The Airborne Demonstrator for the Direct-Detection Doppler Wind Lidar ALADIN on ADM-Aeolus. Part I: Instrument Design and Comparison to Satellite Instrument

Abstract

The global observation of profiles of the atmospheric wind speed is the highest-priority unmet need for global numerical weather prediction. Satellite Doppler lidar is the most promising candidate to meet the requirements on global wind profile observations with high vertical resolution, precision, and accuracy. The European Space Agency (ESA) decided to implement a Doppler wind lidar mission called the Atmospheric Dynamics Mission Aeolus (ADM-Aeolus) to demonstrate the potential of the Doppler lidar technology and the expected impact on numerical weather forecasting. An airborne prototype of the instrument on ADM-Aeolus was developed to validate the instrument concept and retrieval algorithms with realistic atmospheric observations before the satellite launch. It is the first airborne direct-detection Doppler lidar for atmospheric observations, and it is operating at an ultraviolet wavelength of 355 nm. The optical design is described in detail, including the single-frequency pulsed laser and the two spectrometers to resolve the Doppler frequency shift from molecular Rayleigh and aerosol Mie backscatter. The airborne prototype is representative of the spaceborne instrument, and their specific differences are discussed.

A systematic study of Rayleigh-Brillouin scattering in air, N2, and O2 gases

“…The CRBS techniques were recently extended for measuring the temperature of a flame 22 and for monitoring ∼ 1 nm nano-particles in bulk gases or weakly ionized plasmas 23 . Renewed research on spontaneous RB scattering is driven by the possible applications of LIDAR (light detection and ranging) techniques to obtain the wind speed distributions in the Earth's atmosphere, such as will be pursued by the ADM-Aeolus mission of the European Space Agency (ESA) [24][25][26] , for the temperature LIDAR experiments currently performed by German Aerospace Center (DLR) 27 , as well as for aerosol LIDAR 28 . Experimental measurements on RB scattering profiles of molecular gases, particularly of air as a gas mixture, are required to the highest possible signal-to-noise ratio to test the accuracy of the S6 model, which is proposed to be used in retrieval algorithms of LIDAR applications.…”

On the benefit of airborne demonstrators for space borne lidar missions

“…After realisation of A2D [5], a multi-year pre-launch validation project including ground-based and airborne campaigns on the Falcon ( Fig. 1) was performed.…”

The Measurement of Tropospheric Temperature Profiles using Rayleigh-Brillouin Scattering: Results from Laboratory and Atmospheric Studies

“…The lidar used for this study was not originally built for this purpose, but is actually a Doppler wind lidar, used for validating the instrument of the ADM-Aeolus satellite mission initiated by ESA [10]. However, as it is shown in [11], the instrument is also suited for measuring temperature by means of RB scattering.…”