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Aura Science

Combined use of A-train data for improved aerosol characterization

Aura-OMI near-UV observations are sensitive to aerosol absorption. Information on aerosol layer height is needed to retrieve single scattering albedo, the ratio of scattering efficiency to total light extinction.

A Single-Scattering Albedo (SSA) value of 1.0 means that an aerosol scatters light, but does not absorb it. Clouds have an SSA near 1 at most wavelengths. Values less than 1.0 mean that light is being absorbed. Both dust and smoke absorb light, particularly at ultraviolet wavelengths.

Aura and CALIPSO

OMI and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) observations are a few minutes apart. The CALIPSO satellite provides new insight into the role that clouds and atmospheric aerosols (airborne particles) play in regulating Earth's weather, climate, and air quality. CALIPSO combines an active lidar instrument with passive infrared and visible imagers to probe the vertical structure and properties of thin clouds and aerosols over the globe.


These figures show a typical cross section through a Sarahan dust cloud. The red line indicates the CALIPSO orbital track. The CALIPSO lidar backscatter measurements show an extensive dust layer occurring at altitudes between about 3 and 6 km. Clouds (white color) are also present above and below this dust plume. The red line in the figure on the left indicates the CALIPSO orbital track.

OMI retrievals of SSA (below) are improved by using estimates of the aerosol height from CALIPSO. Red values of SSA show the regions where smoke and dust absorb sunlight.

Caliop-measured aerosol layer height

Caliop-measured aerosol layer height

>OMI-retrieved single Scattering Albedo

OMI-retrieved single Scattering Albedo

Related Feature:

Aerosol feature

Aerosols: Tiny Particles, Big Impact

Learn all about aerosols in this Earth Observatory article

Courtesy Omar Torres Hampton Univ.