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5. Optical Properties of Canadian Biomass Burning Particles Over Europe Observed with Calipso and Ground-Based Lidar Systems

Author

Papanikolaou Christina-Anna, Giannakaki Elina, Papayannis Alex, Tombrou Maria, Mylonaki Maria, and Soupiona Ourania

Subjects
Physics, QC1-999
Abstract

A long-lasting biomass burning event affected Europe from 27 August to 3 September 2018. The biomass burning aerosol layers were observed with ground- and space-based lidars in heights ranged between 2-7 km (a.s.l.). The mean backscatter coefficient for the ground-based stations ranged between 0.29 and 1.51 Mm-1sr-1, while the CALIPSO retrieved values ranged between 0.43 and 1.83 Mm-1sr-1. Moreover, the mean Ångström exponent (AEb) values, relevant to backscatter, ranged from 0.83 to 1.04 for the aforementioned lidar stations. At the same time, the mean AEb values obtained from CALIPSO ranged between 0.17 and 1.89. The mean particle depolarization ratio ranged between 0.037 and 0.080.

Published
2020
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6. Saharan Dust Events Over the Northern Mediterranean: 4 Years of Measurements Over 4 Earlinet Stations

Author

Soupiona Ourania, Papayannis Alex, Mylonaki Maria, Papagiannopoulos Nikolaos, Ortiz-Amezcua Pablo, Mamouri Rodanthi E., Groß Silke, Papanikolaou Christina A., and Kokkalis Panagiotis

Subjects
Physics, QC1-999
Abstract

Four years (2014-2017) of observations of depolarization Raman Lidar systems of four EARLINET (European Aerosol research Lidar Network) stations [from West to East: Granada (Spain), Potenza (Italy), Athens (Greece) and Limassol (Cyprus)] were collected and used to a statistical analysis of Saharan dust events over Mediterranean basin. In this study, emphasis is given to the consistency of the particle linear depolarization ratio (δp532), the extinction-to-backscatter ratio mentioned as Lidar Ratio (LR532) and the Aerosol Optical Thickness (AOT532) within the observed Saharan dust layers, corresponding to the visible range (532 nm). Geometrical properties and clusters of aerosol mixtures are also presented. Our clustering was based on previous classification by airborne High Spectral Resolution Lidar (HSRL) observations and was further supported by backward trajectory analysis. We found mean δp532 values of 0.24±0.05, 0.26±0.06, 0.28±0.05 and 0.28±0.04, mean LR532 values of 52±8 sr, 51±9 sr, 52±9 sr and 49±6 sr, mean AOT532 values of 0.40±0.31, 0.11±0.07, 0.12±0.10 and 0.32±0.17 and mean layer thicknesses of 3392±1458 m, 2150±1082 m, 1872±816 m and 1716±567 m for Granada, Potenza, Athens and Limassol respectively. This work could assist in bridging the existing gaps related to the extensive and intensive dust aerosol properties over the Mediterranean and enriching the bibliography about mixed aerosol layers from different sources (e.g. dust and biomass burning (BB) aerosols, dust and urban/ industrial aerosols).

Published
2020
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7. Synergetic Observations by Ground-Based and Space Lidar Systems and Aeronet Sun-Radiometers: A Step to Advanced Regional Monitoring of Large Scale Aerosol Changes

Author

Chaikovsky Anatoli, Bril Andrey, Dubovik Oleg, Fedarenka Anton, Goloub Philippe, Hu Qiaoyun, Lopatin Anton, Lapyonok Tatyana, Miatselskaya Natallia, Torres Benjamin, Fuertes David, Peshcharankou Vladislau, Podvin Thierry, Popovici Ioana, Liu Dong, Li Zhengqiang, Soupiona Ourania, Mylonaki Maria, Mona Lucia, Giunta Aldo, Papagiannopoulos Nikolaos, Perrone Maria Rita, Romano Salvatore, Balis Dimitris, Siomos Nikolaos, Voudouri Kalliopi-Artemis, Belegante Livio, Nicolae Doina, Ene Dragos, Ajtai Nicolae, Stefanie Horatiu, Amiridis Vassilis, Tsekeri Alexandra, Bortoli Daniele, Costa Maria Joao, Mattis Ina, Rocadenbosch Francesc, Rodríguez-Gomez Alejandro, Sicard Michael, Fernandez Alfonso J., Molero Francisco, Althausen Dietrich, Baars Holger, Rascado Juan Luis Guerrero, Ortiz-Amezcua Pablo, Oltra José Antonio Benavent, Bedoya-Velásquez Andrés Esteban, Román Roberto, Alados-Arboledas Lucas, Balin Yurii, Kokhanenko Grigorii, Penner Ivan, Chen Boris, Sverdlik Leonid, Milinevsky Genadi, Sugimoto Nobuo, Shimizu Atsushi, Nishizawa Tomoaki, Kudo Rei, Sano Itaru, Yasunari Teppei J., Irie Hitoshi, Takemura Toshihiko, Kim Sang-Woo, Anh Nguyen Xuan, Thanh Pham Xuan, Pietruczuk Aleksander, Stachlewska Iwona S., Sannino Alessia, Wang Xuan, and Boselli Antonela

Subjects
Physics, QC1-999
Abstract

The paper presents the preliminary results of the lidar&radiometer measurement campaign (LRMC-2017), estimation of statistical relations between aerosol mode concentrations retrieved from CALIOP and ground-based lidar stations and case study of fire smoke events in the Eurasian regions using combined ground-based and space lidar and radiometer observations.

Published
2020
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8. Evaluation of a Commercial Aerosol Lidar Scanner for Urban Pollution Monitoring.

