Status: this preprint is currently under review for the journal AMT.
DeLiAn – a growing collection of depolarization ratio, lidar ratio and Ångström exponent for different aerosol types and mixtures from ground-based lidar observations
Athena Augusta Floutsi1,Holger Baars1,Ronny Engelmann1,Dietrich Althausen1,Albert Ansmann1,Stephanie Bohlmann1,a,Birgit Heese1,Julian Hofer1,Thomas Kanitz1,b,Moritz Haarig1,Kevin Ohneiser1,Martin Radenz1,Patric Seifert1,Annett Skupin1,Zhenping Yin1,2,Sabur F. Abdullaev3,Mika Komppula4,Maria Filioglou4,Elina Giannakaki4,5,Iwona S. Stachlewska6,Lucja Janicka6,Daniele Bortoli7,Eleni Marinou8,Vassilis Amiridis8,Anna Gialitaki8,9,c,Rodanthi-Elisavet Mamouri10,11,Boris Barja12,and Ulla Wandinger1Athena Augusta Floutsi et al.Athena Augusta Floutsi1,Holger Baars1,Ronny Engelmann1,Dietrich Althausen1,Albert Ansmann1,Stephanie Bohlmann1,a,Birgit Heese1,Julian Hofer1,Thomas Kanitz1,b,Moritz Haarig1,Kevin Ohneiser1,Martin Radenz1,Patric Seifert1,Annett Skupin1,Zhenping Yin1,2,Sabur F. Abdullaev3,Mika Komppula4,Maria Filioglou4,Elina Giannakaki4,5,Iwona S. Stachlewska6,Lucja Janicka6,Daniele Bortoli7,Eleni Marinou8,Vassilis Amiridis8,Anna Gialitaki8,9,c,Rodanthi-Elisavet Mamouri10,11,Boris Barja12,and Ulla Wandinger1
Received: 03 Nov 2022 – Discussion started: 18 Nov 2022
Abstract. This paper presents a collection of lidar-derived aerosol intensive optical properties for several aerosol types, namely the particle linear depolarization ratio, the extinction-to-backscatter ratio (lidar ratio) and the Ångström exponent. The data collection, named DeLiAn, is based on globally distributed, long-term, ground-based, multiwavelength, Raman and polarisation lidar measurements, conducted mainly with lidars that have been developed at the Leibniz Institute for Tropospheric Research. The intensive optical properties are presented at two wavelengths, 355 and 532 nm, for 13 aerosol categories. The categories cover the basic aerosol types (i.e., marine, pollution, continental European background, volcanic ash, smoke, mineral dust) as well as the most frequently observed mixtures they form. This extensive collection also incorporates more peculiar aerosol categories, including dried marine aerosol that, compared to marine aerosol, exhibits a significantly enhanced depolarization ratio (up to 15 %). Besides Saharan dust, additional mineral dust types related to their source region were identified due to their lower lidar ratios (Central Asian and Middle Eastern dust). In addition, extreme wildfire events (such as in north America and Australia) emitted smoke into the stratosphere showing significant different optical properties, i.e., high depolarization values (up to 25 %), compared to tropospheric smoke. The data collection reflects and underlines the variety of aerosol mixtures in the atmosphere and can be used for the development of aerosol typing schemes. The paper contains the currently most comprehensive overview of optical properties from aerosol lidar measurements and, therefore, provides a solid basis for future aerosol retrievals in the frame of both spaceborne and ground-based lidars. Furthermore, DeLiAn can assist the efforts for harmonization of satellite records of aerosol properties performed at different wavelengths.
The authors in their paper present a valuable collection of intensive properties of the aerosols, retrieved from ground-based lidar observations, which are associated to different aerosol types and mixtures. The paper provides a very comprehensive overview of the various campaigns and relevant publications, where these properties are presented and discussed. The paper is well written and structured and should be accepted for publication in AMT after considering some comments raised below.
Although such information might be available in the publications referenced, the authors should provide a comment, how they define from the measurement conditions an aerosol type as pure. Do they consider only the location of the site or they use also other tools such as trajectories or models?
Do the authors consider the ageing of the observed aerosols as a parameter for the typing (this was found in previous studies to be crucial especially for smoke)? A relevant comment should be added in the discussion.
It is confusing, as written, how the authors distinguish “pollution” type and “central European background”. More or less for both categories they use measurements from the same stations. They should provide a comment, why in certain cases they consider an observation as representative for pollution and why as background.
The authors group separately mixtures of different aerosol types, especially dust with smoke, dust with pollution and dust with marine. They should provide more details how they define an aerosol scene as a mixture. To my understanding they average all relevant scenes in order to provide a representative value for a certain mixture. Does the mixing ratio of the pure types involved play a role in the typing and do the authors claim that this ratio is not significantly different from location to location?
DeLiAn is a collection of lidar-derived aerosol intensive optical properties for several aerosol types, namely the particle linear depolarization ratio, the extinction-to-backscatter ratio (lidar ratio), and the Ångström exponent. The data collection is based on globally distributed, long-term, ground-based, multiwavelength, Raman and polarisation lidar measurements and currently covers two wavelengths, 355 and 532 nm, for 13 aerosol categories ranging from basic aerosol types to mixtures.
DeLiAn is a collection of lidar-derived aerosol intensive optical properties for several aerosol...
