as a function of aerosol type.