Monitoring of the Eyjafjallajökull volcanic aerosol plume over the Iberian Peninsula by means of four EARLINET lidar stations
TL;DR: In this article, the authors performed intensively over the Iberian Peninsula (IP) during the eruption of the Eyjafjallajokull volcano (Iceland) in April-May 2010.
Abstract: . Lidar and sun-photometer measurements were performed intensively over the Iberian Peninsula (IP) during the eruption of the Eyjafjallajokull volcano (Iceland) in April–May 2010. The volcanic plume reached all the IP stations for the first time on 5 May 2010. A thorough study of the event was conducted for the period 5–8 May. Firstly, the spatial and temporal evolution of the plume was described by means of lidar and sun-photometer measurements supported with backtrajectories. The volcanic aerosol layers observed over the IP were rather thin (
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TL;DR: In this article , 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, are presented at two wavelengths, 355 and 532 nm, for 13 aerosol categories.
Abstract: 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 polarization 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 significantly 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 most up-to-date and 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 the harmonization of satellite records of aerosol properties performed at different wavelengths.
3 citations
TL;DR: In this paper , a long-term study of the relative mass contribution and vertical impact of the volcanic components, ash and non-ash particles separately, during the eruptive activity was carried out in this work.
2 citations
01 May 2021
2 citations
TL;DR: In this paper , a series of thick stratospheric plumes between 36 and 18 km altitude have been characterized along time, with aerosol optical depth as high as 0.84 at 532 nm and negative Angström exponents for the main layers down to −0.8 ± 0.8.
Abstract: The exceptionally violent eruption of the Hunga Tonga‐Hunga Ha'apai volcano (HTHH) of 15 January 2022, in the South Pacific, was associated with a powerful blast that injected gases, steam and aerosol to unprecedentedly high altitudes. This article details unique observations of the young volcanic plume from ground‐based lidars at Reunion (21°S, 55°E). Two lidars, operating at wavelengths of 355 and 532 nm, recorded the plume overhead from 19 January until 28 January providing the vertical structure and the optical properties of the plume. A series of thick stratospheric plumes between 36 and 18 km altitude have been characterized along time, with aerosol optical depth as high as 0.84 at 532 nm and negative Angström exponents for the main layers down to −0.8 ± 0.8. The diversity of plumes properties is explained by the injection heights of the volcanic material as well as stratospheric dynamics and chemistry.
1 citations
TL;DR: In this article , a new method to estimate aerosol radiative forcing (ARF) on photosynthetically active radiation (PAR) is proposed using as input only the solar position and global irradiance measurements, available in many radiometric stations worldwide.
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TL;DR: The operation and philosophy of the monitoring system, the precision and accuracy of the measuring radiometers, a brief description of the processing system, and access to the database are discussed.
6,535 citations
01 Jan 2010
2,302 citations
TL;DR: Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) is a two-wavelength polarization lidar that performs global profiling of aerosols and clouds in the troposphere and lower stratosphere as discussed by the authors.
Abstract: The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) is a two-wavelength polarization lidar that performs global profiling of aerosols and clouds in the troposphere and lower stratosphere. CALIOP is the primary instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite, which has flown in formation with the NASA A-train constellation of satellites since May 2006. The global, multiyear dataset obtained from CALIOP provides a new view of the earth’s atmosphere and will lead to an improved understanding of the role of aerosols and clouds in the climate system. A suite of algorithms has been developed to identify aerosol and cloud layers and to retrieve a variety of optical and microphysical properties. CALIOP represents a significant advance over previous space lidars, and the algorithms that have been developed have many innovative aspects to take advantage of its capabilities. This paper provides a brief overview of the CALIPSO mission, the CA...
1,833 citations
"Monitoring of the Eyjafjallajökull ..." refers background in this paper
...It is worth noting that the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) lidar flying on board CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) (Winker et al., 2009) made an overpass over the eastern IP on 6 May around 02:40 UTC and also detected very thin aerosol plumes identified as dust and polluted dust – in which categories volcanic aerosols do fit – up to 10 km....
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...…Lidar with Orthogonal Polarization) lidar flying on board CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) (Winker et al., 2009) made an overpass over the eastern IP on 6 May around 02:40 UTC and also detected very thin aerosol plumes identified as dust and…...
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TL;DR: In this article, a new inversion concept for simultaneously retrieving aerosol size distribution, complex refractive index, and single scattering albedo from spectral measurements of direct and diffuse radiation was proposed.
