Fog and Low Clouds in Eastern Colorado as seen with GeoColor and Day Night Band NPP VIIRS imagery on 20 Dec 2013

The Suomi NPP VIIRS Day/Night Band (DNB), which can use moonlight to produce visible-light imagery during the nighttime, offers a unique capability that is slated to continue on the JPSS constellation concurrent to the GOES-R era.  This presents intriguing potential for synergy between the DNB and Advanced Baseline Imager.  One can use the imagery just as visible imagery is currently used in the daytime, so there are many applications.  Here we show how fog and low clouds distinctly appear during the nighttime hours using the DNB imagery, shown below first on a larger scale and then zoomed in over Colorado.

DNB imagery over the western half of the CONUS at 0914 UTC on 20 December 2013.

DNB imagery centered over Colorado at 0914 UTC on 20 December 2013.

Lights from the various towns and cities are seen in the DNB imagery.  City lights are also a part of one of the earlier CIRA Proving Ground demonstration imagery known as GeoColor imagery.  GeoColor is intended to be a survey type imagery that has a seamless transition from night to day by combining different bands and background imagery.  The current version uses a static nightime background of city lights (though it will be possible to update to quasi-real time imagery using Polar satellites), as seen in the image below for the same time as the DNB images displayed above.  An added feature of the GeoColor imagery is the use of the 11-3.9 micron difference (the standard AWIPS fog product) to color low clouds and fog in a pinkish tone to highlight them from other clouds, as seen below.  One characteristic of the imagery that has been noticed during cases of fog is that there may be some information about the thickness and/or density of the fog by how much of the city lights appear through the fog layer, and it will be interesting to examine more DNB imagery in this regard.

GeoColor imagery over the western half of the CONUS at 0945 UTC on 20 December 2013.

Note how in the GeoColor imagery higher clouds appear in white tones, and we can see that high clouds extend across portions of eastern Colorado, covering the lower clouds and fog.  However, going back to the DNB imagery,  the cirrus barely shows in this imagery (as it would with visible imagery in the daytime) and we are therefore able to see the low clouds and fog more clearly.  This example shows how VIIRS and GOES-R could be used in synergy during the GOES-R era.

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One Response to Fog and Low Clouds in Eastern Colorado as seen with GeoColor and Day Night Band NPP VIIRS imagery on 20 Dec 2013

  1. I’ve been looking at DNB (and brightness temperature difference) over the PAC NW the past couple days: Great time of the lunar cycle for imagery !

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