The OMI instrument, on board of Aura platform can distinguish between aerosol types, such as smoke, dust, and sulphates, and measures cloud pressure and coverage, which provide data to derive tropospheric ozone. OMI continues the TOMS record for total ozone and other atmospheric parameters related to ozone chemistry, aerosols and climate. OMI measurements are highly synergistic with the other instruments on the Aura satellite.
The TOMS aerosol index is a measure of how much the wavelength dependence of backscattered UV radiation from an atmosphere containing aerosols (Mie scattering, Rayleigh scattering, and absorption) differs from that of a pure molecular atmosphere (pure Rayleigh scattering). Quantitatively, the aerosol index AI is defined to be:
is the measured 360 nm EP-TOMS radiance
is the calculated 360 nm EP-TOMS radiance for a Rayleigh atmosphere.
Under most conditions, the AI is positive for absorbing aerosols and negative for nonabsorbing aerosols (pure scattering).