03 Jan Is it Cloud or is it Dust?
A large dust cloud hangs over the Atlantic along the northwestern coast of Africa in this color-enhanced image captured by the NOAA/NASA Suomi NPP satellite’s Visible Infrared Imaging Radiometer Suite (VIIRS) instrument on December 27, 2016.
The bright colors shown here are the result of a “dust enhancement” — an experimental data product created by scientists at the European Organisation for the Exploitation of Meteorological Satellites (aka: EUMETSAT). Based on infrared channel data, this RGB (red-green-blue) enhancement was created to help analysts monitor the evolution of dust storms. According to EUMETSAT, monitoring of dust in the atmosphere 24 hours a day can be a challenge because the appearance of dust in satellite imagery changes drastically from day to night. Incorporating VIIRS day/night band into the mix of channels used to produce these images makes it easier.
So where is the dust visible in this image? Well, it’s not represented by the orange/brown color–that’s atmospheric moisture. Rather, the dust appears as magenta or pink. The other colors denote the following: Reds mark thick cirrus clouds, dark blues are thin cirrus clouds, and the other shades of blue indicate the surface (land and water) of the Earth. The bright yellow is the hot surface of the Sahara.
Link to full article: https://www.nnvl.noaa.gov/MediaDetail2.php?MediaID=1982&MediaTypeID=1