The EarthCARE ATLID profile processors

ATLID (Atmospheric Lidar) is the lidar to be embarked on the Earth Clouds and Radiation Explorer (EarthCARE) mission. EarthCARE is a joint ESA-JAXA mission and will embark a cloud/aerosol lidar (ATLID), a cloud-profiling Radar (CPR) a multispectral cloud/aerosol imager (MSI) and a three—view broad-band radiometer (BBR). ATLID is a 355nm high-spectral-resolution, polarization sensitive lidar.

The accurate retrieval of aerosol and cloud properties from space-based lidar is a challenging endeavor, even when the extra information provided by an HSRL system is exploited. The generally low signal-to-noise (SNR) ratios involved coupled with the need to respect the structure of the aerosol and cloud fields being sensed are particular challenges.

Over the past several years, cloud/aerosol algorithms have been developed for ATLID that have focused on the challenge of making accurate retrievals of cloud and aerosol extinction and backscatter specifically addressing the low SNR nature of the lidar signals and the need for intelligent binning/averaging of the data. Two of these ATLID processors are A-FM (ATLID featuremask) and A-PRO (ATLID profile processor). A-FM uses techniques adapated from the field of image processing to detect the presence of targets at high resolution while A-PRO (using A-FM as input) preforms a multi-scale optimal-estimation technique in order to retrieve both aerosol and cloud extinction and backscatter profiles.

Adaptations of the A-FM and A-PRO processors have been developed for Aeolus (called AEL-FM and AEL-PRO, respectively) and have been introduced into the Aeolus L2a operational processor. In this presentation A-FM and A-PRO will be described. Results based on simulated data for A-FM and A-PRO and results using AEL-FM and AEL-PRO using Aeolus observations will be presented and discussed.