Author

Kostopoulos, Vassilis, Soupiona, Ourania, Georgoussis, Georgios, Georgiou, Thanasis, Kampouri, Anna, Drakaki, Eleni, and Amiridis, Vasilis

Subjects
ATMOSPHERIC aerosols, URBAN pollution, LIDAR, PARTICULATE matter
Abstract

Remote sensing of particulate matter (PM) absolute concentration levels can address the need for continuous wide-area monitoring in urban environments, which arises from the adverse effects of air pollution on human health. Raymetrics PMeye is a unique aerosol monitoring system designed around a state-of-the-art polarization scanning UV lidar that offers large-area PM concentration monitoring and high spatial resolution source localization. The PMeye lidar employs a novel inversion scheme for converting raw lidar signals to PM concentrations. This study demonstrates the effectiveness and accuracy of remote monitoring PM concentration measurement results in the region of Attica, Greece. Potential synergistic use with inversion modeling techniques and dispersion models to support an advanced warning system for the population and local authorities of the Athens metropolitan area is also discussed. [ABSTRACT FROM AUTHOR]

Published
2023
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10. Vertical Profiling of Fresh Biomass Burning Aerosol Optical Properties over the Greek Urban City of Ioannina, during the PANACEA Winter Campaign

Author

Papanikolaou, Christina-Anna, primary, Papayannis, Alexandros, additional, Mylonaki, Maria, additional, Foskinis, Romanos, additional, Kokkalis, Panagiotis, additional, Liakakou, Eleni, additional, Stavroulas, Iasonas, additional, Soupiona, Ourania, additional, Hatzianastassiou, Nikolaos, additional, Gavrouzou, Maria, additional, Kralli, Eleni, additional, and Anagnou, Dimitra, additional

Published
2022
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11. ATHLI16: the ATHens Lidar Intercomparison campaign

Author

Amodeo Aldo, D’Amico Giuseppe, Giunta Aldo, Papagiannopoulos Nikolaos, Papayannis Alex, Argyrouli Athina, Mylonaki Maria, Tsaknakis Georgios, Kokkalis Panos, Soupiona Ourania, and Tzanis Chris

Subjects
Physics, QC1-999
Abstract

The results of the ATHLI16 (ATHens Lidar Intercomparison) campaign, held in Athens from 26/09 to 07/10 2016 are presented. The campaign was performed within the Lidar Calibration Centre activities (EU H2020 ACTRIS-2 project) to assess the performance of the EOLE lidar system (NTUA, Athens, Greece), operating within EARLINET, by comparing against the EARLINET reference lidar system MUSA (CNR-IMAA, Potenza, Italy). For both lidars only products retrieved by the EARLINET Single Calculus Chain have been compared.

Published
2018
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12. Seventeen-year systematic measurements of dust aerosol optical properties using the eole ntua lidar system (2000-2016)

Author

Soupiona Ourania, Mylonaki Maria, Papayannis Alexandros, Argyrouli Athina, Kokkalis Panayotis, and Tsaknakis Georgios

Subjects
Physics, QC1-999
Abstract

A comprehensive analysis of the seasonal variability of the optical properties of Saharan dust aerosols over Athens, Greece, is presented for a 17-year time period (2000-2016), as derived from multi-wavelength Raman lidar measurements (57 dust events with more than 80 hours of measurements). The profiles of the derived aerosol optical properties (aerosol backscatter and extinction coefficients, lidar ratio and aerosol Ångström exponent) at 355 nm are presented. For these dust events we found a mean value of the lidar ratio of ~52±13 sr at 355 nm and of ~58±8 sr (not shown) at 532 nm (2-4 km a.s.l. height). For our statistical analysis, presented here, we used monthly-mean values and time periods under cloud-free conditions. The number of dust events was greatest in late spring, summer, and early autumn periods. In this paper we also present a selected case study (04 April 2016) of desert dust long-range transport from the Saharan desert.

Published
2018
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13. Earlinet single calculus chain: new products overview

Author

D’Amico Giuseppe, Mattis Ina, Binietoglou Ioannis, Baars Holger, Mona Lucia, Amato Francesco, Kokkalis Panos, Rodríguez-Gómez Alejandro, Soupiona Ourania, and Kalliopi-Artemis Voudouri

Subjects
Physics, QC1-999
Abstract

The Single Calculus Chain (SCC) is an automatic and flexible tool to analyze raw lidar data using EARLINET quality assured retrieval algorithms. It has been already demonstrated the SCC can retrieve reliable aerosol backscatter and extinction coefficient profiles for different lidar systems. In this paper we provide an overview of new SCC products like particle linear depolarization ratio, cloud masking, aerosol layering allowing relevant improvements in the atmospheric aerosol characterization.

Published
2018
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14. Aerosol optical properties variability during biomass burning events observed by the eole-aias depolarization lidars over Athens, Greece (2007-2016)

Author

Mylonaki Maria, Papayannis Alexandros, Mamouri Rodanthi, Argyrouli Athina, Kokkalis Panagiotis, Tsaknakis Georgios, and Soupiona Ourania

Subjects
Physics, QC1-999
Abstract

The EOLE multi-wavelength aerosol Ramandepolarization lidar, and the AIAS depolarization lidar, in synergy with a sun photometer (CIMEL), were used, in the period 2007-2016, to provide the vertical profiles of the aerosol optical properties over Athens, Greece. More than 30 biomass burning events (fresh and aged smoke particles) were observed, with smoke layers between 1.5 up to 4-5 km height, while their duration ranged from 1-3 days. Lidar ratio (LR) values ranged from 40-105 sr (at 355 nm) and from 40-100 sr (at 532 nm), while the linear particle depolarization ratio (LPDR) at both 355 and 532 nm, remained

Published
2018
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15. Optical and Microphysical Properties of Aged Biomass Burning Aerosols and Mixtures, Based on 9-Year Multiwavelength Raman Lidar Observations in Athens, Greece

Author

Mylonaki, Maria, primary, Papayannis, Alexandros, additional, Anagnou, Dimitra, additional, Veselovskii, Igor, additional, Papanikolaou, Christina-Anna, additional, Kokkalis, Panagiotis, additional, Soupiona, Ourania, additional, Foskinis, Romanos, additional, Gidarakou, Marilena, additional, and Kralli, Eleni, additional

Published
2021
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16. Radiative Effect and Mixing Processes of a Long-Lasting Dust Event over Athens, Greece, during the COVID-19 Period

Author

Kokkalis, Panagiotis, primary, Soupiona, Ourania, additional, Papanikolaou, Christina-Anna, additional, Foskinis, Romanos, additional, Mylonaki, Maria, additional, Solomos, Stavros, additional, Vratolis, Stergios, additional, Vasilatou, Vasiliki, additional, Kralli, Eleni, additional, Anagnou, Dimitra, additional, and Papayannis, Alexandros, additional

Published
2021
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18. OPTICAL PROPERTIES OF CANADIAN BIOMASS BURNING PARTICLES OVER EUROPE OBSERVED WITH CALIPSO AND GROUND-BASED LIDAR SYSTEMS

Author

Papanikolaou, Christina-Anna Giannakaki, Elina Papayannis, Alex and Tombrou, Maria Mylonaki, Maria Soupiona, Ourania

Abstract

A long-lasting biomass burning event affected Europe from 27 August to 3 September 2018. The biomass burning aerosol layers were observed with ground- and space -based lidars in heights ranged between 2-7 km (a.s.l.). The mean backscatter coefficient for the ground-based stations ranged between 0.29 and 1.51 Mm(-1)sr(-1), while the CALIPSO retrieved values ranged between 0.43 and 1.83 Mm(-1)sr(-1). Moreover, the mean Angstrom exponent (AE(b)) values, relevant to backscatter, ranged from 0.83 to 1.04 for the aforementioned lidar stations. At the same time, the mean AE(b) values obtained from CALIPSO ranged between 0.17 and 1.89. The mean particle depolarization ratio ranged between 0.037 and 0.080.

