About 

The VIIRS Aerosol Products include 3 products: Aerosol Optical Depth/Thickness (AOD/AOT), Aerosol Detection (ADP), and Volcanic Ash.

AOD is a measure of extinction of radiation by aerosols due to absorption and scattering. It depends on the chemical composition and size of aerosol particles, and thus varies with the wavelengths of radiation. It also depends on the amount of aerosol in the atmosphere, and as such it is also a measure of aerosol loading. The primary product is AOD at 550nm (AOD550). Its value is proportional to the amount of aerosol in a cloud-free, vertical column of the atmosphere over a given satellite pixel. The AOD algorithm determines it by comparing the reflected radiation observed by the satellite instrument in selected spectral bands within 0.412 to 2.25 micrometers with those calculated for increasing values of AOD in a radiative transfer model. Over water, the Aerosol Particle Size Parameter (APSP) is also derived from this algorithm, reported as the Ångström Exponent. The larger the exponent, the smaller the particles.

The ADP algorithm uses spectral and spatial threshold tests to identify pixels with smoke or dust aerosols. Because the presence of smoke and dust are independently derived, a given pixel can be identified with both dust and smoke. The algorithm utilizes fourteen different spectral bands ranging from 0.412 to 12 microns.

The Volcanic Ash algorithm determines the location, height and mass loading properties for satellite pixels potentially containing volcanic ash. The EDR contains two images with pixel values identifying volcanic ash cloud height and volcanic ash mass loading. The algorithm utilizes the M14 (8.55 microns), M15 (10.763 microns), and M16 (12.013 microns) spectral bands.

Limitations

Temporal Resolution: For a CONUS location, daylight observations occur every 22 hours on average. The next pass occurs at night, approximately 10 hours later. There is a 50-minute gap between the midday NOAA-20 and S-NPP viewings.

Cloud Coverage: Clouds block aerosol algorithm retrievals, so there is no data for cloud-covered areas.

AWIPS 

Location: N/A

Color Maps: Grid/gridded_data

Sampling: N/A

Quality Flags: QCA

Technique: Aerosols released into the atmosphere due to natural and anthropogenic activities lead to deteriorated air quality and affect Earth’s climate. It is important to regularly monitor the global aerosol distributions and study how they are changing, especially for those aerosols with large spatial and temporal variability, such as smoke, sand storms, and dust.

AOD is useful for identifying and tracking areas of high particulate concentrations that correspond to an air quality event, such as a wildfire, dust storm, or haze episode. ADP is specialized for identifying smoke and dust with 70-80% accuracy. Volcanic ash products are also useful for enhancing ash dispersion and trajectory prediction models.