Combining Mie–Raman and fluorescence observations: a step forward in aerosol classification with lidar technology

Atmospheric measurement techniques, Journal Year: 2022, Volume and Issue: 15(16), P. 4881 - 4900

Published: Aug. 29, 2022

Abstract. The paper presents an approach to revealing the variability in aerosol type, at high spatiotemporal resolution, by combining fluorescence and Mie–Raman lidar observations. multiwavelength system operation ATOLL (ATmospheric Observation liLLe) platform, Laboratoire d'Optique Atmosphérique, University of Lille, has included, since 2019, a wideband channel allowing derivation backscattering coefficient βF. capacity GF, which is ratio βF coefficient, intensive particle property, strongly changing with thus providing relevant basis for classification. In this first stage research, only two properties are used classification, namely depolarization 532 nm, δ532, capacity, GF. These considered because they can be derived resolution quite specific each type. particular, study, we use δ532–GF diagram identify smoke, dust, pollen, urban particles. We applied our new classification data obtained during 2020–2021 period, includes strong pollen episodes. was performed height about 60 m temporal better than 8 min.

Language: Английский

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Multiwavelength fluorescence lidar observations of smoke plumes

Atmospheric measurement techniques, Journal Year: 2023, Volume and Issue: 16(8), P. 2055 - 2065

Published: April 18, 2023

Abstract. A five-channel fluorescence lidar was developed for the study of atmospheric aerosol. The spectrum induced by 355 nm laser emission is analyzed in five spectral intervals using interference filters. Central wavelengths and widths these filters are, respectively, as follows: 438 29, 472 32, 513 560 40, 614 54 nm. relative calibration channels has been performed a tungsten–halogen lamp with color temperature 2800 K. This new system operated during summer–autumn 2022, when strong forest fires occurred Moscow region generated series smoke plumes this study. Our results demonstrate that, urban aerosol, maximal backscattering observed channel. For smoke, maximum shifted toward longer wavelengths, coefficients 472, have comparable values. Thus, from analysis ratios available channels, we show that it possible to identify layers. particle classification based on single-channel capacity (ratio elastic one) limitations at high humidity (RH). indeed decreases water uptake particles enhances scattering. However, variation does not exhibit any dependence RH can be therefore applied aerosol identification.

Language: Английский

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Wildfire smoke triggers cirrus formation: lidar observations over the eastern Mediterranean

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(22), P. 14097 - 14114

Published: Nov. 14, 2023

Abstract. The number of intense wildfires may increase further in upcoming years as a consequence climate change. It is therefore necessary to improve our knowledge about the role smoke system, with emphasis on impact particles evolution clouds, precipitation, and cloud radiative properties. Presently, one key aspect research whether or not wildfire can initiate cirrus formation. In this study, we present lidar observations over Limassol, Cyprus, from 27 October 3 November 2020, when extended fields crossed Mediterranean Basin Portugal Cyprus. We found strong evidence that aged (organic aerosol particles) originating North America triggered significant ice nucleation at temperatures −47 −53 ∘C caused formation layers. suggest crystals were nucleated just below tropopause presence serving ice-nucleating (INPs). main part 2–3 km thick layer was, however, lower stratosphere above tropopause. With actual radiosonde temperature relative humidity lidar-derived particle surface area concentrations used starting values, gravity wave simulations show lofting air by 100–200 m sufficient particles, leading crystal 1–100 L−1.

Language: Английский

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Measurement report: Violent biomass burning and volcanic eruptions – a new period of elevated stratospheric aerosol over central Europe (2017 to 2023) in a long series of observations

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(3), P. 1997 - 2021

Published: Feb. 14, 2024

Abstract. The highlight of the meanwhile 50 years lidar-based aerosol profiling at Garmisch-Partenkirchen has been measurements stratospheric since 1976. After a technical breakdown in 2016, they have continued with new, much more powerful system vertical range up to almost km a.s.l. (above sea level) that allowed for observing very weak volcanic 40 km. observations 2017 are characterized by number spectacular events, such as Raikoke plume equalling integrated backscatter coefficient Mt St Helens 1981 and severe smoke from several big fires North America Siberia coefficients maximum values after Pinatubo eruption. violent British Columbia gradually reached than 20 a.s.l., unprecedented our observations. sudden increase frequency strong events is difficult understand. Finally, underwater eruption on Tonga Islands southern Pacific January 2022 was detected between 25

Language: Английский

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Geometrical and optical properties of cirrus clouds in Barcelona, Spain: analysis with the two-way transmittance method of 4 years of lidar measurements

