Abstract. Using the Vector LInearized Discrete Ordinate Radiative Transfer (VLIDORT)
code as the main driver for forward model simulations, a first-of-its-kind
data assimilation scheme has been developed for assimilating Ozone
Monitoring Instrument (OMI) aerosol index (AI) measurements into the Naval
Aerosol Analysis and Predictive System (NAAPS). This study suggests that both root mean square error
(RMSE) and absolute errors can be significantly reduced in NAAPS analyses with
the use of OMI AI data assimilation when compared to values from NAAPS
natural runs. Improvements in model simulations demonstrate the utility of
OMI AI data assimilation for aerosol model analysis over cloudy regions and
bright surfaces. However, the OMI AI data assimilation alone does not
outperform aerosol data assimilation that uses passive-based aerosol
optical depth (AOD) products over cloud-free skies and dark surfaces.
Further, as AI assimilation requires the deployment of a
fully multiple-scatter-aware radiative transfer model in the forward
simulations, computational burden is an issue. Nevertheless, the
newly developed modeling system contains the necessary ingredients for
assimilation of radiances in the ultraviolet (UV) spectrum, and our study
shows the potential of direct radiance assimilation at both UV and visible
spectrums, possibly coupled with AOD assimilation, for aerosol applications
in the future. Additional data streams can be added, including data from the
TROPOspheric Monitoring Instrument (TROPOMI), the Ozone Mapping and Profiler
Suite (OMPS), and eventually the Plankton, Aerosol, Cloud and
ocean Ecosystem (PACE) mission.