Retrieval algorithm for aerosol effective height from the Geostationary Environment Monitoring Spectrometer (GEMS)

Abstract

An algorithm for aerosol effective height (AEH) was developed for operational use with observations from the Geostationary Environment Monitoring Spectrometer (GEMS). The retrieval technique uses the slant column density of the oxygen dimer (O2–O2) at 477 nm, which is converted into AEH after retrieval of aerosol and surface optical properties from GEMS operational algorithms. The retrieved AEHs provide continuous vertical information on severe dust plumes over East Asia with reasonably good validation results and the collection of plume height information for anthropogenic aerosol pollutants over India. Compared to the AEH retrieved from Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP), the retrieval results show a bias of −0.03 km with a standard deviation of 1.4 km for the AEH difference over the GEMS observation domain from January to June 2021. The AEH difference depends on aerosol optical properties and surface reflectance. Compared to the aerosol layer height obtained from the Tropospheric Monitoring Instrument (TROPOMI), differences of 1.50 ± 1.08 km, 1.59 ± 1.22 km, and 1.71 ± 1.24 km were obtained for pixels with single-scattering albedo (SSA) < 0.90, 0.90 < SSA < 0.95, and SSA > 0.95, respectively.