National Observatory of Athens

EVE Lidar

PI: Nikolaos Siomos Operators: Peristera Paschou Parameters: Particle Backscatter Coefficient(355nm), Particle Extinction Coefficient(355nm), Linear Depolarization Ratio(355nm Volume &Particle), Circular Depolarization Ratio(355nm Volume&Particle)

EVE lidar is a combined linear/circular polarization system, tailored to evaluate the spaceborne ALADIN Doppler lidar system. EVE has been developed by RAYMETRICS S.A. The goal is to provide the ESA-Aeolus mission with a flexible, mobile reference ground-based lidar system cap able of providing well-characterized fiducial reference measurements of the aerosol optical properties. ALADIN detects only the co-polar compon ent of the backscattered circularly polarized emission. This leads to underestimations when comparing with the total aerosol backscatter measured by nearly all conventional ground-based lidar systems, especially for highly depolarizing aerosol scenes. While lidars that measure the aerosol depolarization do exists, they mainly rely on linear polarization. This can lead to uncertainties in the evaluation the co-polar backscatter of AEOLUS with such measurements when probing layers that contain oriented scatterers (e.g. clouds, ice crystals) or that are dense enough for multiple scattering to take place. EVE lidar operates using both linear and circular polarization and can bridge the gap between the conventional lidars and AEOLUS by quantifying these uncertainties. It can also evaluate the particle backscatter/extinction retrievals of Aeolus, and even the upcoming EarthCARE product in the future.