Aerosols

The main asset of the CALIPSO is that based on Lidar profiles, it can detect aerosols when the classical passive imagery (except the polarization) is inefficient: aerosols over lands and reflecting clouds, and aerosols under semi-transparent cirrus

The restitution accuracy of aerosol optical thickness is about 30% with the Lidar alone. The association of the Lidar and the oxygen spectrometer improves this figure for the heavy aerosol contents and fulfils the requirements of direct radiative effect calculations (cf curve NRC, 1996).

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

In this context, CALIPSO supplies:

• the aerosol vertical distribution,
• a size classification based on retrodiffusion in a two-channel measurement,
• the aerosol optical thickness,
• the simple diffusion albedo,
• the source intensity for the transport models.