Calendar Event Details
AEROCENTER: Peter Colarco
Affiliation: NASA GSFC, Code 614
Event Date: Tuesday, October 27, 2015
Location: G133
Time: 11:00 AM
Using the NASA GEOS-5 MERRAero Aerosol Reanalysis to Understand the OMI OMAERUV Aerosol Products
The OMI instrument onboard the NASA Aura spacecraft makes wide-swath, near-global daily observations of gases and aerosols. The OMAERUV retrieval algorithm retrieves aerosol properties based on the observed 354 and 388 nm reflectances. These observations show sensitivity to aerosol absorption properties, and the retrieval products include aerosol optical depth and single scattering albedo, but have dependencies on assumed aerosol models and aerosol height. We have previously used the NASA GEOS-5 aerosol reanalysis (MERRAero) to simulate the top of atmosphere radiances at 354 and 388 nm at the OMI viewing geometry under clear sky conditions. GEOS-5 incorporates the GOCART aerosol mechanism, which simulates the lifecycle and optical properties of dust, sea salt, sulfate, and carbonaceous aerosols. MERRAero is a replay of the GEOS-5 model, using GOCART and driven by the MERRA assimilated meteorology, and assimilating MODIS-derived aerosol optical depth as a constraint on the total aerosol loading. From the simulated radiances we have constructed a model version of the OMI UV aerosol index (AI), and comparisons to the observed AI have suggested improvements in the assumptions of aerosol optical properties made in GEOS-5, which have since been incorporated in the model. Here we review that work and discuss its extension to being used as a tool for understanding the OMI operational aerosol retrieval algorithms, specifically the OMAERUV algorithms. For example, using the MERRAero simulated radiances and AI as a known “truth” we have provided those simulated radiances to the OMI retrieval algorithms. Differences between the simulated AI and the recovered AI from the OMI algorithms suggest the importance of differences in assumptions in both sets of calculations, such as of the atmospheric pressure profile. A further extension of this work is to compare the retrieve absorbing AOD from the OMI algorithms ingesting the simulated radiances to those calculated directly in MERRAero. The status of this work and future directions will be presented.
Posted or updated: Thursday, October 22, 2015
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