LIDAR 1200 - La Réunion Maïdo station - Level 2B Aerosol

The LIDAR 1200 is a Rayleigh Raman lidar able to measure vertical profiles of temperature between 30 and 100 km asl and water vapor ratio from the ground up to 18 km. Vertical profiles of aerosol light extinction and backscattering can also be retrieved from the raw signals, as this instrument provides Rayleigh-Mie scattering at 355 nm and Raman N2 scattering at 387 nm. This instrument has been operating at the Maïdo facility since 2012 and produces data since 2013.

The Observatory of Atmospheric Physics of La Réunion (OPAR), located on Réunion Island near Madagascar (21.079°S, 55.383°E), is currently equipped with more than 50 instruments distributed over three different sites: two historical coastal sites in the north, and a high-altitude site (Maïdo observatory, 2160 m asl), which now houses more than two-thirds of these instruments. OPAR is part of many international networks, including GAW (Global Atmospheric Watch), NDACC (Network for the Detection of Atmospheric Composition Change), SHADOZ (Southern Hemisphere Additional OZonesondes), and AERONET (Aerosol Robotic Network). Additionally, it is a part of the European research infrastructures ACTRIS (Aerosol, Clouds, and Trace Gases Research Infrastructure) and ICOS (Integrated Carbon Observing System).

The data is 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. 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.

Time series of the Lidar1200 level 2B aerosol profile product correspond to the second stage of the process. The final file is in NetCDF format, with the NDACC methodology.