Report on the EARLINET database product format

EARLINET, the European Aerosol Research Lidar Network, has been operated in Europe since the year 2000 and provides the scientific community with the most complete database of vertically resolved aerosol optical parameters across Europe (Pappalardo et al., 2014, www.earlinet.org). The EARLINET data can be used for several purposes including model evaluation and assimilation, full exploitation of satellite data, the study of aerosol long-range transport mechanisms, and the monitoring of special events like volcanic eruptions, large forest fires or dust outbreaks. The EARLINET database, also, takes advantage from the centralized data processing through the common standardized automatic analysis software developed within EARLINET, the Single Calculus Chain (SCC) (D'Amico et al., 2015). It is also possible the submission of data analyzed by using specific Quality Assured (QA) and documented software. The usage of the SCC assures the usage of QA retrieval algorithms and the full traceability of all EARLINET products. A further important pillar of EARLINET is the cooperation with other observing networks and European and international programs. Synergies with AERONET (AErosol RObotic NETwork), using the collocation of most of the EARLINET stations with AERONET, have been exploited for the retrieval of aerosol microphysical properties (Müller et al., 2003; Ansmann et al., 2012; Wagner et al., 2013; Lopatin et al., 2013; Granados-Muñoz et al., 2014; Mamouri and Ansmann, 2014). EARLINET is contributing to GALION, the GAW Aerosol Observation Lidar network (http://alg.umbc.edu/galion/). In this report we describe the EARLINET data product format and its CF (Climate and Forecast) compliance. All the data products are in netCDF format which is commonly and widely used within the environment and climate domain. The CF compliance is envisaged for all the network products in order to foster a wide use of the EARLINET data within the climate modeling community. The conventions for CF metadata are designed to promote the processing and sharing of files created with the NetCDF API. The CF conventions are increasingly gaining acceptance and have been adopted by a number of projects and groups as a primary standard. The conventions define metadata that provide a definitive description of what the data in each variable represents, and the spatial and temporal properties of the data. This enables users of data from different sources to decide which quantities are comparable, and facilitates building applications with powerful extraction, regridding, and display capabilities.