by Athina Argyrouli

From January 18th to February 13th, I was hosted at the University of Hertfordshire (UH) for a secondment aiming to apply the inversion algorithm to the HygrA-CD campaign lidar data. The microphysical properties of aerosols are critical for examining aerosols' ability to act as Cloud Condensation Nuclei (CCN). For the purposes of my Ph.D. thesis, we need to retrieve aerosol microphysics at lofted layers within the Planetary Boundary Layer (i.e., at the so-called residual layer).

The goal of this visit was to retrieve aerosols' microphysical properties (e.g., effective radius, number concentration) from optical data (i.e., 3 backscatter coefficients & 2 extinction coefficients). Vertical profiles of aerosols' optical properties were retrieved with the use of Single Calculus Chain (SCC), a dynamic processing tool developed for all lidar stations within the European Aerosol Research Lidar Network (EARLINET). The lidar inversion algorithm was applied to homogeneous aerosol layers and subsets from the solution space with low discrepancy (<1%) have been evaluated from the physical point-of-view.

During this 4-week secondment to UH, I also got the opportunity to give a talk about my Ph.D. topic to the scientific community in the School of Physics, Astronomy and Mathematics as part of the weekly seminars organized by the UH. I am thankful to Professor Detlef Müller who offered me a couple of discussion hours on a daily basis. Before leaving UK, at the end of the secondment, we set specific goals for the near future towards the improvement of the optical data.

Last but not least, I cannot neglect to mention that it was a nice circumstance to meet a new member of the group, Dr. Matthias Tesche, who provided me with a copy of his Ph.D. thesis on aerosol optical properties vertically resolved from ground-based remote sensing. Both Matthias and Detlef ensured very good working conditions for me in order to have a productive secondment at the university.