The European Aerosol Research Lidar Network, EARLINET, was established in 2000 as a research project with the goal of creating a quantitative, comprehensive, and statistically significant database for the horizontal, vertical, and temporal distribution of aerosols on a continental scale. Since then EARLINET has continued to provide the most extensive collection of ground-based data for the aerosol vertical distribution over Europe.
Atmospheric aerosols are considered one of the major uncertainties in climate forcing, and a detailed aerosol characterization is needed in order to understand their role in the atmospheric processes as well as human health and environment. The most significant source of uncertainty is the large variability in space and time. Due to their short lifetime and strong interactions, their global concentrations and properties are poorly known. For these reasons, information on the large-scale three-dimensional aerosol distribution in the atmosphere should be continuously monitored. It is undoubted that information on the vertical distribution is particularly important and that lidar remote sensing is the most appropriate tool for providing this information. Long-term multiwavelength backscatter and extinction coefficient profiles are available from EARLINET through an easily accessible database, covering the European continent.
The dataset is used to validate and improve models that predict the future state of the atmosphere and its dependence on different scenarios describing economic development, including those actions taken to preserve the quality of the environment.
EARLINET will continue to build a quantitative comprehensive statistical database of the horizontal, vertical, and temporal distribution of aerosols on a continental scale. The goal is to provide aerosol data with unbiased sampling, for important selected processes, and air-mass history, together with comprehensive analyses of these data. The objectives will be reached by operating a network distributed over most of Europe, using advanced quantitative laser remote sensing to directly measure the vertical distribution of aerosols, supported by a suite of more conventional observations.
EARLINET measurements must meet stringent stability and absolute accuracy standards to achieve the desired confidence in aerosol radiative forcing needs; thus, the network has developed a rigorous quality assurance program addressing both instrument performance and evaluation of the algorithms. These operational pillars have been developed to ensure instrument standardization and consistent lidar retrievals within the network in a standardized data exchange format. For the full harmonization of data analysis and data traceability, the EARLINET Single Calculus Chain (SCC), a tool for the automatic analysis of lidar measurements has been developed.
A major part of the measurements is performed according to a fixed schedule to provide an unbiased statistically significant data set. Additional measurements are performed to specifically address important processes that are localised either in space or time. Back-trajectories derived from operational weather prediction models are used to characterise the history of the observed air parcels, accounting explicitly for the vertical distribution.
EARLINET is a key component of the ACTRIS infrastructure, which represents a big step towards a better coordination of the atmospheric observations in Europe towards the establishment of the European component of an Integrated Atmospheric Global System as part of GEOSS, the Global Earth Observation System of Systems (GEOSS, 2005). EARLINET is also a contributing network to the GAW Programme.
Currently, EARLINET, in the frame of ACTRIS, is supported by two different EC-projects: ACTRIS-2 (funded by the European Union – Research Infrastructure Action under the H2020 specific programme for “Integrating and opening existing national and regional research infrastructures of European interest” under Grant Agreement n°654109 (1 May 2015 - 1 May 2019) and ACTRIS Preparatory Phase Project (PPP) (a EU Horizon 2020 Coordination and Support Action (grant agreement No 739530, started on 1 January 2017 for a period of 3 years).). The former revolves around the on-going research, coordinating efforts of partner organisations and producing observations and data, while the latter is a project aiming to establish a research infrastructure with its own legal entity and operational structure that will carry on the work done by ACTRIS-2.
In the frame of ACTRIS, the Centre for Aerosol Remote Sensing (CARS) has been created. CARS offers a wide range of services to test and calibrate aerosol high-power aerosol lidars, automatic low-power lidars and ceilometers, automatic sun/sky/polarized/lunar photometer, to assess the whole system’s performance, starting from the characterization and optimization of single components, and to train instrument operators.
For more information about LiCal, visit the CARS webpage.
At present, 33 active stations distributed over Europe are part of the network.
High resolution maps can be downloaded from the download section.