The EARLINET database represents a comprehensive, quantitative, and statistically significant collection of data for the aerosol distribution on European scale. The data quality of the database is assured by harmonized quality assurance and quality control actions. It is an important source of data to contribute to the quantification of anthropogenic and biogenic emissions and concentrations of aerosol, quantification of their budgets, radiative properties and prediction of future trends. EARLINET database can improve the understanding of physical and chemical processes related to the aerosols, their long-range transport and deposition, and their interaction with clouds.
The EARLINET database is a publicly available system that allows scientists to search, download and visualize aerosol lidar data from the EARLINET network.
The EARLINET database is handled by ACTRIS ARES (Aerosol REmote Sensing) DC unit. ACTRIS ARES provides data curation, data processing, data provision and access services for ACTRIS/EARLINET aerosol remote sensing data coming from lidar data even combined with photometer observations.
The database contains data resulting from observations performed at long-term operating lidar stations (like the ACTRIS ones), from not permanent lidar stations performing measurements in occasion of some specific studies/campaigns (like the ones close to Etna) and can host data coming from mobile stations (transportable lidars operated in different locations).
Data can be accessed through the visual interface and the REST API. The access is open and credential-free.
The EARLINET database includes the following products:
The aerosol backscatter coefficient profiles (as a function of height above mean sea level), together with their errors, mainly at one or more out of the following wavelengths: 355 nm, 532 nm and 1064 nm, but a subset of measurements is related also to different wavelengths. The database includes also volume and particle depolarization ratio profiles at 532 nm (for some stations also at 355 and/or 1064 nm). In case Raman-lidars are operated, both backscatter and extinction coefficients are provided, together with vertical profiles of lidar ratio. The database provides also the aerosol layer height (top of the atmospheric boundary layer) and the mixing layer height (top of convective boundary layer). All the data are stored in CF-compliant Netcdf-Format.
Currently, most of the optical product's profiles are generated by the EARLINET Lidar Data Analyser (ELDA) module of the Single Calculus Chain (SCC), which is the standard EARLINET processing suite to perform automatic and quality checked analysis of raw lidar data and it is mandatory for ACTRIS stations.
The CloudScreen products are generated by the SCC. The CloudScreen products contain a 2-dimensional grid (x axis: time y axis: altitude) with the same resolution as the corresponding HiRELPP product, in which each pixel is flagged as cloud free or cloud contaminated. This information is used by other SCC modules for the automatic removal of the cloud contribution within the aerosol optical property products. More information can be found here.
The ELDEC products are generated by the SCC and provide the calibration parameter following the quality assurance procedures defined within ACTRIS CARS (Centre for Aerosol Remote Sensing), which is used to provide calibrated volume and particle depolarization ratio profiles. More information can be found here.
The ELIC products are generated by the SCC. They contain the calibrated high- and low-resolution pre-processed products (HiRELPP end ELPP products respectively), which is done by using the same calibration constant computed by ELDA during the retrieval of low-resolution optical aerosol properties (elastic/Raman bacskcatter calibration). More information can be found here.
The ELPP products are generated by the SCC. They contain the lidar pre-processed data, which is obtained after implementing all the needed corrections and transformations to be applied to the raw data before they can be used to derive the optical products at low temporal/spatial resolution. In the ELPP products, the correction of some instrumental effects (like for example, dead-time correction, trigger-delay correction, overlap correction, atmospheric and electronic background subtraction, low- and high-range automatic signal glueing) are implemented following the recommendations provided by the EARLINET quality assurance program. More information can be found here.
The HiRELPP products are generated by the SCC. As in the ELPP products, the HiRELPP products contain the lidar pre-processed data after the implementation of all the needed corrections. All the operations implemented in HiRELPP are designed to preserve both the vertical and time resolution as high as possible. More information can be found here.
GARRLiC is a unified algorithm that combines primary data obtained from sun/sky photometer (spectral Extinction AOD and spectral radiance) and elastic attenuated backscatter lidar profiles at one or several wavelengths, typically at 355, 532 and 1064 nm. Its objective is to produce as much as possible aerosol optical and micro-physical properties, such as the aerosol volume size distribution, the complex refractive index, the fraction of spherical particles and the height-resolved aerosol concentration. More information can be found here.
Data included in the database are labelled as Level 1 and Level 2.
Data are labelled as Level 1 if the files have overcome Basic Quality Controls (BQC), consisting in checking the presence of technical problems in the data files. The Basic Quality Controls are applied to all the products that are available in the database.
Data are labelled as Level 2 if they have overcome Advanced Quality Controls (AQC), consisting in checking the data from a physical point of view. The Advanced Quality Controls are only applied to the optical data. A detailed description of the quality control tests can be found in the Quality Control web page.
Specific datasets are related to collection of measurements for case studies or campaigns (like the ones related to EMORAL system data collected during the 2024 CINDI3 campaign) or to advanced products related to special events (like the one related to the Eyjafjallajökull volcano eruption in 2010).
They can be found at the Special datasets page.
Annual datasets are released by ACTRIS ARES every year for each station and each optical property profile. A collection is provided at station granularity including all the optical products together. Finally, an overall dataset collects all the aerosol optical property profiles collected in the year at ACTRIS/EARLINET stations. They can be found at the Annual datasets page.
Since 28 March 2019, ACTRIS/EARLINET Level 3 Data products are also available. Level 3 data are the climatological products obtained from the fully quality controlled (Level 2) data for providing useful aggregated information to the users. The Level 3 data are centrally processed by ACTRIS ARES. This allows the harmonization and reproducibility of the products. The detailed documentation and the data products can be found at the Level 3 data webpage.
The optical data products in the database can be associated to the following specific datasets: