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VIIRS SnowCloud Discriminator for Sea Ice Monitoring

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The VIIRS SnowCloud Discriminator (VSCD) combines information from 10 different bands on VIIRS (6 during the day and 4 at night) to help distinguish clouds from snow and ice. Unlike other RGBs for snow and cloud discrimination, which only work during the day, the Snow/ Cloud Discriminator utilizes the Day/Night Band (DNB) so it works around the clock. This is particularly useful during those long winter nights. GINA provides real time access to this product at http://hippy.gina.alaska.edu/distro/cira/

In the VSCD, low clouds appear yellow, mid clouds orange, and high clouds magenta making them easier to distinguish from the white ice or snow. This is a big advantage over single bands like the DayNightBand below that shows only grey shades.

This DayNight Band (DNB) image (above) at 1738 UTC 25 Oct 2021 shows the Arctic ice pack when skies were relatively clear, however some areas of the ice appear fuzzy while others are more defined.
The VSCD (above) shows that the reason for the “fuzzy” appearance in some areas is a thin layer of low clouds (yellow). The leads and polynyas (cracks and open areas) in the ice are still very visible through the low clouds.
The DayLandCloud RGB (above) at 1721 UTC 26 Oct 2021 can be helpful for identifying sea ice during the summer months, but because it is a daytime only product it has limited usefulness during the darker months of the year.
The SnowCloud Discriminator (above) for the same time as the DayLandCloud RGB uses the DayNightBand and Infrared channels to provide imagery whether or not sunlight is available.
And since polar satellites frequently pass over the far northern latitudes there are many images to compare or animate to determine ice motion.

The VIIRS SnowCloud Discriminator was developed by Dr. Steve Miller and Dr. Curtis Seaman at the Cooperative Institute for Research in the Atmosphere (CIRA). More information on this product can be found here: https://rammb2.cira.colostate.edu/wp-content/uploads/2020/01/VIIRS_Cloud_Snow_Discriminator_Quick_Guide_02152018-1.pdf