Welcome to the ACTRIS Data Centre node for aerosol remote sensing profiling (ARES)





What ARES provides

The ARES data centre unit provides data curation and data processing service for aerosol remote sensing data coming from lidar and photometer observations. ARES collaborates closely with the ACTRIS Centre for Aerosol Remote Sensing (CARS).

Major objectives also include the development and validation of new synergetic remote sensing algorithms, and the continuous evaluation of the representation of clouds and other atmospheric parameters in climate and weather forecast models.

This node is physically hosted at CNR in Potenza, Italy, where all the data are stored and made available. CNRS is responsible for the combined lidar-photometer processing which is executed in Lille, France.

Contacts: earlinetdb@actris.imaa.cnr.it,  EARLINET Forum



ARES Data Portal

ARES Data Portal

Data Policy

ACTRIS data policy is available here.


ARES Quicklook Interface

ARES Quicklook Interface


ARES Documentation

ACTRIS ARES Data Centre utilizes EARLINET ecosystem to serve official ACTRIS aerosol remote sensing products through the ACTRIS data portal. More info about ACTRIS data can be found from the ACTRIS data management plan.

The EARLINET data portal contains more data than the official ACTRIS data portal, but it may also provide only partially quality controlled data, non-standard metadata schema, experimental products, and so on.

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 through Quality Assurance actions developed and implemented at CARS.

The EARLINET database includes 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. The database includes also volume and particle depolarization ratio profiles at 532 nm (some stations also at 355 nm). In case Raman-lidars are operated, both backscatter and extinction coefficients are provided, together with vertical profiles of lidar ratio.


Data Products Documentation

Following ACTRIS data produtct levels definition, ACTRIS/EARLINET products are:

  • Level 0 data: Raw lidar data in a standardized format compliant to SCC
  • Level 1a data: Pre-processed lidar data
  • Level 1b data: Calibrated lidar signals, namely total attenuated backscatter both at high and low resolution
  • Level 1c data: NRT optical properties retrieved on the base of Level1a and/or Level1b products
  • Level 1d data: Microphysical properties retrieved by combining the lidar level1a data and the sun and moon photometer AERONET level15 data
  • Level 2a data: Optical properties data (correspondingly to Level 1c) compliant with all quality control procedures
  • Level 2b data: Combined lidar+photometer microphysical properties product (correspondingly to level1d data) compliant with all the QC procedures
  • Level 3 data: Advanced data making use of Level 2 aerosol remote sensing data products.

Currently only optical products (Level 1 and Level 2) are available through ARES data portal. Additional Level 3 data are available through zip files.

Level 1 and Level 2 Optical Products

Level 2 data are the optical data that overcome all the data quality controls. Data quality controls are classified into 2 groups Basic quality controls (BQC), checking the presence of technical problems in the data files, and Advanced quality controls (AQC), consisting in checking the data from a physical point of view.

Level 1 data are instead data which fails at least one of the Advanced Quality Control. Each file reports which specific quality control procedure(s) has (have) been failed. Users can make use of such data taking into account the issues highlighted by such failed quality control procedure(s).

More detailed information are reported in the Data File Structure available on this page.

Current quality control procedure is the QCv3.0 and its full documentation is available on this page.

History of the quality control procedures working on the EARLINET database is available on this page.

Documentation of previous quality control procedures is available here.

Level 3 Data

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 obtained by the ACTRIS aerosol remote sensing Data Center node of the CNR in Potenza. This allows the harmonization and reproducibility of the products.

Download the Level 3 Product Catalogue

Download the Level 3 Algorithm Theoretical Basis Document

Download the Level 3 Data products: Part1 - Part2 - Part3

SCC Documentation

The EARLINET Single Calculus Chain (SCC) is a tool for the automatic analysis of aerosol lidar measurements. Its development started in the framework of EARLINET-ASOS (European Aerosol Research Lidar Network – Advanced Sustainable Observation System), it is now a major component of the ACTRIS Aerosol Remote Sensing Node (ARES) responsible for the curation and the processing of the ACTRIS aerosol remote sensing data.

Official documentation can be found at this link.

You can post your questions and comments on the EARLINET forum where SCC problems are discussed and several suggestions can be found. If you don't have account, you can register using your full name and using an institutional email.

More information about the SCC are available here.

GARRLiC Documentation

The GARRLiC algorithm provides micro-physical and optical aerosol properties, inverting simultaneously sun/moon/sky radiometer and lidar ground-based observations. This synergistic approach can provide column-integrated parameters, like the particle volume size distribution, the complex refractive indexes, the spherical fraction, the Aerosol Optical Depth and absorption, the single scattering albedo. The LIDAR vertically resolved measurement allows to retrieve vertically resolved parameters like the abbption, extinction and aerosol concentration profiles.

The science prototype development is as a partnership between the GRASP-SAS company which develops the GRASP (Generalized Retrieval of Atmosphere and Surface Properties) algorithm, and the Laboratoire d’Optique Atmosphérique (LOA) which develops its LIDAR/photometer declination, GARRLiC.

The input data used are, for the photometer part, the AERONET data (Almucantars radiances and Aerosol Optical Depth), and for the LIDAR part, data from ACTRIS/EARLINET stations generated by the SCC.

More information about the GARRLiC project can found here.

More information about the GRASP algorithm can be found here.

Data Submission

WIth the end of the ACTRIS implementation phase, all the ACTRIS data will be directly and automatically transferred by NF to DC, processed and made available.

In the meantime, a tool to upload files, edit categories and download category-files is available at this link.

Since the ARES database is version controlled, once data are submitted they cannot be removed in order to be FAIR versus the users. Therefore, people at the ACTRIS ARES stations are kindly invited to SIMULATE the upload of file(s) on the database through a devoted interface available at this link. This interface requires the credentials you use for the EARLINET database.

Using the interface, the uploader can see how many files, if uploaded on the real ACTRIS/EARLINET database, would be labeled as Level 1 and why. This gives the possibility to check the situation before the uploading of the file on the database.

Additional Services

Further Datasets

Data products are available also as datasets for the users. These can be either collections of data or tailored datasets

Data belonging to a specific category of files (visit this page for more information ), like climatological datasets (i.e. measurements performed following a regular measurement schedule) or related to CALIPSO overpasses over the EARLINET stations, can be extracted through the EARLINET database interface.

In particular, special datasets about COVID 19 measurement campaign, Iceland volcanic eruption in 2010 and SCC operational exercise are currently available.

SCC use by not ACTRIS users

For non ACTRIS/EARLINET lidar stations: the usage/testing of the SCC is possible also for not ACTRIS stations! If you are interested, please, request the access to SCC as ACTRIS DC-ARES service following ACTRIS-IMP instructions at this link and this guide.


THREDDS (Thematic Realtime Environmental Distributed Data Service) is a web server that provides metadata and data access for scientific datasets, using OPeNDAP, OGC WMS and WCS, HTTP, and other remote data access protocols. THREDDS is developed and supported by Unidata, a division of the University Corporation for Atmospheric Research (UCAR), and is sponsored by the National Science Foundation.

ACTRIS DC group proposed to use the standardized THREDDS interfaces as new way of inter-operating between data centre nodes and the ACTRIS data portal. As several standard protocols work out-of-the-box, it improves and make more flexible to serve EARLINET database.

It is available here (login with the same credentials used for the database access).