Atmospheric measurement techniques, Journal Year: 2024, Volume and Issue: 17(4), P. 1197 - 1216

Published: Feb. 20, 2024

Abstract. In this paper a statistical study of cirrus geometrical and optical properties based on 4 years continuous ground-based lidar measurements with the Barcelona (Spain) Micro Pulse Lidar (MPL) is analysed. First, review literature two-way transmittance method presented. This well-known inversion used to retrieve an aerosol–cloud layer between two molecular (i.e. aerosol cloud-free) regions below above, without need make any priori assumptions about their and/or microphysical properties. Second, simple mathematical expression proposed for both spaceborne systems. approach allows retrieval cloud depth, column ratio vertical profile backscatter coefficient. The illustrated using from MPL Cloud-Aerosol Orthogonal Polarization (CALIOP). Third, database then filtered identification criterion (and compared to) only radiosonde data. During period November 2018 September 2022, 367 high-altitude clouds were identified at 00:00 12:00 UTC, which 203 successfully inverted method. results these show that thickness 1.8 ± 1.1 km, mid-cloud temperature −51 8 ∘C linear depolarization 0.32 0.13. application yields average depth (COD) 0.36 0.45 mean effective 30 19 sr. Statistical errors associated retrievals are also provided. highest occurrence observed in spring majority (48 %) visible (0.03 < COD 0.3), followed by opaque (COD > 0.3) percentage 38 %. Together other sites, possible latitudinal dependencies have been analysed together correlations For example, we noted correlates positively base temperature, negatively height.

Language: Английский

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Annual cycle of aerosol properties over the central Arctic during MOSAiC 2019–2020 – light-extinction, CCN, and INP levels from the boundary layer to the tropopause

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(19), P. 12821 - 12849

Published: Oct. 12, 2023

Abstract. The MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition was largest field campaign ever conducted. offered unique opportunity to monitor and characterize aerosols clouds with high vertical resolution up 30 km height at latitudes from 80 90∘ N over an entire year (October 2019 September 2020). Without a clear knowledge complex aerosol layering, structures, dominant types their impact on cloud formation, full understanding meteorological processes in Arctic, thus advanced climate change research, is impossible. Widespread ground-based situ observations are insufficient provide these required data. In this article, summary our tropospheric profiles state-of-the-art multiwavelength polarization Raman lidar aboard icebreaker Polarstern presented. Particle optical properties, i.e., light-extinction thickness (AOT), estimates cloud-relevant properties such as number concentration condensation nuclei (CCN) ice-nucleating particles (INPs) discussed, separately lowest part troposphere (atmospheric boundary layer, ABL), within lower free (around 2000 m height), cirrus level close tropopause. particle INPs included study. A strong decrease amount winter moderate variations summer were observed terms extinction coefficient. 532 nm values dropped >50 Mm−1 surface <5 4–6 months. Lofted, aged wildfire smoke layers caused re-increase towards (June August 2020), much coefficients, frequently low 1–5 Mm−1, ABL. Aerosol removal, controlled by in-cloud below-cloud scavenging (widely suppressed very efficient summer) lowermost 1–2 atmosphere, seems be main reason differences between conditions. complete annual cycle AOT central could measured. This valuable addition summertime sun photometers Robotic Network (AERONET). line pronounced typical CCN concentrations (0.2 % supersaturation level) ranged 50–500 cm−3 10–100 (at m), however, roughly constant throughout year, mostly 100 cm−3. contrast also given ABL which control ice production low-level clouds. While soil dust (from surrounding continents) probably INP type during autumn, winter, spring months, local sea spray (with biogenic component) dominate nucleation months (June–August). vs. 2–3 orders magnitude is, mainly temperature contrast. event occurrence long-lasting layer upper stratosphere. Our suggest that triggered formation tropopause October May 2020.

Language: Английский

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Derivation of depolarization ratios of aerosol fluorescence and water vapor Raman backscatters from lidar measurements

Atmospheric measurement techniques, Journal Year: 2024, Volume and Issue: 17(3), P. 1023 - 1036

