Determination of ICESat-2 Aerosol Type and Cloud Phase Using MERRA-2 Reanalysis Data

In addition to the detailed altimetry products of the Ice, Cloud, and Land Elevation Satellite 2 (ICESat-2), basic atmospheric products have been developed, including calibrated backscatter profiles and cloud and aerosol layer detection. With being limited to a single 532nm wavelength without depolarization, feature subtyping and extinction retrievals are not feasible using heritage space-based lidar algorithms such as employed by NASA’s Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) (2006-2023) and Cloud-Aerosol Transport System (CATS) (2015-2017). To allow for the classification of cloud phase and aerosol type for detected ICESat-2 cloud and aerosol layers, we sample Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) reanalysis along the ICESat-2 orbit. Using cloud phase and aerosol type climatologies, we show MERRA-2-assisted feature subtypes can produce similar global distributions of cloud phase and aerosol type. Orbital coincidences between ICESat-2 and CALIOP show these model assisted feature subtypes compare favorably to those determined by CALIOP and its algorithms. Expanding the atmospheric products from ICESat-2 to include cloud phase and aerosol type will allow for lidar ratios to be assigned, facilitating the future development of layer optical depths.