VIIRS Aerosol Detection
Frequently Asked Questions about the VIIRS Aerosol Detection Product
1) What is this product?
This product outputs six different possibilites of aerosol or no aerosol in the atmosphere. The various possible categories are volcanic ash, clouds, dust, smoke, none/unknown/clear, and snow/ice. This product is useful not only to identify the presence of aerosols in the atmosphere, but also in identifying the type of aerosol, especially differentiating between smoke and dust. This information can assist with forecasting dust storms and issuing dust storm warnings, identifying the movement of volcanic ash, recognizing smoke from fires that may not yet be large enough for the VIIRS Active Fires Product to detect, and being aware of decreased air quality.
2) How often do I receive this data?
The S-NPP satellite is part of the Afternoon Train (A-Train) of satellites. It crosses the equator at ~1:30am and ~1:30pm local time every day. However, this product is only produced during daytime hours.
3) How do I display this product in AWIPS-II?
4) How do I interpret the color maps associated with this product?
5) What should I use in conjunction with this product to produce a better forecast?
Geostationary satellite imagery, including the GOES-R Aerosol Detection product. Also, the VIIRS Aerosol Optical Depth Product.
6) How is this product created?
Image based aerosol detection always involves assumptions of the radiometric characteristics of aerosol, clear and cloudy scenes. The surface conditions also influence the separation of aerosol pixels from those with clear-sky or cloud. The product algorithm currently uses spectral and spatial tests to identify pixels with smoke or dust in the daytime. The algorithm also treats the detection differently for water and land. 1
Techniques for the remote sensing of aerosols using solar and thermal measurements from satellites have been developed for several instruments, including AVHRR and MODIS. Fundamentally, these methods are based on the radiative signatures of aerosols. The problem of accurate detection and classification is compounded by the fact that the physical characteristics of aerosols (e.g. particle size distribution, concentration, chemical composition, location in the atmosphere) change as the aerosol layer develops and dissipates. These physical changes are capable of affecting the radiative characteristics of the original aerosol and our capability to detect them from satellite observations. In addition to being present at the source region, aerosols are transported by winds to other regions of the globe.1
1NOAA/NESDIS/STAR. NOAA NESDIS Center for Satellite Applications and Research Algorithm Theoretical Basis Document: JPSS Suspened Matter (Aerosol Detection) Product. v1.0, December 9 2015.