The CNR-IMAA remote sensing aerosol laboratory consists of advanced active and passive instrumentation for the characterization of atmospheric aerosols in terms of optical, microphysical and geometric parameters and for aerosol typing. It represents the state of the art of ground-based remote sensing technology for aerosol research and a reference site for the national, European and international scientific community operating in the sector.
Active since the beginning of the 2000s, data relating to more than 20 years of systematic measurements have been collected. These data are important data for climatological studies, satellite validations, model evaluation, aerosol-cloud interaction, climate change and air quality, but also in support of public bodies, such as Civil Protection and Aviation.
The active instrumentation consists of several lidar systems. In particular, the laboratory is equipped with two multi-wavelength Raman lidar systems, one fixed and one mobile, which represent the state of the art of the Raman lidar technique.
Both systems provide measurements of aerosolized backscattering and depolarization at 1064, 532 and 355 nm and extinction at 532 and 355 nm, with high temporal and spatial resolutions over a wide vertical range starting from 200 m. The fixed lidar also provides water vapor mixing ratio measurements and systematic measurements for ACTRIS (Aerosol, Clouds and Trace Gases Research Infrastructure, https://www.actris.eu/) /EARLINET(European Aerosol Research LIdar NETwork, https://www.earlinet.org) ., whereas the mobile lidar is more compact to be easily transported and used in field measurement campaigns.
The aerosol remote sensing component also includes a lidar laboratory and an optical laboratory.
The lidar laboratory allows setting up different lidar configurations in a modular way: fluorescence, rotational for temperature measurements, HSRL, and multi-wavelength for aerosols, water vapor, both vertically and at different observation angles.
The optical laboratory is equipped for characterization of optical components and laser sources typically used in high power lidar systems.
These four complex instruments are also an important component of the European research infrastructure ACTRIS, as the CNR-IMAA is one of the units of the Central Facility CARS (Centre for Aerosol Remote Sensing), and provides access for test and calibration services both at the observatory on-site through direct intercomparison campaigns with the mobile lidar system. The fixed and mobile lidar systems are reference systems for ACTRIS.
There are also two other lidar systems: a very compact scanning Raman lidar system operating only in the UV, capable of providing backscattering, extinction and aerosol depolarization measurements at 355nm, and MUSA, a system, previously reference for ACTRIS/EARLINET, capable of providing backscattering measurements at 1064, 532 and 355 nm, extinction at 532 and 355 nm and depolarization at 532 nm.
As remote sensing instrumentation for the study of aerosols, there is also an automatic sun/sky/lunar photometer (Cimel 318T), equipped with 9 spectral filters from 340 to 1640 nm. It represents the state of the art of photometric measurement techniques and provides measurements of aerosol properties both directly (e.g. AOD, spectral and polarized radiance) and indirectly (e.g. size distribution, refractive index, single scattering albedo, spherical fraction, properties scattering). This system allows measurements not only in daytime conditions, but also at night with sufficient lunar/stellar illumination. The system is part of the AERONET network (AErosol RObotic NETwork, https://aeronet.gsfc.nasa.gov/) and ACTRIS infrastructure. In addition to this photometer, there is an additional photometer, also part of ACTRIS/AERONET, which although it is a previous model (exclusively solar), allows to limit the lack of observations in the periods relating to the calibration phase of the main photometer and the use in measurement campaigns on other sites.
