Retrieval of atmospheric backscatter and extinction profiles with the aladin airborne demonstrator (A2D)

¹ European Space Agency (ESA-ESTEC), 2200 AG Noordwijk, The Netherlands
² German Aerospace Center (DLR), Institute of Atmospheric Physics, Oberpfaffenhofen, 82234 Wessling, Germany

^* alexander.geiss@esa.int

Published online: 13 April 2018

Abstract

By the end of 2017, the European Space Agency (ESA) will launch the Atmospheric laser Doppler instrument (ALADIN), a direct detection Doppler wind lidar operating at 355 nm. An important tool for the validation and optimization of ALADIN’s hardware and data processors for wind retrievals with real atmospheric signals is the ALADIN airborne demonstrator A2D. In order to be able to validate and test aerosol retrieval algorithms from ALADIN, an algorithm for the retrieval of atmospheric backscatter and extinction profiles from A2D is necessary.

The A2D is utilizing a direct detection scheme by using a dual Fabry-Pérot interferometer to measure molecular Rayleigh signals and a Fizeau interferometer to measure aerosol Mie returns. Signals are captured by accumulation charge coupled devices (ACCD). These specifications make different steps in the signal preprocessing necessary.

In this paper, the required steps to retrieve aerosol optical products, i. e. particle backscatter coefficient β_p, particle extinction coefficient α_p and lidar ratio S_p from A2D raw signals are described.