The Day / Night Visible Sensor aboard NPOESS VIIRS (Invited Presentation)

The Visible/Infrared Imager/Radiometer Suite (VIIRS) is the next generation visible and infrared sensor that will be flown on the National Polar-orbiting Operational Environmental Satellite System (NPOESS) and NPOESS Preparatory Satellite (NPP) platforms. The majority of the twenty-two channels aboard VIIRS are derived from similar channels from two predecessor instruments, the NOAA Advanced Very High Resolution Radiometer (AVHRR) and Earth Observation System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS). However, the unique VIIRS Daynight channel is a refinement of visible sensing capability from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). The Daynight sensor will measure visible radiances from the earth at any time of day or night, making gain adjusments to calibrate a huge range of radiances that occur within the lunar and solar cycles. Some of the VIIRS Daynight channel improvements compared to the OLS will be better gain control, smaller instantaneous field of view, better calibration, collocation with other multispectral measurements from VIIRS and other NPOESS sensors, increased quantitization, reduced blur, generally smaller pixel size, and elimination of pixel size variation across the view swath. First, the paper will contain a description of the Daynight sensor, contrasting the engineering with that of the OLS. Then it will show image examples from the OLS and anticipate improvements with VIIRS. The focus will be on nighttime applications. It will investigate cloud imaging, land surface effects, analysis of ice and snow on the surface of the earth, lightning in clouds, fire detection, and imaging of smoke and dust. We will discuss how other VIIRS channels will add a multispectral synergy to the measurements from the Daynight channel, enabling a variety of new environmental products.