November 19, 2023

Aerosols

The main asset of the CALIPSO mission is that based on lidar profiles, it can detect aerosols when traditional passive imagery (except the polarization) is ineffective, i.e. aerosols over land and reflecting clouds, and aerosols under semi-transparent cirrus clouds.

The restitution accuracy of aerosol optical thickness is about 30% with the lidar alone. The combination of the lidar and the oxygen spectrometer improves this percentage for high aerosol contents and fulfils the requirements for direct radiative effect calculations (see NRC curve, 1996).

Thanks to the combination of aerosol properties derived from CALIPSO and radiation fluxes and atmosphere profiles derived from EOS, aerosol direct radiative impact and the parameters which control it are measured.

In this context, CALIPSO provides:

  • the aerosol vertical distribution
  • a size classification based on backscattering in a two-channel measurement
  • the aerosol optical thickness
  • the single-scattering albedo
  • the source intensity for transport models