Predicted Performance of NPOESS/NPP Aerosol Algorithms

The Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report clearly states that the direct and indirect effects of atmospheric aerosols still accounts for the largest uncertainty in global mean radiative forcing. Satellite based observation of global aerosol distribution remain the best means of reducing these uncertainties. The National Polar-orbiting Operational Environmental Satellite System [NPOESS] is being developed as a follow-on system to the current NOAA Polar Orbiting Environmental Satellite (POES) and the DoD Defense Meteorological Satellite Program (DMSP) systems. Measurements of the atmospheric aerosols from NPOESS, will come from the VIIRS instrument. The 22 VIIRS spectral bands include 16 radiometric bands plus 5 imaging bands and a day-night band. The aerosol related Environmental Data Records (EDRs) will be derived primarily from the radiometric channels covering the visible through the short-wave infrared spectral regions (412 to 2250 nm). The primary aerosol products will be the aerosol optical thickness, aerosol particle size parameter, and the identification and typing of suspended matter. These aerosol algorithms and their derivation will be described including recent updates due to improved performance demonstrated by the MODIS collection 5 aerosol algorithm modifications. Pre-launch estimations of on-orbit performance have been derived using both proxy and synthetic data. The proxy data technique uses MODIS level 1B data to simulate the radiances which will be measured by VIIRS and compares the retrieved aerosol properties with AERONET match-up data used for MODIS aerosol product validation. The synthetic data technique uses a radiative transfer model to simulate VIIRS radiance data from a global data set and compares the retrieved aerosol properties with predefined truth.