EARLINET Single Calculus Chain - overview on methodology and strategy

Abstract. In this paper we describe the EARLINET Single Calculus Chain (SCC), a tool for the automatic analysis of lidar measurements. The development of this tool started in the framework of EARLINET-ASOS (European Aerosol Research Lidar Network – Advanced Sustainable Observation System); it was extended within ACTRIS (Aerosol, Clouds and Trace gases Research InfraStructure Network), and it is continuing within ACTRIS-2. The main idea was to develop a data processing chain that allows all EARLINET stations to retrieve, in a fully automatic way, the aerosol backscatter and extinction profiles starting from the raw lidar data of the lidar systems they operate. The calculus subsystem of the SCC is composed of two modules: a pre-processor module which handles the raw lidar data and corrects them for instrumental effects and an optical processing module for the retrieval of aerosol optical products from the pre-processed data. All input parameters needed to perform the lidar analysis are stored in a database to keep track of all changes which may occur for any EARLINET lidar system over the time. The two calculus modules are coordinated and synchronized by an additional module (daemon) which makes the whole analysis process fully automatic. The end user can interact with the SCC via a user-friendly web interface. All SCC modules are developed using open-source and freely available software packages. The final products retrieved by the SCC fulfill all requirements of the EARLINET quality assurance programs on both instrumental and algorithm levels. Moreover, the manpower needed to provide aerosol optical products is greatly reduced and thus the near-real-time availability of lidar data is improved. The high-quality of the SCC products is proven by the good agreement between the SCC analysis, and the corresponding independent manual retrievals. Finally, the ability of the SCC to provide high-quality aerosol optical products is demonstrated for an EARLINET intense observation period.

[1]  Albert Ansmann,et al.  Multiyear aerosol observations with dual‐wavelength Raman lidar in the framework of EARLINET , 2004 .

[2]  A. Ansmann,et al.  Microphysical particle parameters from extinction and backscatter lidar data by inversion with regularization: simulation. , 1999, Applied optics.

[3]  Diofantos G. Hadjimitsis,et al.  EARLINET: potential operationality of a research network , 2015 .

[4]  Lars Schneidenbach,et al.  Microphysical particle properties derived from inversion algorithms developed in the framework of EARLINET , 2015 .

[5]  A. Ansmann,et al.  Measurement of atmospheric aerosol extinction profiles with a Raman lidar. , 1990, Optics letters.

[6]  F. G. Fernald.  Analysis of atmospheric lidar observations: some comments. , 1984, Applied optics.

[7]  J. Klett.  Lidar inversion with variable backscatter/extinction ratios. , 1985, Applied optics.

[8]  Albert Ansmann,et al.  Unexpectedly high aerosol load in the free troposphere over central Europe in spring/summer 2003 , 2003 .

[9]  Omar Torres,et al.  PARAGON: An Integrated Approach for Characterizing Aerosol Climate Impacts and Environmental Interactions , 2004 .

[10]  Anatoli Chaikovsky,et al.  Lidar network CIS-LiNet for monitoring aerosol and ozone in CIS regions , 2006, Atmospheric and Ocean Optics.

[11]  V. Freudenthaler,et al.  EARLINET instrument intercomparison campaigns: overview on strategy and results , 2015 .

[12]  J. Ackermann.  The Extinction-to-Backscatter Ratio of Tropospheric Aerosol: A Numerical Study , 1998 .

[13]  C. Böckmann.  Hybrid regularization method for the ill-posed inversion of multiwavelength lidar data in the retrieval of aerosol size distributions. , 2001, Applied optics.

[14]  A. Ansmann,et al.  Aerosol lidar intercomparison in the framework of the EARLINET project. 2. Aerosol backscatter algorithms. , 2004, Applied optics.

[15]  Vincenzo Cuomo,et al.  CIAO: the CNR-IMAA advanced observatory for atmospheric research , 2010 .

[16]  M. Wendisch,et al.  Optical and microphysical characterization of biomass‐ burning and industrial‐pollution aerosols from‐ multiwavelength lidar and aircraft measurements , 2002 .

[17]  A. Ansmann,et al.  Aerosol lidar intercomparison in the framework of the EARLINET project. 3. Raman lidar algorithm for aerosol extinction, backscatter, and lidar ratio. , 2004, Applied optics.

[18]  J. Klett.  Stable analytical inversion solution for processing lidar returns. , 1981, Applied optics.

[19]  A. Smirnov,et al.  AERONET-a federated instrument network and data archive for aerosol Characterization , 1998 .

[20]  Dietrich Althausen,et al.  PollyNET: a network of multiwavelength polarization Raman lidars , 2013, Remote Sensing.

[21]  A. Ansmann,et al.  Microphysical particle parameters from extinction and backscatter lidar data by inversion with regularization: theory. , 1999, Applied optics.

[22]  V. Berardi,et al.  Two wavelength lidar analysis of stratospheric aerosol size distribution , 1995 .

[23]  Ina Mattis,et al.  EARLINET Single Calculus Chain – technical – Part 1: Pre-processing of raw lidar data , 2015 .

[24]  A. Ansmann,et al.  Combined raman elastic-backscatter LIDAR for vertical profiling of moisture, aerosol extinction, backscatter, and LIDAR ratio , 1992 .

[25]  V. Freudenthaler,et al.  Aerosol lidar intercomparison in the framework of the EARLINET project. 1. Instruments. , 2004 .

[26]  F. A. Johnson,et al.  Dead-Time Corrections to Photon Counting Distributions , 1966 .

[27]  A. Stohl,et al.  Raman lidar observations of aged Siberian and Canadian forest fire smoke in the free troposphere over Germany in 2003 : Microphysical particle characterization , 2005 .

[28]  V. Freudenthaler,et al.  EARLINET: towards an advanced sustainable European aerosol lidar network , 2014 .

[29]  S. H. Melfi,et al.  Raman lidar system for the measurement of water vapor and aerosols in the Earth's atmosphere. , 1992, Applied optics.

[30]  L. Alados-Arboledas,et al.  Assimilation of lidar signals: application to aerosol forecasting in the western Mediterranean basin , 2014 .

[31]  Detlef Müller,et al.  Systematic error of lidar profiles caused by a polarization-dependent receiver transmission: quantification and error correction scheme. , 2009, Applied optics.

[32]  Ina Mattis,et al.  EARLINET Single Calculus Chain – technical – Part 2: Calculation of optical products , 2016 .

[33]  Doina Nicolae,et al.  Assessment of aerosol's mass concentrations from measured linear particle depolarization ratio (vertically resolved) and simulations , 2013 .

[34]  Multiwavelength lidar for ozone measurements in the troposphere and the lower stratosphere. , 1990, Applied optics.

[35]  D. Winker,et al.  Initial performance assessment of CALIOP , 2007 .

[36]  Comparison of Aerosol Backscatter and Extinction Profiles Based on the Earlinet Database and the Single Calculus Chain for Thessaloniki Greece (2001–2014) , 2016 .