Global assessment of OMI aerosol single‐scattering albedo using ground‐based AERONET inversion

Abstract

We compare the aerosol single-scattering albedo (SSA) retrieved by the near-UV two-channel algorithm (OMAERUV) applied to the Aura/Ozone Monitoring Instrument (OMI) measurements with an equivalent inversion made by the ground-based Aerosol Robotic Network (AERONET). A recent upgrade of the OMAERUV algorithm incorporates a modified carbonaceous aerosol model, a Cloud-Aerosol Lidar with Orthogonal Polarization-based aerosol height climatology, and a robust aerosol-type identification. This paper is the first comprehensive effort to globally compare the OMI-retrieved SSA with that of AERONET using all available sites spanning the regions of biomass burning, dust, and urban pollution. An analysis of the colocated retrievals over 269 sites reveals that about 46% (69%) of OMI-AERONET matchups agree within the absolute difference of ±0.03 (±0.05) for all aerosol types. The comparison improves to 52% (77%) when only "smoke" and "dust" aerosol types were identified by the OMAERUV algorithm. Regionally, the agreement between the two inversions was robust over the biomass burning sites of South America, Sahel, Indian subcontinent, and oceanic/coastal sites followed by a reasonable agreement over Northeast Asia. Over the desert regions, OMI tends to retrieve higher SSA, particularly over the Arabian Peninsula. Globally, the OMI-AERONET matchups agree mostly within ±0.03 for the aerosol optical depth (440 nm) and UV-aerosol index larger than 0.4 and 1.0, respectively. Possible sources of uncertainty in the OMI retrieval can be the subpixel cloud contamination, assumptions of the surface albedo, and spectral aerosol absorption. We expect further refinement in the OMAERUV algorithm which stands uniquely in characterizing aerosol absorption from space.

GOCI Yonsei aerosol retrieval version 2 products: an improved algorithm and error analysis with uncertainty estimation from 5-year validation over East Asia

“…Thus, aerosol models are constructed more coarsely for SSA than for FMF, and the inversion methods focus on spectral matching of AOD at 550 nm, rather than on SSAoptimized retrieval, such as the OMI aerosol retrieval algorithm using ultraviolet radiation (Torres et al, 2013;Jeong et al, 2016). Nevertheless, the ratio of GOCI V2 SSA to AERONET SSA in a ±0.03 and ±0.05 range is 47.7 and 68.0 % for land and 69.7 and 88.3 % for ocean, respectively, which is comparable to the OMI SSA presented by Jethva et al (2014).…”

Seasonal cycle of desert aerosols in western Africa: analysis of the coastal transition with passive and active sensors

“…Some approximations are used in the numerical inversion algorithm which produce errors named relative errors having a standard deviation of 0.01 (Dubovik et al, 2000). AERONET's SSAs are computed for favorable atmospheric conditions (AOD 440 nm > 0.4 and solar zenith angle > 45 • ) using an algorithm which performs almucantar inversions (Jethva et al, 2014). These data are used to validate remotely sensed AOD and SSA measurements.…”

Estimation of black carbon emissions from Siberian fires using satellite observations of absorption and extinction optical depths

“…The OMAERUV product has been validated on a global scale by comparing OMI-retrieved AOD and SSA with the 15 corresponding data derived from ground-based measurements of the sun-sky photometers at the AERONET sites Jethva et al, 2014). The comparison confirmed that the OMI AOD and SSA retrievals are quite reliable.…”