European validation of SAGE II aerosol profiles

A SAGE II validation program has been performed in Europe using ground-based lidars and balloon-borne polarimetric and photographic experiments. Between the tropopause height and about 23 km, good agreement is found between the SAGE II 1.02-μm extinction profiles and the lidar profiles, using for the conversion of backscattering into extinction an aerosol model consistent with the SAGE II spectral extinction. The extinction profiles deduced from the limb photographs at 0.44 and 0.375 μm present a good agreement with the SAGE II profiles at 0.453 and 0.385 μm, respectively. The size distribution retrieved from the near-infrared polarimetric observations leads to a spectral variation of the extinction in good agreement with SAGE II data in the same altitude range. Above 23–25 km the observations are scarce and the data of poorer quality because of the low aerosol content. The 1.02-μm extinction profiles seem to agree with the ruby lidar and the limb photograph profiles. But any conclusion concerning the short-wavelength profiles and the size distribution at these high altitudes would be risky.