Tropospheric Vertical Profiles of Aerosol Optical, Microphysical and Concentration Properties in the Frame of the Hygra-CD Campaign (Athens, Greece 2014): A Case Study of Long-Range Transport of Mixed Aerosols

¹ Laser Remote Sensing Laboratory, National Technical University of Athens, 15780 Athens, Greece
² University of Hertfordshire, Hatfield, Hertfordshire, AL10 9AB, UK
³ INOE, National R&D Institute for Optoelectronics, Magurele, Romania
⁴ Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, Switzerland
⁵ IAASARS, National Observatory of Athens, Greece

^* Email: apdlidar@central.ntua.gr

Published online: 7 June 2016

Abstract

Combined multi-wavelength aerosol Raman lidar and sun photometry measurements were performed during the HYGRA-CD campaign over Athens, Greece during May-June 2014. The retrieved aerosol optical properties (3 aerosol backscatter at 355-532-1064 nm and 2 aerosol extinction profiles at 355-532 nm) were used as input to an inversion code to retrieve the aerosol microphysical properties (effective radius r_eff and number concentration N) using regularization techniques. Additionally, the volume concentration profile was derived for fine particles using the LIRIC code. In this paper we selected a complex case study of long-range transport of mixed aerosols (biomass burning particles mixed with dust) arriving over Athens between 10-12 June 2014 in the 1.5-4 km height. Between 2-3 km height we measured mean lidar ratios (LR) ranging from 45 to 58 sr (at 355 and 532 nm), while the Ångström exponent (AE) aerosol extinction-related values (355nm/532nm) ranged between 0.8-1.3. The retrieved values of r_eff and N ranged from 0.19±0.07 to 0.22±0.07 μm and 460±230 to 2200±2800 cm^-3, respectively. The aerosol linear depolarization ratio (δ) at 532 nm was lower than 5-7% (except for the Saharan dust cases, where δ~10-15%).