Published
2020

19. EARLINET observations of Saharan dust intrusions over the northern Mediterranean region (2014–2017): properties and impact on radiative forcing

Author

Soupiona, Ourania, primary, Papayannis, Alexandros, additional, Kokkalis, Panagiotis, additional, Foskinis, Romanos, additional, Sánchez Hernández, Guadalupe, additional, Ortiz-Amezcua, Pablo, additional, Mylonaki, Maria, additional, Papanikolaou, Christina-Anna, additional, Papagiannopoulos, Nikolaos, additional, Samaras, Stefanos, additional, Groß, Silke, additional, Mamouri, Rodanthi-Elisavet, additional, Alados-Arboledas, Lucas, additional, Amodeo, Aldo, additional, and Psiloglou, Basil, additional

Published
2020
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23. Saharan dust intrusions over the northern Mediterranean region in the frame of EARLINET (2014–2017): Properties and impact in radiative forcing

Author

Soupiona, Ourania, primary, Papayannis, Alexandros, additional, Kokkalis, Panagiotis, additional, Foskinis, Romanos, additional, Sánchez Hernández, Guadalupe, additional, Ortiz-Amezcua, Pablo, additional, Mylonaki, Maria, additional, Papanikolaou, Christina-Anna, additional, Papagiannopoulos, Nikolaos, additional, Samaras, Stefanos, additional, Groß, Silke, additional, Mamouri, Rodanthi-Elisavet, additional, Alados-Arboledas, Lucas, additional, Amodeo, Aldo, additional, and Psiloglou, Basil, additional

Published
2020
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24. The unprecedented 2017–2018 stratospheric smoke event: decay phase and aerosol properties observed with the EARLINET

Author

Baars, Holger, primary, Ansmann, Albert, additional, Ohneiser, Kevin, additional, Haarig, Moritz, additional, Engelmann, Ronny, additional, Althausen, Dietrich, additional, Hanssen, Ingrid, additional, Gausa, Michael, additional, Pietruczuk, Aleksander, additional, Szkop, Artur, additional, Stachlewska, Iwona S., additional, Wang, Dongxiang, additional, Reichardt, Jens, additional, Skupin, Annett, additional, Mattis, Ina, additional, Trickl, Thomas, additional, Vogelmann, Hannes, additional, Navas-Guzmán, Francisco, additional, Haefele, Alexander, additional, Acheson, Karen, additional, Ruth, Albert A., additional, Tatarov, Boyan, additional, Müller, Detlef, additional, Hu, Qiaoyun, additional, Podvin, Thierry, additional, Goloub, Philippe, additional, Veselovskii, Igor, additional, Pietras, Christophe, additional, Haeffelin, Martial, additional, Fréville, Patrick, additional, Sicard, Michaël, additional, Comerón, Adolfo, additional, Fernández García, Alfonso Javier, additional, Molero Menéndez, Francisco, additional, Córdoba-Jabonero, Carmen, additional, Guerrero-Rascado, Juan Luis, additional, Alados-Arboledas, Lucas, additional, Bortoli, Daniele, additional, Costa, Maria João, additional, Dionisi, Davide, additional, Liberti, Gian Luigi, additional, Wang, Xuan, additional, Sannino, Alessia, additional, Papagiannopoulos, Nikolaos, additional, Boselli, Antonella, additional, Mona, Lucia, additional, D'Amico, Giuseppe, additional, Romano, Salvatore, additional, Perrone, Maria Rita, additional, Belegante, Livio, additional, Nicolae, Doina, additional, Grigorov, Ivan, additional, Gialitaki, Anna, additional, Amiridis, Vassilis, additional, Soupiona, Ourania, additional, Papayannis, Alexandros, additional, Mamouri, Rodanthi-Elisaveth, additional, Nisantzi, Argyro, additional, Heese, Birgit, additional, Hofer, Julian, additional, Schechner, Yoav Y., additional, Wandinger, Ulla, additional, and Pappalardo, Gelsomina, additional

Published
2019
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25. The unprecedented 2017 - 2018 stratospheric smoke event: decay phase and aerosol properties observed with the EARLINET

Author

Baars, Holger, Ansmann, Albert, Ohneiser, Kevin, Haarig, Moritz, Engelmann, Ronny, Althausen, Dietrich, Hanssen, Ingrid, Gausa, Michael, Pietruczuk, Aleksander, Szkop, Artur, Stachlewska, Iwona S., Wang, Dongxiang, Reichardt, Jens, Skupin, Annett, Mattis, Ina, Trickl, Thomas, Vogelmann, Hannes, Navas-Guzmán, Francisco, Haefele, Alexander, Acheson, Karen, Ruth, Albert A., Tatarov, Boyan, Müller, Detlef, Hu, Qiaoyun, Podvin, Thierry, Goloub, Philippe, Veselovskii, Igor, Pietras, Christophe, Haeffelin, Martial, Fréville, Patrick, Sicard, Michaël, Comerón, Adolfo, Fernández García, Alfonso Javier, Molero Menéndez, Francisco, Córdoba-Jabonero, Carmen, Guerrero-Rascado, Juan Luis, Alados-Arboledas, Lucas, Bortoli, Daniele, Costa, Maria João, Dionisi, Davide, Liberti, Gian Luigi, Wang, Xuan, Sannino, Alessia, Papagiannopoulos, Nikolaos, Boselli, Antonella, Mona, Lucia, D&amp, apos, Amico, Giuseppe, Romano, Salvatore, Perrone, Maria Rita, Belegante, Livio, Nicolae, Doina, Grigorov, Ivan, Gialitaki, Anna, Amiridis, Vassilis, Soupiona, Ourania, Papayannis, Alexandros, Mamouri, Rodanthi-Elisaveth, Nisantzi, Argyro, Heese, Birgit, Hofer, Julian, Schechner, Yoav Y., Wandinger, Ulla, and Pappalardo, Gelsomina

