Operational Assimilation of Aerosol Optical Depth from NPP VIIRS in a Global Aerosol Model

The Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on board the Suomi National Polar-orbiting Partnership (NPP) satellite platform represents the next generation of polar orbiting operational capability for aerosol observation. The heritage of the VIIRS sensor is mainly from the NOAA Advanced Very High Resolution Radiometer (AVHRR) and the NASA Moderate Resolution Imaging Spectroradiometer (MODIS), but VIIRS incorporates several improvements over those sensors, most notably higher spatial resolution. We describe a processing system to ingest observations of aerosol optical depth (AOD) from VIIRS for assimilation into a global aerosol model using the Navy Variational Data Assimilation System for AOD (NAVDAS-AOD). Improvements to analysis and forecast of aerosols from inclusion of the NPP VIIRS data are demonstrated. The impact of VIIRS aerosol data characteristics on pre-processing strategies and forecast impact is analyzed and discussed, with special attention paid to the impact of spatial resolution on data assimilation outcomes. The role and potential of VIIRS within the current and future constellation of aerosol observing satellite systems is discussed and illustrated with examples from NAVDAS-AOD.