Small area of fog only visible on VIIRS DNB Nighttime Microphysics channel

Starting around 07Z last night, we noticed a station in the far northeast corner of Colorado reporting some reduction in visibility, with no other stations nearby reporting any reduction.  We couldn’t see any indication in the 11u-3.9u IR satellite imagery.  Once the VIIRS DNB imagery came in of the 09:04UTC imagery set, it was definitely evident in the Nighttime Microphysics channel, slightly in the Dust RGB channel, but not at all in the other DNB channels.  Good to know the sensor was reporting correctly!

20141026_0904_sport_viirs_frontrange_dnbrefrgb 20141026_0904_sport_viirs_frontrange_11um 20141026_0904_sport_viirs_frontrange_dust 20141026_0904_sport_viirs_frontrange_ntmicro

Seen above, top to bottom:  VIIRS DNB Reflectance RGB, IR Longwave, Dust RGB, Nighttime Microphysics imagery.  The latter definitely shows the small patch of fog clearly with the whiter (lower) clouds.

2 thoughts on “Small area of fog only visible on VIIRS DNB Nighttime Microphysics channel

  1. BOU

    Well done in the analysis of the imagery and recognizing the small scale fog feature in the Nighttime Microphysics Imagery from S-NPP VIIRS. Looking at the 11-3.9u difference from MODIS did show a large number of areas that could be fog; however the VIIRS 11-3.9u did well to highlight this fog feature. The NtMicro RGB helps to more clearly depict the microphysical and thermal features of the clouds to pinpoint what is fog and what are low to high clouds. The Aqua-MODIS NtMicro RGB also did well in showing the fog at this time, similar to VIIRS. Just a small side note that the original title of this post seems to combine the VIIRS Day-Night Band (DNB) and the NtMicro RGB products, and I wanted to note that these are two separate products as you have shown in the images. The DNB can also indicate fog and/or low clouds when city lights appear diffuse compared to clear sky conditions or when sufficient moonlight is reflected from these cloud features.

    Thank you for your valuable contribution to the community on the application of RGB imagery from VIIRS.

    Kevin Fuell

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