Optical Lab for Lidar Applications (OLALA)

The Optical Lab for Lidar Applications (OLALA) is a Leibniz Junior Research Group  (2023 – 2028) funded by the Leibniz Association.

 

Motivation

Mineral dust is globally the most abundant aerosol type in terms of mass, influencing cloud formation and radiation even far away from its source regions. The irregular shape of mineral dust particles is a challenge for optical models. Especially, the scattering properties at exactly 180° backscatter are hard to predict, but needed for height-resolving remote sensing observations with lidar. Up to now, there is no comprehensive data set of the scattering properties at 180° which could be used to test and improve the optical models.

 

Mission

The Optical Lab for Lidar Applications (OLALA) will fill this gap by constructing a new scattering laboratory specialized at measurements of the depolarization ratio in the exact backscattering direction.  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. The laboratory investigations provide information on the particle size, shape and refractive index which will be implemented in selected optical models.

 

Outlook

The gained knowledge will be applied to advanced multiwavelength polarization lidar observations of mineral dust and its mixtures, e.g., collected within PollyNET at Cabo Verde.  The Junior Research Group will close the loop from field observations to laboratory investigations and modelling efforts to better quantify the dust contribution in global field observations from ground and space.