A Novel Method for Aerosol Product Evaluation for the Stratospheric Aerosol and Gas Experiment (SAGE): Converting Extinction to Backscatter

The Stratospheric Aerosol and Gas Experiment on the International Space Station (SAGE-III/ISS) is the fourth of the SAGE instruments to be put in orbit and was launched in February 2017. SAGE-III/ISS products include aerosol extinction profiles at nine channels (384, 448, 520, 601, 755, 870, 1020, 1555 nm) with vertical resolution of 1 km (0--40 km), and nominal baseline uncertainty of 5%. Evaluation of the aerosol extinction coefficient products has been challenging due to limited reliable extinction observations from other instruments. However, ground-based stratospheric lidars that natively measure backscatter are located around the globe. Herein we present a method for converting SAGE-III/ISS extinction profiles to backscatter profiles using Mie theory as a bridge between the two products. We present an evaluation of the robustness of this new method and compare these SAGE-derived backscatter coefficients to ground-based and satellite-based (e.g. Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP)) lidar products. The analysis covers the SAGE-II (1984-2005) and SAGE-III/ISS (2017-present) data records.