Subjects
Earth sciences, EARLINET, stratospheric smoke, ddc:550, lidar
Abstract

Six months of stratospheric aerosol observations with the European Aerosol Research Lidar Network (EARLINET) from August 2017 to January 2018 are presented. The decay phase of an unprecedented, record-breaking stratospheric perturbation caused by wildfire smoke is reported and discussed in terms of geometrical, optical, and microphysical aerosol properties. Enormous amounts of smoke were injected into the upper troposphere and lower stratosphere over fire areas in western Canada on 12 August 2017 during strong thunderstorm–pyrocumulonimbus activity. The stratospheric fire plumes spread over the entire Northern Hemisphere in the following weeks and months. Twenty-eight European lidar stations from northern Norway to southern Portugal and the eastern Mediterranean monitored the strong stratospheric perturbation on a continental scale. The main smoke layer (over central, western, southern, and eastern Europe) was found at heights between 15 and 20 km since September 2017 (about 2 weeks after entering the stratosphere). Thin layers of smoke were detected at heights of up to 22–23 km. The stratospheric aerosol optical thickness at 532 nm decreased from values > 0.25 on 21–23 August 2017 to 0.005–0.03 until 5–10 September and was mainly 0.003–0.004 from October to December 2017 and thus was still significantly above the stratospheric background (0.001–0.002). Stratospheric particle extinction coefficients (532 nm) were as high as 50–200 Mm−1 until the beginning of September and on the order of 1 Mm−1 (0.5–5 Mm−1) from October 2017 until the end of January 2018. The corresponding layer mean particle mass concentration was on the order of 0.05–0.5 µg m−3 over these months. Soot particles (light-absorbing carbonaceous particles) are efficient ice-nucleating particles (INPs) at upper tropospheric (cirrus) temperatures and available to influence cirrus formation when entering the tropopause from above. We estimated INP concentrations of 50–500 L−1 until the first days in September and afterwards 5–50 L−1 until the end of the year 2017 in the lower stratosphere for typical cirrus formation temperatures of −55 ∘C and an ice supersaturation level of 1.15. The measured profiles of the particle linear depolarization ratio indicated a predominance of nonspherical smoke particles. The 532 nm depolarization ratio decreased slowly with time in the main smoke layer from values of 0.15–0.25 (August–September) to values of 0.05–0.10 (October–November) and

Published
2019
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26. Optical Properties of Canadian Biomass Burning Particles Over Europe Observed with Calipso and Ground-Based Lidar Systems.

Author

Liu, D., Wang, Y., Wu, Y., Gross, B., Moshary, F., Papanikolaou, Christina-Anna, Giannakaki, Elina, Papayannis, Alex, Tombrou, Maria, Mylonaki, Maria, and Soupiona, Ourania

Subjects
OPTICAL properties, BIOMASS, AEROSOLS, BACKSCATTERING
Abstract

A long-lasting biomass burning event affected Europe from 27 August to 3 September 2018. The biomass burning aerosol layers were observed with ground- and space-based lidars in heights ranged between 2-7 km (a.s.l.). The mean backscatter coefficient for the ground-based stations ranged between 0.29 and 1.51 Mm-1sr-1, while the CALIPSO retrieved values ranged between 0.43 and 1.83 Mm-1sr-1. Moreover, the mean Ångström exponent (AEb) values, relevant to backscatter, ranged from 0.83 to 1.04 for the aforementioned lidar stations. At the same time, the mean AEb values obtained from CALIPSO ranged between 0.17 and 1.89. The mean particle depolarization ratio ranged between 0.037 and 0.080. [ABSTRACT FROM AUTHOR]

Published
2020
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27. Saharan Dust Events Over the Northern Mediterranean: 4 Years of Measurements Over 4 Earlinet Stations.

Author

Liu, D., Wang, Y., Wu, Y., Gross, B., Moshary, F., Soupiona, Ourania, Papayannis, Alex, Mylonaki, Maria, Papagiannopoulos, Nikolaos, Ortiz-Amezcua, Pablo, Mamouri, Rodanthi E., Groß, Silke, Papanikolaou, Christina A., and Kokkalis, Panagiotis

Subjects
BACKSCATTERING, QUANTITATIVE research, BIOMASS burning, AEROSOLS, LIDAR
Abstract

Four years (2014-2017) of observations of depolarization Raman Lidar systems of four EARLINET (European Aerosol research Lidar Network) stations [from West to East: Granada (Spain), Potenza (Italy), Athens (Greece) and Limassol (Cyprus)] were collected and used to a statistical analysis of Saharan dust events over Mediterranean basin. In this study, emphasis is given to the consistency of the particle linear depolarization ratio (δp532), the extinction-to-backscatter ratio mentioned as Lidar Ratio (LR532) and the Aerosol Optical Thickness (AOT532) within the observed Saharan dust layers, corresponding to the visible range (532 nm). Geometrical properties and clusters of aerosol mixtures are also presented. Our clustering was based on previous classification by airborne High Spectral Resolution Lidar (HSRL) observations and was further supported by backward trajectory analysis. We found mean δp532 values of 0.24±0.05, 0.26±0.06, 0.28±0.05 and 0.28±0.04, mean LR532 values of 52±8 sr, 51±9 sr, 52±9 sr and 49±6 sr, mean AOT532 values of 0.40±0.31, 0.11±0.07, 0.12±0.10 and 0.32±0.17 and mean layer thicknesses of 3392±1458 m, 2150±1082 m, 1872±816 m and 1716±567 m for Granada, Potenza, Athens and Limassol respectively. This work could assist in bridging the existing gaps related to the extensive and intensive dust aerosol properties over the Mediterranean and enriching the bibliography about mixed aerosol layers from different sources (e.g. dust and biomass burning (BB) aerosols, dust and urban/ industrial aerosols). [ABSTRACT FROM AUTHOR]

Published
2020
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28. ATHLI16: THE ATHENS LIDAR INTERCOMPARISON CAMPAIGN

Author

Amodeo, Aldo D'Amico, Giuseppe Giunta, Aldo and Papagiannopoulos, Nikolaos Papayannis, Alex Argyrouli, Athina and Mylonaki, Maria Tsaknakis, Georgios Kokkalis, Panos and Soupiona, Ourania Tzanis, Chris

Abstract

The results of the ATHLI16 (ATHens Lidar Intercomparison) campaign, held in Athens from 26/09 to 07/10 2016 are presented. The campaign was performed within the Lidar Calibration Centre activities (EU H2020 ACTRIS-2 project) to assess the performance of the EOLE lidar system (NTUA, Athens, Greece), operating within EARLINET, by comparing against the EARLINET reference lidar system MUSA (CNR-IMAA, Potenza, Italy). For both lidars only products retrieved by the EARLINET Single Calculus Chain have been compared.

