Optical Lab for Lidar Applications

The Optical Lab for Lidar Applications (OLALA) is a Leibniz Junior Research Group founded by the Leibniz Association (2023 – 2028). The goal of OLALA is the fundamental understanding of the optical properties of mineral dust (regarding the backscatter) needed for global observations with active remote sensing from ground and space. The project will substantially support the dust optical modelling by developing realistic size/shape parameterizations. In order to achieve these objectives, a new laboratory will be constructed to measure the depolarization ratio of size-selected natural dust samples at 180° scattering angle at the relevant aerosol lidar wavelengths of 355, 532 and 1064 nm. The laboratory efforts will be strongly linked to improvements of optical models of irregularly shaped particles to maximize the impact of the laboratory investigations for the active remote sensing community.

Project list

Two subprojects are tackled by the OLALA research group:

1. OLALA-Lab
   The setup of a new scattering laboratory to measure the depolarization ratio of size selected mineral dust particles in the exact backscatter. Measurements at a scattering angle of 180° are rarely performed but of fundamental importance for lidar applications. For the first time, all lidar-relevant wavelengths of 355, 532 and 1064 nm will be used. The novel approach of using size-segregated dust samples will allow to study the influence of the particle size on the spectral depolarization ratio.
    
2. OLALA-Model
   An optical model that realistically describes mineral dust optical properties at 180° is not available yet. The realistic shape parameterizations for mineral dust which will be developed within the project from the laboratory efforts will lead to more representative particle size distributions estimates (e.g., fine and coarse mode distribution), mass concentrations and aerosol typing from active remote sensing with lidar. The laboratory investigations provide information on the particle size, shape and refractive index which will be implemented in selected optical models.