Tutorial 15:

Profiling the aerosol optical-microphysical and chemical properties using advanced LiDAR techniques

Alex Papayannis, National Technical University of Athens, Greece; Ecole Polytechnique Fédérale de Lausanne, Switzerland

Abstract: Following the invention of lasers, the laser remote sensing (LiDAR) technique has been used to probe the terrestrial atmosphere, and provide the vertical profiles of atmospheric parameters (density, temperature, wind, water vapor, aerosols, gases, etc.). In this tutorial we will quickly review the basic interactions between laser and matter in the atmosphere, giving emphasis on the aerosols and clouds. We will present the working principle of the lidar technique, as well as its main components used in current lidar systems used for tropospheric aerosol and cloud profiling. We will then discuss how the aerosol optical parameters (backscatter and extinction coefficients, depolarization ratio) are retrieved and how we can cluster aerosol layers in different types (biomass burning, dust, marine, continental, etc.). Furthermore, we will then focus on the retrieval of the aerosol microphysical and chemical properties. Finally, the remaining challenges in the field of lidar aerosol profiling and characterization will be discussed, concerning their use in atmospheric radiative models. We will also demonstrate live the lidar technique with the NTUA’s AIAS mobile lidar system. Attendants will get a hands-on experience by aligning the AIAS system and see live the probing of aerosol layers of the atmosphere in the vicinity.

Short bio: Prof. Alex Papayannis is the Director of the Laboratory of Optoelectronics, Lasers and Applications and Research Professor of Atmospheric Physics, Laser Technology and Laser Remote Sensing, at the National Technical University of Athens (NTUA). He is a LiDAR expert, with over 38 years’ experience in LiDAR systems’ design, development and operation. His research interests and experience include the vertical profiling of atmospheric parameters (temperature, density, water vapor, etc.), aerosols, clouds and gases (O3, H2O, glyoxal,) in the troposphere. His research in aerosol profiling and characterization is focused on the aerosol optical, microphysical, chemical and radiative properties by combining passive and remote sensing ground-based and spaceborne techniques. He is founder of the Raymetrics LiDAR S.A., founding member of the European lidar Network (EARLINET), past member of the EARLINET Executive Committee, as well as, past member and current President (2015-2022) of the International Coordination Group for Laser Atmospheric Studies (ICLAS).