Published
2018

29. Tropospheric and stratospheric smoke over Europe as observed within EARLINET/ACTRIS in summer 2017

Author

Baars, Holger, Acheson, Karen, Althausen, Dietrich, Amiridis, Vassilis, Amodeo, Aldo, Ansmann, Albert, Apituley, Arnoud, Alados Arboledas, Lucal, Baldasano, José M., Baray, Jean-Luc, Barragán, Rubén, Belegante, Livio, Antonio Benavent-Oltra, Jose, Bortoli, Daniele, Bühl, Johannes, Comeron, Adolfo, Córdoba, Carmen, D'Amico, Guiseppe, Aguila, Ana del, Dionisi, Davide, Ene, Dragos, Engelmann, Ronny, Fernández García, Alfonso Javier, Fréville, Patrick, Gausa, Michael, Gialitaki, Anna, Goloub, Philippe, Grigorov, Ivan, Guerrero-Rascado, Jean Luis, Haarig, Moritz, Haefele, Alexander, Haeffelin, Martial, Hanuš, Vlastimil, Heese, Birgit, Hervo, Maxime, Hofer, Julian, Hu, Qiaoyun, Iarlori, Marco, Jimenez, Cristofer, Liberti, Gianluigi, Marinou, Eleni, Martucci, Giovanni, Mattis, Ina, Mona, Lucia, Montoux, Nadège, Müller, Detlef, Mylonaki, Maria, Nicolae, Doina, Ortiz-Amezcua, Pablo, Papagiannopoulos, Nikos, Papayannis, Alex, Perrone, Maria Rita, Pietras, Christophe, Pietruczuk, Aleksander, Podvin, Thierry, Popovici, Ioana, Proestakis, Emmanouil, Radenz, Martin, Romano, Salvatore, Schechner, Yoav, Seifert, Patric, Sicard, Michael, Skupin, Annett, Soupiona, Ourania, Stachlewska, Iwona S., Tetoni, Eleni, Trickl, Thomas, Vesselovski, Igor, Vladimir, Zdimal, Vogelmann, Hannes, and Wandinger, Ulla

Subjects
Earth sciences, EARLINET, stratospheric smoke, ddc:550, ACTRIS, lidar
Abstract

For several weeks in summer 2017, strong smoke layers were observed over Europe at numerous EARLINET stations. EARLINET is the European research lidar network and part of ACTRIS and comprises more than 30 ground-based lidars. The smoke layers were observed in the troposphere as well as in the stratosphere up to 25 km from Northern Scandinavia over whole western and central Europe to the Mediterranean regions. Backward trajectory analysis among other tools revealed that these smoke layers originated from strong wild fires in western Canada in combination with pyrocumulus convection. An extraordinary fire event in the mid of August caused intense smoke layers that were observed across Europe for several weeks starting on 18 August 2017. Maximum aerosol optical depths up to 1.0 at 532 nm were observed at Leipzig, Germany, on 22 August 2017 during the peak of this event. The stratospheric smoke layers reached extinction coefficient values of more than 600 Mm−1 at 532 nm, a factor of 10 higher than observed for volcanic ash after the Pinatubo eruption in the 1990s. First analyses of the intensive optical properties revealed low particle depolarization values at 532 nm for the tropospheric smoke (spherical particles) and rather high values (up to 20%) in the stratosphere. However, a strong wavelength dependence of the depolarization ratio was measured for the stratospheric smoke. This indicates irregularly shaped stratospheric smoke particles in the size range of the accumulation mode. This unique depolarization feature makes it possible to distinguish clearly smoke aerosol from cirrus clouds or other aerosol types by polarization lidar measurements. Particle extinction-to-backscatter ratios were rather low in the order of 40 to 50 sr at 355 nm, while values between 70-90 sr were measured at higher wavelengths. In the western and central Mediterranean, stratospheric smoke layers were most prominent in the end of August at heights between 16 and 20 km. In contrast, stratospheric smoke started to occur in the eastern Mediterranean (Cyprus and Israel) in the beginning of September between 18 and 23 km. Stratospheric smoke was still visible in the beginning of October at certain locations (e.g. Evora, Portugal), while tropospheric smoke was mainly observed until the end of August within Europe. An overview of the smoke layers measured at several EARLINET sites will be given. The temporal development of these layers as well as their geometrical and optical properties will be presented.

Published
2018
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30. The unprecedented 2017–2018 stratospheric smoke event: Decay phase and aerosol properties observed with EARLINET

Author

Baars, Holger, primary, Ansmann, Albert, additional, Ohneiser, Kevin, additional, Haarig, Moritz, additional, Engelmann, Ronny, additional, Althausen, Dietrich, additional, Hanssen, Ingrid, additional, Gausa, Michael, additional, Pietruczuk, Aleksander, additional, Szkop, Artur, additional, Stachlewska, Iwona S., additional, Wang, Dongxiang, additional, Reichhardt, Jens, additional, Skupin, Annett, additional, Mattis, Ina, additional, Trickl, Thomas, additional, Vogelmann, Hannes, additional, Navas-Guzmán, Francisco, additional, Haefele, Alexander, additional, Acheson, Karen, additional, Ruth, Albert A., additional, Tatarov, Boyan, additional, Müller, Detlef, additional, Hu, Qiaoyun, additional, Podvin, Thierry, additional, Goloub, Philippe, additional, Vesselovski, Igor, additional, Pietras, Christophe, additional, Haeffelin, Martial, additional, Fréville, Patrick, additional, Sicard, Michaël, additional, Comerón, Adolfo, additional, Fernández García, Alfonso Javier, additional, Molero Menéndez, Francisco, additional, Córdoba-Jabonero, Carmen, additional, Guerrero-Rascado, Juan Luis, additional, Alados-Arboledas, Lucas, additional, Bortoli, Daniele, additional, Costa, Maria João, additional, Dionisi, Davide, additional, Liberti, Gian Luigi, additional, Wang, Xuan, additional, Sannino, Alessia, additional, Papagiannopoulos, Nikolaos, additional, Boselli, Antonella, additional, Mona, Lucia, additional, D'Amico, Giuseppe, additional, Romano, Salvatore, additional, Perrone, Maria Rita, additional, Belegante, Livio, additional, Nicolae, Doina, additional, Grigorov, Ivan, additional, Gialitaki, Anna, additional, Amiridis, Vassilis, additional, Soupiona, Ourania, additional, Papayannis, Alexandros, additional, Mamouri, Rodanthi-Elisaveth, additional, Nisantzi, Argyro, additional, Heese, Birgit, additional, Hofer, Julian, additional, Schechner, Yoav Y., additional, Wandinger, Ulla, additional, and Pappalardo, Gelsomina, additional

