ADM-Aeolus retrieval algorithms for aerosol and cloud products

Abstract

A B S T R A C T ADM-Aeolus, the wind Lidar under development at ESA, is a High Spectral Resolution Lidar that additionally provides separated information on particles (Mie channel) and molecules (Rayleigh channel). Lidar signals will be accumulated in vertical range bins in order to reach sufficient signal-to-noise ratio for reliable wind estimates. The vertical range bin integration may vary from 250 m near the surface up to 2 km in the upper troposphere and lower stratosphere. Significant attenuation in a range bin changes the nature of the retrieval problem. The commonly used Lidar inversion techniques appear to be inadequate to process bin-accumulated signals. This paper presents the 'L2A processor', conceived to use ADM-Aeolus signals to provide information on aerosol and cloud layers optical properties. The altitude, geometrical depth, optical depth, backscatter-to-extinction ratio and scattering ratio are to be retrieved. The L2A processor algorithms provide a new formulation to the inverse problem for various filling cases of a range bin and it includes a credibility criterion (CC) in order to select the best filling approximation. The effective vertical resolution can be two to four times better than the ADM-Aeolus range bins. The basic concept, the processing algorithms, numerical examples and sensitivity tests are here presented.

Lidar-Measured Wind Profiles: The Missing Link in the Global Observing System

“…Because DWL measurements rely on aerosol backscatter returns to determine line-of-sight velocities, they provide an excellent opportunity to retrieve profiles of aerosol backscatter and derived aerosol extinction (Ansmann et al 2007;Flamant et al 2008). Because DWL measurements rely on aerosol backscatter returns to determine line-of-sight velocities, they provide an excellent opportunity to retrieve profiles of aerosol backscatter and derived aerosol extinction (Ansmann et al 2007;Flamant et al 2008).…”

“…Several studies have demonstrated the potential impact of the ADM-Aeolus instrument on NWP forecast quality. Furthermore, the ADM-Aeolus instrument can also give information on aerosol concentrations in the atmosphere as discussed by Ansmann et al (2007) and Flamant et al (2008). Žagar et al (2004) emphasized the potential impact in the tropics and showed how single lineof-sight wind measurements and mass information can complement each other.…”

Airborne Multiwavelength High Spectral Resolution Lidar (HSRL-2) observations during TCAP 2012: vertical profiles of optical and microphysical properties of a smoke/urban haze plume over the northeastern coast of the US

“…Space missions of HSRL systems will be launched by NASA (http://www.nasa-usa.de/mission_pages/ station/research/experiments/1037.html) and ESA (Stoffelen et al, 2005;Ansmann et al, 2007;Flamant et al, 2008) in the next couple of years and . These lidar missions however do not provide the necessary number of measurement channels in order to carry out detailed investigations of particle microphysical properties.…”

The ADM-Aeolus wind retrieval algorithms

“…Thus, L2B products are intermediate between L1B and L2C data. Level‐2A products (information on aerosol and cloud layer optical properties) are described by Flamant et al (2008).…”