VIIRS Application to Cloud Cover at Night in Cool Season

The Visible/Infrared Imager/Radiometer Suite (VIIRS) longwave infrared (11.5 micron)channel provided 1 km resolution imagery across most of the U.S. on October 6, 2012 at 0818 UTC.  In the upper Midwest, Canada and Appalachians, high clouds associated with a trough and trailing front are easily seen.  A variety of clouds are also apparent in the Gulf, lower plains states and the Southwest.  With colder surface temperatures becoming more common in the Fall season, other cloud features may not be as apparent with this channel.

VIIRS Longwave IR channel (11.5 micron)

VIIRS Longwave IR channel (11.5 micron) over U.S. on October 6, 2012 at 0818 UTC

The VIIRS short-wave (3.8 micron) channel shows similar features and hints at more clouds associated with the front extending through the Tennessee and Mississippi valleys and into Texas.

VIIRS Short-wave Infrared Channel (3.8 micron)

VIIRS Short-wave Infrared Channel (3.8 micron) over U.S. on October 6, 2012 at 0818 UTC.

VIIRS has a low-light sensor that is able to detect cloud features at night via reflected moonlight.  Note how the clouds and their extent are more apparent via the day-night band from this low-light sensor compared to the infrared examples above. In addition, city lights and other emitted light are captured by the “day-night band reflectivity” product.  In cloudy areas some of these light sources are blocked or obscured.  NASa/SPoRT is transitioning VIIRS channels to NWS partners for evaluation, including this low-light imagery for mesoscale analysis at night of clouds and other features.

VIIRS Day-Night Band

VIIRS Day-Night Band from the low-light sensor over U.S. on October 6, 2012 at 0818 UTC. Moonlight provides light that is reflected by the clouds. City lights and other ground-based sources are also apparent. Cloud cover is more readily apparent than using the IR channels alone.

The Suomi National Polar-orbiting Partnership (NPP) satellite was successfully launched on 28 October 2011. It is a bridge mission toward the Joint Polar Satellite System (JPSS), which is the US contribution to the next generation polar-orbiting operational environmental satellite system (to be coordinated with EUMETSAT). The Visible/Infrared Imager/Radiometer Suite (VIIRS) is one of five instruments onboard NPP.

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