Published: Feb. 12, 2024

Abstract. Polarization properties of the fluorescence induced by polarized laser radiation are widely considered in laboratory studies. In lidar observations, however, only total backscattered power is analyzed. this paper we present results obtained with a modified Mie–Raman–fluorescence operated at ATOLL observatory, Laboratoire d'Optique Atmosphérique, University Lille, France, allowing us to measure depolarization ratios 466 nm (δF) and water vapor Raman backscatter. Measurements were performed May–June 2023 during Alberta forest fires season when smoke plumes almost continuously transported over Atlantic Ocean towards Europe. During same period, from sources also detected analyzed Moscow, General Physics Institute (GPI), five-channel able backscattering 438, 472, 513, 560 614 nm. Results demonstrate that, inside planetary boundary layer (PBL), urban aerosol maximal 438 nm, then it gradually decreases increase wavelength. The layers observed within 4–6 km height maximum 513 while upper troposphere, shifts Regarding ratio, for its value typically varies 45 %–55 % range. ratio 408 shown be quite low (2±0.5 %) absence because narrowband interference filter (0.3 nm) channel selects strongest vibrational lines spectrum. As result, sensitive presence strongly depolarized can used evaluation contribution measured mixing ratio.

Language: Английский

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Fluorescence properties of long-range-transported smoke: insights from five-channel lidar observations over Moscow during the 2023 wildfire season

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(3), P. 1603 - 1615

Published: Feb. 5, 2025

Abstract. The fluorescence lidar at the Prokhorov General Physics Institute (Moscow) was utilized to study smoke transported over Atlantic during wildfire season from May September 2023. system, which is based on a tripled Nd : YAG laser, performs measurements across five spectral intervals centered wavelengths of 438, 472, 513, 560 and 614 nm. This configuration enables assessment dependence backscattering broad range altitudes, planetary boundary layer (PBL) middle upper troposphere (MUT). capacity smoke, defined as ratio aerosol laser wavelength, exhibits significant variation in MUT, with changes up factor 3. likely indicative differences relative concentration organic compounds within smoke. Analysis more than 40 episodes has enabled an evaluation height properties. Observations reveal that generally increases altitude, suggesting higher MUT compared lower troposphere. Additionally, consistently show spectra urban aerosol. Urban tends decrease gradually whereas peak observed 513 nm channels. distinction provides effective means separating technique applied analysis events where descended into PBL, demonstrating its utility distinguishing between these types.

Language: Английский

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Invisible aerosol layers: improved lidar detection capabilities by means of laser-induced aerosol fluorescence

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(7), P. 3995 - 4011

Published: April 9, 2025

Abstract. One of the most powerful instruments for studying aerosol particles and their interactions with environment is atmospheric lidar. In recent years, fluorescence lidar has emerged as a useful tool identifying due to its link biological content. Since 2022, this technique been implemented in Leipzig, Germany. This paper describes experimental setup data analysis, special emphasis on characterization new channel centered at 466 nm. The capabilities are examined corroborated through several case studies. Most measurement cases considered from spring summer 2023, when large amounts biomass-burning huge forest fires Canada were transported Europe. observed layers characterized. For wildfire smoke, capacity was typically range 2×10-4–7 × 10−4, which aligns well values reported literature. key aspects study technique, can potentially improve not only typing but even detection particles. an apparently low load, clearly revealed presence that detectable traditional elastic-backscatter channels. capability discussed detail linked fact backscattering related only. A second area potential distinction between non-activated hydrometeors, given water's inability exhibit fluorescence. smoke–cirrus suggests influence layer cloud formation, it seems affect coefficient within passing time. These aforementioned applications promise advancements towards more detailed view aerosol–cloud interaction problem.

Language: Английский

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Retrieval and analysis of the composition of an aerosol mixture through Mie–Raman–fluorescence lidar observations

Atmospheric measurement techniques, Journal Year: 2024, Volume and Issue: 17(13), P. 4137 - 4152

Published: July 15, 2024

Abstract. In the atmosphere, aerosols can originate from numerous sources, leading to mixing of different particle types. This paper introduces an approach partitioning aerosol mixtures in terms backscattering coefficients. The method utilizes data collected Mie–Raman–fluorescence lidar, with primary input information being coefficient (β), depolarization ratio (δ), and fluorescence capacity (GF). is defined as at laser wavelength. By solving a system equations that model these three properties (β, δ GF), it possible characterize three-component mixture. Specifically, assesses contributions smoke, urban, dust overall 532 nm. It important note (δ GF) may exhibit variations even within specified type. To estimate associated uncertainty, we employ Monte Carlo technique, which assumes GF are random values uniformly distributed predefined intervals. each run, solution obtained. Rather than relying on singular solution, average computed across whole set solutions, their dispersion serves metric for uncertainty. methodology was tested using observations conducted ATOLL (ATmospheric Observation liLLe) observatory, Laboratoire d'Optique Atmosphérique, University Lille, France.

Language: Английский

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