Particle Property Data Quality Flags for the MISR Aerosol Product

The MISR instrument aboard the NASA Earth Observing System's Terra satellite has the unique capability to retrieve aerosol properties under favorable conditions. General aerosol type retrieval quality guidelines are provided in the MISR Data Quality Statement and related publications. Here we report on the steps we are taking to provide an aerosol-type data quality flag, to be provided with each individual retrieval result. Some factors affecting retrieval quality that can be assessed pre-retrieval are the number of cameras available, the range of scattering angles and surface conditions such as shallow water or seasonal coastal runoff. Factors that must be assessed post-retrieval include low values of retrieved optical depth and the number and type of mixtures successfully passing the MISR algorithm acceptance criteria. Regional monthly plots with MISR measurements binned at 0.5 degree resolution with color-coded stratification of one or more parameters is the main method for identifying locations and times where particle properties are retrieved. Individual MISR values such as mid-visible AOD, number and type of mixtures passing, number of cameras used, the range and maximum scattering angles are plotted individually or as joint distributions. Initially, thresholds and conditions are determined for each MISR parameter separately. Finally, MISR parameters are combined for a given month and region, with their thresholds, to show the overall quality of the retrieval for determining particle properties. Multi-month summaries for more than twelve years of MISR data will aid in assessing quality. Seasons and regions that regularly show poorly constrained aerosol type results are identified, as are times and places where particle property information can be used with confidence. This work is performed in part at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration and in part at the NASA Goddard Space Flight Center.