Advanced retrieval of aerosol vertical profiles using synergy of EarthCARE ATLID and passive spaceborne observations

We present the “EarthCARE ATLID and MSI Instruments Synergy for Advanced Retrieval of Aerosol Vertical Profiles” (ECAMS) project, which aims to enhance the integration of passive and active observations by combining Level 1 (L1) data from EarthCARE and various imagers. This project focuses on aerosol retrieval through the fusion of L1 observations from lidar (ATLID) and imagers on EarthCARE (MSI) and PACE (SPEXone, HARP-2). This approach, though methodologically promising, presents significant technical challenges and requires substantial resources.

Atmospheric aerosols are major drivers of climate change and have significant impacts on human health. Global information on aerosol properties is primarily obtained from space-based measurements. Passive remote sensing involves spectral observations of top-of-atmosphere reflectance at various angles, providing data on aerosol quantity, particle size and morphology, with limited sensitivity to its vertical distribution. Conversely, active lidar observations excel in detecting aerosol vertical distribution but lidar stand-alone retrievals require assumptions about aerosol size and morphology, making collocated radiometric measurements crucial for their comprehensive interpretation.

Current methods for synergetic aerosol property retrievals mainly focus on ground-based active and passive observations and do not fully leverage recent advancements in lidar technology, such as high spectral resolution lidars (HSRLs). Moreover, existing methods lack the flexibility to integrate various lidar configurations with passive measurements for space-based observations. ECAMS aims to address these limitations by developing new methods for generating global aerosol vertical distribution products with improved accuracy, aiding climate model validation. The project’s synergetic retrieval approach uses highly optimized forward models (including aerosol and surface reflectance) and the statistical estimation framework of the open-source GRASP (Generalized Retrieval of Atmosphere and Surface Properties) software.

The ECAMS framework is designed for adaptability, enabling the synergistic processing of various active and passive satellite observations across different spatial, vertical, and spectral resolutions and ranges. It serves as platform for advancing remote sensing of atmospheric and surface structures, providing a virtual laboratory for diverse remote sensing research and applications.

One of the project’s objectives is to support and complement synergy developments in the context of ESA AIRSENSE project and its studies on aerosol-cloud interactions, in collaboration with the EC CleanCloud and CERTAINTY projects. Ongoing developments and results will be presented and discussed.