Published
2019
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31. Aerosol type classification analysis using EARLINET multiwavelength and depolarization lidar observations.

Author

Mylonaki, Maria, Giannakaki, Elina, Papayannis, Alexandros, Papanikolaou, Christina-Anna, Komppula, Mika, Nicolae, Doina, Papagiannopoulos, Nikolaos, Amodeo, Aldo, Baars, Holger, and Soupiona, Ourania

Abstract

We introduce an automated aerosol type classification method, called Source Classification ANalysis (SCAN). SCAN is based on predefined and characterized aerosol source regions, the time that the air parcel spends above each geographical region and a number of additional criteria. The output of SCAN is compared with two independent aerosol classification methods, which use the intensive optical parameters from lidar data: (1) Mahalanobis distance automatic aerosol type classification (MD) and (2) Neural Network Aerosol Typing Algorithm (NATALI). In this paper, data from the European Aerosol Research Lidar Network (EARLINET) have been used. A total of 97 free tropospheric (FT) aerosol layers from 4 typical EARLINET stations (i.e., Bucharest, Kuopio, Leipzig and Potenza) in the period 2014-2018 were classified based on a 3β+2α+1δ lidar configuration. We found that SCAN, being an optical property independent method, is not affected by the overlapping optical values of different aerosol types. Furthermore, SCAN has no limitations concerning its ability to classify different aerosol mixtures. Additionally, it is a valuable tool to classify aerosol layers, based on even to single (elastic) lidar signals, in case of lidar stations which cannot provide a full data set (3β+2α+1δ) of aerosol optical properties, therefore it can work independently of the capabilities of a lidar system. Finally, our results show that NATALI has the lower percentage of unclassified layers (4 %), while MD has the percentage of unclassified layers (50 %) and the lower percentage of cases classified as aerosol mixtures (5 %). [ABSTRACT FROM AUTHOR]

Published
2020
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32. Saharan dust intrusions over the northern Mediterranean region in the frame of EARLINET (2014-2017): Properties and impact in radiative forcing.

Author

Soupiona, Ourania, Papayannis, Alexandros, Kokkalis, Panagiotis, Foskinis, Romanos, Hernández, Guadalupe Sánchez, Ortiz-Amezcua, Pablo, Mylonaki, Maria, Papanikolaou, Christina-Anna, Papagiannopoulos, Nikolaos, Samaras, Stefanos, Groß, Silke, Mamouri, Rodanthi-Elisavet, Alados-Arboledas, Lucas, Amodeo, Aldo, and Psiloglou, Basil

Abstract

Remote sensing measurements of aerosols using depolarization Raman Lidar systems from 4 EARLINET (European Aerosol research Lidar Network) stations are used for a comprehensive analysis of Saharan dust events over the Mediterranean basin in the period 2014-2017. In this period, we selected to study 51 dust events regarding the geometrical, optical and microphysical properties of dust particles, classifying them and assessing their radiative forcing effect on the atmosphere. From West to East, the stations of Granada, Potenza, Athens and Limassol were selected as representative Mediterranean cities regularly affected by Saharan dust intrusions. Emphasis was given on lidar measurements in the visible (532 nm) and specifically on the consistency of the particle linear depolarization ratio (dp532), the extinction-to-backscatter lidar ratio (LR532) and the Aerosol Optical Thickness (AOT532) within the observed dust layers. We found mean dp532 values of 0.24 ± 0.05, 0.26 ± 0.06, 0.28 ± 0.05 and 0.28 ± 0.04, mean LR532 values of 52 ± 8 sr, 51 ± 9 sr, 52 ± 9 sr and 49 ± 6 sr, and mean AOT532 values of 0.40 ± 0.31, 0.11 ± 0.07, 0.12 ± 0.10 and 0.32 ± 0.17, for Granada, Potenza, Athens and Limassol, respectively. The mean layer thickness values were found to range from ~1700 to ~3400 m. Additionally, based also on a previous aerosol type classification scheme provided by airborne High Spectral Resolution Lidar (HSRL) observations and on air mass backward trajectory analysis, a clustering analysis was performed in order to identify the major mixing aerosol types over the studied area. Furthermore, a synergy of lidar measurements and modeling was used to deeply analyze the solar and thermal radiative forcing of airborne dust. In total, a cooling behavior in the solar range and a significantly lower heating behavior in the thermal range was estimated. Depending on the dust optical and geometrical properties, the load intensity and the solar zenith angle (SZA), the estimated solar radiative forcing values range from -59 to -22 W m-2 at the surface and from -24 to -1 W m-2 at the top of the atmosphere (TOA). Similarly, in the thermal spectral range these values range from +2 to +4 W m-2 for the surface and from +1 to +3 W m-2 for the TOA. Finally, the radiative forcing seems to be inversely proportional to the dust mixing ratio, since higher absolute values are estimated for less mixed dust layers. [ABSTRACT FROM AUTHOR]

Published
2020
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33. Synergetic observations by ground-based and space lidar systems and aeronet sun-radiometers: a step to advanced regional monitoring of large scale aerosol changes

