Multiwavelength aerosol lidars at Maïdo Observatory

Since 2012, 3 lidars from the Atmospheric Physics Observatory of La Réunion (OPAR) have been performing aerosol profile measurements at the Maïdo observatory site, located at 2160 meters to the west of the island of La Réunion. These profiles are obtained at several wavelengths, 355nm and 532nm, and there are also depolarized channels at 532nm.

The data from these 3 lidars are processed in two stages: initially, the data are manually cleaned of disturbed profiles, either by atmospheric effects, such as the passage of clouds, or by electronic effects like noise. They are then summed over the night. This is the L1b level, and the data are available in the Matlab format (.mat). Subsequently, the data are processed to convert from a profile of received photon number to a profile of aerosol extinction and scattering. The methodology used is based on the Klett calculation at one wavelength. This is the L2b level, and the data are available in the NetCDF format (.nc) with the NDACC convention in the choice of variable names. Therefore, the data are distributed across 6 directories, 2 levels of processing for each lidar.

The raw data from the instrument (called L0) are in a proprietary format, the Licel format, and are not accessible in open access, only via FTP with restricted access.