Abstract: Sensitivity studies are conducted regarding aerosol optical property retrieval from radiances measured by ground-based Sun-sky scanning radiometers of the Aerosol Robotic Network (AERONET). These studies focus on testing a new inversion concept for simultaneously retrieving aerosol size distribution, complex refractive index, and single- scattering albedo from spectral measurements of direct and diffuse radiation. The perturbations of the inversion resulting from random errors, instrumental offsets, and known uncertainties in the atmospheric radiation model are analyzed. Sun or sky channel miscalibration, inaccurate azimuth angle pointing during sky radiance measurements, and inaccuracy in accounting for surface reflectance are considered as error sources. The effects of these errors on the characterization of three typical and optically distinct aerosols with bimodal size distributions (weakly absorbing water-soluble aerosol, absorbing biomass-burning aerosol, and desert dust) are considered. The aerosol particles are assumed in the retrieval to be polydispersed homogeneous spheres with the same complex refractive index. Therefore we also examined how inversions with such an assumption bias the retrievals in the case of nonspherical dust aerosols and in the case of externally or internally mixed spherical particles with different refractive indices. The analysis shows successful retrieval of all aerosol characteristics (size distribution, complex refractive index, and single-scattering albedo), provided the inversion includes the data combination of spectral optical depth together with sky radiances in the full solar almucantar (with angular coverage of scattering angles up to 100" or more). The retrieval accuracy is acceptable for most remote sensing applications even in the presence of rather strong systematic or random uncertainties in the measurements. The major limitations relate to the characterization of low optical depth situations for all aerosol types, where high relative errors may occur in the direct radiation measurements of aerosol optical depth. Also, the results of tests indicate that a decrease of angular coverage of scattering (scattering angles of 75" or less) in the sky radiance results in the loss of practical information about refractive index. Accurate azimuth angle pointing is critical for the characterization of dust. Scattering by nonspherical dust particles requires special analysis, whereby approximation of the aerosol by spheres allows us to derive single-scattering albedo by inverting spectral optical depth together with sky radiances in the full solar almucantar. Inverting sky radiances measured in the first 40" scattering angle only, where nonspherical effects are minor, results in accurate retrievals of aerosol size distributions of nonspherical particles.
1,562 citations
"Monitoring of the Eyjafjallajökull ..." refers background in this paper
...Even though the AERONET AOT uncertainty is known to be ≤ ±0.01 for wavelengths greater than 440 nm (Holben et al., 1998; Dubovik et al., 2000), here the AOT at 500 nm is expressed with three digits in order to minimize differences due to truncation in the calculation of the fine and coarse mode…...
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...01 for wavelengths greater than 440 nm (Holben et al., 1998; Dubovik et al., 2000), here the AOT at 500 nm is expressed with three digits in order to minimize differences due to truncation in the calculation of the fine and coarse mode fractions....
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TL;DR: A restatement of the more general solution of Fernald et al.l which is also applicable to mildly turbid atmospheres where both aerosol and molecular scatterers must be considered in the analysis.
Abstract: There have been many discussions of solutions to the lidar equation for elastic scattering (e.g., Fernald et al.,' Klett, 2 Davis, and Collis and Russell ). Most of these are simply variations on Hitschfeld and Bordan's5 solution for meteorological radars. Klett 2 recently restated this solution in a very convenient form for the analysis of lidar observations collected in very turbid atmospheres. His paper has prompted a restatement of the more general solution of Fernald et al.l which is also applicable to mildly turbid atmospheres where both aerosol and molecular scatterers must be considered in the analysis. This has led to a simple numerical scheme for the computer analysis of lidar measurements. The lidar equation for two distinct classes of scatters (Fernald et al.') is
1,558 citations
"Monitoring of the Eyjafjallajökull ..." refers methods in this paper
...Phys., 12, 3115–3130, 2012 www.atmos-chem-phys.net/12/3115/2012/ All measurements were inverted using the two-component elastic lidar inversion algorithm (Fernald, 1984; Sasano and Nakane, 1984; Klett, 1985) and a constant lidar ratio of 50 sr....
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...All measurements were inverted using the two-component elastic lidar inversion algorithm (Fernald, 1984; Sasano and Nakane, 1984; Klett, 1985) and a constant lidar ratio of 50 sr....
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