Author

Anton Lopatin, Nikolaos Papagiannopoulos, Nguyen Xuan Anh, Antonela Boselli, Iwona S. Stachlewska, Dimitris Balis, Teppei J. Yasunari, Vladislau Peshcharankou, Tatyana Lapyonok, Leonid Sverdlik, Hitoshi Irie, Aleksander Pietruczuk, Natallia Miatselskaya, Alessia Sannino, Francesc Rocadenbosch, Ina Mattis, Qiaoyun Hu, Andrey Bril, Pham Xuan Thanh, Daniele Bortoli, Ioana Elisabeta Popovici, Aldo Giunta, Dietrich Althausen, Horatiu Stefanie, Nicolae Ajtai, Maria Rita Perrone, Ourania Soupiona, Sang-Woo Kim, Anton Fedarenka, Doina Nicolae, Benjamin Torres, Rei Kudo, Alejandro Rodríguez-Gómez, Roberto Román, Oleg Dubovik, Dong Liu, Atsushi Shimizu, Nobuo Sugimoto, Salvatore Romano, A.J. Fernández, Lucas Alados-Arboledas, Dragos Ene, Thierry Podvin, Tomoaki Nishizawa, Alexandra Tsekeri, Zhengqiang Li, Nikolaos Siomos, Livio Belegante, Philippe Goloub, Michaël Sicard, Juan Luis Guerrero Rascado, Maria Mylonaki, Holger Baars, Toshihiko Takemura, David Fuertes, José Antonio Benavent Oltra, Yurii S. Balin, Maria João Costa, Lucia Mona, Francisco Molero, Itaru Sano, Xuan Wang, Grigorii P. Kokhanenko, Vassilis Amiridis, Genadi Milinevsky, Kalliopi-Artemis Voudouri, Anatoli Chaikovsky, Pablo Ortiz-Amezcua, Andrés Esteban Bedoya-Velásquez, Boris Chen, Ivan Penner, Universitat Politècnica de Catalunya. Departament de Teoria del Senyal i Comunicacions, Universitat Politècnica de Catalunya. RSLAB - Grup de Recerca en Teledetecció, Chaikovsky, Anatoli, Bril, Andrey, Dubovik, Oleg, Fedarenka, Anton, Goloub, Philippe, Hu, Qiaoyun, Lopatin, Anton, Lapyonok, Tatyana, Miatselskaya, Natallia, Torres, Benjamin, Fuertes, David, Peshcharankou, Vladislau, Podvin, Thierry, Popovici, Ioana, Liu, Dong, Li, Zhengqiang, Soupiona, Ourania, Mylonaki, Maria, Mona, Lucia, Giunta, Aldo, Papagiannopoulos, Nikolao, Perrone, Maria Rita, Romano, Salvatore, Balis, Dimitri, Siomos, Nikolao, Voudouri, Kalliopi-Artemi, Belegante, Livio, Nicolae, Doina, Ene, Drago, Ajtai, Nicolae, Stefanie, Horatiu, Amiridis, Vassili, Tsekeri, Alexandra, Bortoli, Daniele, Costa, Maria Joao, Mattis, Ina, Rocadenbosch, Francesc, Rodríguez-Gomez, Alejandro, Sicard, Michael, Fernandez, Alfonso J., Molero, Francisco, Althausen, Dietrich, Baars, Holger, Rascado, Juan Luis Guerrero, Ortiz-Amezcua, Pablo, Oltra, José Antonio Benavent, Bedoya-Velásquez, Andrés Esteban, Román, Roberto, Alados-Arboledas, Luca, Balin, Yurii, Kokhanenko, Grigorii, Penner, Ivan, Chen, Bori, Sverdlik, Leonid, Milinevsky, Genadi, Sugimoto, Nobuo, Shimizu, Atsushi, Nishizawa, Tomoaki, Kudo, Rei, Sano, Itaru, Yasunari, Teppei J., Irie, Hitoshi, Takemura, Toshihiko, Kim, Sang-Woo, Anh, Nguyen Xuan, Thanh, Pham Xuan, Pietruczuk, Aleksander, Stachlewska, Iwona S., Sannino, Alessia, Wang, Xuan, and Boselli, Antonela

Subjects
Teledetecció, 010504 meteorology & atmospheric sciences, QC1-999, Optical radar, Aerosols atmosfèrics, 01 natural sciences, 7. Clean energy, Fire smoke, 010309 optics, 0103 physical sciences, 0105 earth and related environmental sciences, Remote sensing, Aerosols, Lidar, Radiometer, Physics, Mode (statistics), Atmospheric aerosols, Radar òptic, Aerosol, AERONET, Enginyeria de la telecomunicació::Radiocomunicació i exploració electromagnètica::Teledetecció [Àrees temàtiques de la UPC], 13. Climate action, Scale (map)
Abstract

The financial support by the European Union's Horizon 2020 research and innovation program (ACTRIS-2, grant agreement no. 654109) is gratefully acknowledged. The investigation was supported by the Belarusian Republican Foundation for Fundamental, Research Agreement No. F18EA-011, by the Russian Foundation for Basic Research (grant No. 18-55-81001), and also by Vietnam Academy of Science and Technology (project code QTRU05.01/18-20). The Portuguese team acknowledges the support from the Portuguese Science Foundation, in the frame of the European Regional Development Fund -COMPETE 2020, under the projects UID/GEO/04683/2013 (POCI-01-0145-FEDER-007690), The paper presents the preliminary results of the lidar&radiometer measurement campaign (LRMC2017), estimation of statistical relations between aerosol mode concentrations retrieved from CALIOP and ground-based lidar stations and case study of fire smoke events in the Eurasian regions using combined ground-based and space lidar and radiometer observations., European Union's Horizon 2020 research and innovation program (ACTRIS-2) 654109, Belarusian Republican Foundation for Fundamental, Research F18EA-011, Russian Foundation for Basic Research (RFBR) 18-55-81001, Vietnam Academy of Science and Technology QTRU05.01/18-20, Portuguese Science Foundation, in the frame of the European Regional Development Fund -COMPETE 2020 UID/GEO/04683/2013 (POCI-01-0145-FEDER-007690)

Published
2020
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34. The unprecedented 2017–2018 stratospheric smoke event: decay phase and aerosol properties observed with the EARLINET

