The ARCADE project: Characterization of aerosol attenuation properties in the near UV for astroparticle experiments

Cosmic rays experiments based on UV light detectors need a precise and continuous measurement of the atmospheric properties in order to correctly retrieve parameters related to the energy and composition of primaries from the observed UV light profiles. Aerosols play a critical role, being the most variable component of the atmosphere. LIDARs and distant laser facilities for side-scattering measurements are typically used to monitor the aerosol attenuation during data acquisition. The ARCADE project, taking place in Colorado, will measure the aerosol attenuation properties of the atmosphere in the near UV using for the first time a steerable elastic and Raman LIDAR and side-scattering techniques on the same air mass and at the same time. The goals of the project are: the comparison of different hardware and analysis techniques to highlight their points of strength, limitations and systematics; the development of models to describe the stratification of aerosols in the areas of measurement, and their dependence on temperature, wind, precipitation, and humidity; the study of the cloud cover and the measurement of the cloud optical depth. A detailed hardware description, simulations and the first tests of the instrumentation are presented.