Dust Storms

Aerosol Optical Depth (AOD) (or Aerosol Optical Thickness) indicates the level at which particles in the air (aerosols) prevent light from traveling through the atmosphere. Aerosols scatter and absorb incoming sunlight, which reduces visibility. From an observer on the ground, an AOD of less than 0.1 is “clean” - characteristic of clear blue sky, bright sun and maximum visibility. As AOD increases to 0.5, 1.0, and greater than 3.0, aerosols become so dense that sun is obscured. Sources of aerosols include pollution from factories, smoke from fires, dust from dust storms, sea salt, and volcanic ash and smog. Aerosols compromise human health when inhaled by people, particularly those with asthma or other respiratory illnesses. Aerosols also have an effect on the weather and climate by cooling or warming the earth, helping or preventing clouds from forming. Since aerosols are difficult to identify when they occur over different types of land surfaces and ocean surfaces, Worldview provides several different types of imagery layers to assist in the identification.

MODIS and VIIRS Corrected Reflectance imagery are available only as near real-time imagery. The imagery can be visualized in Worldview and Global Imagery Browse Services (GIBS). More:

Information on MODIS Corrected Reflectance Imagery layers including

• Corrected Reflectance True Color (Bands 1-4-3),
• Corrected Reflectance (Bands 3-6-7)
• Corrected Reflectance (Bands 7-2-1)

Information on VIIRS Corrected Reflectance Imagery layers including

• Corrected Reflectance True Color (Bands I1-M4-M3),
• Corrected Reflectance (Bands M3-I3-M11)
• Corrected Reflectance (Bands M11-I2-I1)

Browse Corrected Reflectance imagery in Worldview

For more on the difference between Corrected Reflectance and Surface Reflectance Imagery

In comparison with the MODIS Corrected Reflectance product, the MODIS Land Atmospherically Corrected Surface Reflectance product (MOD09) is a more complete atmospheric correction algorithm that includes aerosol correction, and is designed to derive land surface properties.