Author

Holger Baars, Albert Ansmann, Kevin Ohneiser, Moritz Haarig, Ronny Engelmann, Dietrich Althausen, Ingrid Hanssen, Michael Gausa, Aleksander Pietruczuk, Artur Szkop, Iwona S. Stachlewska, Dongxiang Wang, Jens Reichhardt, Annett Skupin, Ina Mattis, Thomas Trickl, Hannes Vogelmann, Francisco Navas-Guzmán, Alexander Haefele, Karen Acheson, Albert A. Ruth, Boyan Tatarov, Detlef Müller, Qiaoyun Hu, Thierry Podvin, Philippe Goloub, Igor Vesselovski, Christophe Pietras, Martial Haeffelin, Patrick Fréville, Michaël Sicard, Adolfo Comerón, Alfonso Javier Fernández García, Francisco Molero Menéndez, Carmen Córdoba-Jabonero, Juan Luis Guerrero-Rascado, Lucas Alados-Arboledas, Daniele Bortoli, Maria João Costa, Davide Dionisi, Gian Luigi Liberti, Xuan Wang, Alessia Sannino, Nikolaos Papagiannopoulos, Antonella Boselli, Lucia Mona, Giuseppe D'Amico, Salvatore Romano, Maria Rita Perrone, Livio Belegante, Doina Nicolae, Ivan Grigorov, Anna Gialitaki, Vassilis Amiridis, Ourania Soupiona, Alexandros Papayannis, Rodanthi-Elisaveth Mamouri, Argyro Nisantzi, Birgit Heese, Julian Hofer, Yoav Y. Schechner, Ulla Wandinger, Gelsomina Pappalardo, Laboratoire d’Optique Atmosphérique - UMR 8518 (LOA), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Baars, Holger, Ansmann, Albert, Ohneiser, Kevin, Haarig, Moritz, Engelmann, Ronny, Althausen, Dietrich, Hanssen, Ingrid, Gausa, Michael, Pietruczuk, Aleksander, Szkop, Artur, Stachlewska, Iwona S., Wang, Dongxiang, Reichardt, Jen, Skupin, Annett, Mattis, Ina, Trickl, Thoma, Vogelmann, Hanne, Navas-Guzmán, Francisco, Haefele, Alexander, Acheson, Karen, Ruth, Albert A., Tatarov, Boyan, Müller, Detlef, Hu, Qiaoyun, Podvin, Thierry, Goloub, Philippe, Veselovskii, Igor, Pietras, Christophe, Haeffelin, Martial, Fréville, Patrick, Sicard, Michaël, Comerón, Adolfo, Fernández García, Alfonso Javier, Molero Menéndez, Francisco, Córdoba-Jabonero, Carmen, Guerrero-Rascado, Juan Lui, Alados-Arboledas, Luca, Bortoli, Daniele, Costa, Maria João, Dionisi, Davide, Liberti, Gian Luigi, Wang, Xuan, Sannino, Alessia, Papagiannopoulos, Nikolao, Boselli, Antonella, Mona, Lucia, D'Amico, Giuseppe, Romano, Salvatore, Perrone, Maria Rita, Belegante, Livio, Nicolae, Doina, Grigorov, Ivan, Gialitaki, Anna, Amiridis, Vassili, Soupiona, Ourania, Papayannis, Alexandro, Mamouri, Rodanthi-Elisaveth, Nisantzi, Argyro, Heese, Birgit, Hofer, Julian, Schechner, Yoav Y., Wandinger, Ulla, and Pappalardo, Gelsomina

Subjects
aerosol property, Stratospheric aerosol observations, black carbon, atmospheric plume, soot, Remote Sensing, Black carbon, Soot, Smoke, INP concentrations, Brewer-Dobson circulation system, Northern Hemisphere, Wild fire smoke, Aerosols, Lidar, Stratosphere, European Aerosol Research Lidar Network (EARLINET), Troposphere, Atmospheric plume, Smoke layer, smoke, troposphere, [SDU]Sciences of the Universe [physics], stratosphere, Earth and Related Environmental Sciences, Natural Sciences, Aerosol property
Abstract

International audience; Six months of stratospheric aerosol observations with the European Aerosol Research Lidar Network (EARLINET) from August 2017 to January 2018 are presented. The decay phase of an unprecedented, record-breaking stratospheric perturbation caused by wildfire smoke is reported and discussed in terms of geometrical, optical, and microphysical aerosol properties. Enormous amounts of smoke were injected into the upper troposphere and lower stratosphere over fire areas in western Canada on 12 August 2017 during strong thunderstorm-pyrocumulonimbus activity. The stratospheric fire plumes spread over the entire Northern Hemisphere in the following weeks and months. Twenty-eight European lidar stations from northern Norway to southern Portugal and the eastern Mediterranean monitored the strong stratospheric perturbation on a continental scale. The main smoke layer (over central, western, southern, and eastern Europe) was found at heights between 15 and 20 km since September 2017 (about 2 weeks after entering the stratosphere). Thin layers of smoke were detected at heights of up to 22-23 km. The stratospheric aerosol optical thickness at 532 nm decreased from values > 0.25 on 21-23 August 2017 to 0.005-0.03 until 5-10 September and was mainly 0.003-0.004 from October to December 2017 and thus was still significantly above the stratospheric background (0.001-0.002). Stratospheric particle extinction coefficients (532 nm) were as high as 50-200 Mm-1 until the beginning of September and on the order of 1 Mm-1 (0.5-5 Mm-1) from October 2017 until the end of January 2018. The corresponding layer mean particle mass concentration was on the order of 0.05-0.5 µg m-3 over these months. Soot particles (light-absorbing carbonaceous particles) are efficient ice-nucleating particles (INPs) at upper tropospheric (cirrus) temperatures and available to influence cirrus formation when entering the tropopause from above. We estimated INP concentrations of 50-500 L-1 until the first days in September and afterwards 5-50 L-1 until the end of the year 2017 in the lower stratosphere for typical cirrus formation temperatures of -55 ∘C and an ice supersaturation level of 1.15. The measured profiles of the particle linear depolarization ratio indicated a predominance of nonspherical smoke particles. The 532 nm depolarization ratio decreased slowly with time in the main smoke layer from values of 0.15-0.25 (August-September) to values of 0.05-0.10 (October-November) and < 0.05 (December-January). The decrease of the depolarization ratio is consistent with aging of the smoke particles, growing of a coating around the solid black carbon core (aggregates), and thus change of the shape towards a spherical form. We found ascending aerosol layer features over the most southern European stations, especially over the eastern Mediterranean at 32-35∘ N, that ascended from heights of about 18-19 to 22-23 km from the beginning of October to the beginning of December 2017 (about 2 km per month). We discuss several transport and lifting mechanisms that may have had an impact on the found aerosol layering structures.

Published
2019

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