VIIRS constant spatial-resolution advantages

The Suomi National Polar-orbiting Partnership NPP Visible Infrared Imager Radiometer Suite VIIRS was launched on 28 October 2011, nearly 20 years after the conceptual definition began at the Hughes Aircraft Company's Santa Barbara Research Center. Constrained off-nadir pixel growth, producing constant or near-constant VIIRS spatial resolution over the entire scan swath, is a patented design feature that dramatically improves imaging radiometry compared to VIIRS predecessors. VIIRS ground-projected east–west across the orbit track and north–south along the orbit track pixel dimensions are constrained to within a factor of two from nadir to ±1500 km off-nadir edge of scan in all 22 VIIRS spectral bands. The capability is a valuable improvement to previous systems' six-fold across-track pixel growth over narrower swaths, while improving signal-to-noise ratio SNR without larger optics. The technique allows the VIIRS day/night band DNB to offer nearly 9-to over 50-fold finer and truly constant area spatial resolution with enhanced sensitivity and dynamic range compared with the Defense Meteorological Satellite Program DMSP Operational Linescan System OLS. This article reviews constant resolution from concept to VIIRS implementation and compares several VIIRS applications to similar applications of systems VIIRS replaces to demonstrate advantages of the new capability.