In situ measurements of aerosol optical properties and number size distributions in a coastal region of Norway during the summer of 2008
Abstract. In situ measurements of aerosol optical properties and particle size distributions were made in the summer of 2008 at the ALOMAR station facility (69◦160 N, 16◦ 000 E), located in a rural site in the north of the island of Andøya (Vesterålen archipelago), approximately 300 km north of the...
Published in: | Atmospheric Chemistry and Physics |
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Main Authors: | , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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2018
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Online Access: | http://hdl.handle.net/10400.6/5773 https://doi.org/10.5194/acp-12-5841-2012 |
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ftunivbeirainter:oai:ubibliorum.ubi.pt:10400.6/5773 |
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Open Polar |
collection |
Universidade da Beira Interior: Ubi Thesis - Conhecimento Online |
op_collection_id |
ftunivbeirainter |
language |
English |
topic |
Aerosols Optical properties Size distribution Arctic |
spellingShingle |
Aerosols Optical properties Size distribution Arctic Mogo, Sandra Cachorro, Victoria Lopez, J. F. Montilla, E. Torres, B. Rodríguez, E. Bennouna, Y. de Frutos, Ángel M In situ measurements of aerosol optical properties and number size distributions in a coastal region of Norway during the summer of 2008 |
topic_facet |
Aerosols Optical properties Size distribution Arctic |
description |
Abstract. In situ measurements of aerosol optical properties and particle size distributions were made in the summer of 2008 at the ALOMAR station facility (69◦160 N, 16◦ 000 E), located in a rural site in the north of the island of Andøya (Vesterålen archipelago), approximately 300 km north of the Arctic Circle. The extended three-month campaign was part of the POLARCAT Project (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) of the International Polar Year (IPY-2007-2008). Our goal was to characterize the aerosols of this sub-Arctic area, which are frequently transported to the Arctic region. Data from 13 June to 26 August 2008 were available and the statistical data for all instruments were calculated based on the hourly averages. The overall data coverage was approximately 72 %. The hourly mean values of the light-scattering coefficient, σs , and the light-absorption coefficient, σa, at 550 nm were 5.41 Mm−1 (StD = 3.55 Mm−1 ) and 0.40 Mm−1 (StD = 0.27 Mm−1 ), respectively. The scattering/absorption Ångström exponents, αs,a , were used in a detailed analysis of the variations of the spectral shape of σs,a. While αs indicates the presence of two particle sizes corresponding to two types of aerosols, αa indicates only one type of absorbing aerosol particle. αa values greater than 1 were not observed. The single-scattering albedo, ω0 , ranged from 0.62 to 0.99 (mean = 0.91, StD = 0.05), and the relationships between this parameter and the absorption/scattering coefficients and the Ångström exponents are presented. Any absorption value may lead to the lowest values of ω0 , whereas only the lowest scattering values were observed in the lowest range of ω0 . For a given absorption value, lower ω0 were observed for smaller αs. The submicrometer, micrometer and total concentrations of the particles presented hourly mean values of 1277 cm−3 (StD = 1563 cm−3), 1 cm−3 (StD = 1 cm−3) and 2463 cm−3 (StD = 4251 cm−3), respectively, and the modal correlations were also investigated. The optical and microphysical parameters, as well as their relationship with each other, are reported. σs correlated strongly with the number concentration of accumulation mode particles and more strongly with the micrometer fraction of particles, but weak correlations were observed for the Aitken and nucleation modes. The origins and pathways of the air masses were examined, and based on sector classification, a relationship between the air mass origin, the optical parameters and the size distributions was established. The low values of the optical and microphysical parameters indicate that the predominant regional aerosol is mostly clean and the shape of the size distribution is characterized by bimodal median size distributions. However, the relationships between the air mass origins and the parameters studied allow us to describe two characteristic situations: the one of the northern and western air masses, which were predominantly composed of marine aerosols and presented the lowest optical and microphysical values observed, indicating predominantly non-absorbent and coarser particles; and the one of the eastern and southern air masses, in which continental aerosols were predominant and exhibited higher values for all parameters, indicating the presence of smaller absorbent particles. The north-northeastern air masses presented the strongest Aitken mode, indicating more recently formed particles, and the southeastern air masses presented the strongest accumulation mode (however, the southeastern air masses were the least common, accounting for only 3 % of occurrences). info:eu-repo/semantics/publishedVersion |
format |
Article in Journal/Newspaper |
author |
Mogo, Sandra Cachorro, Victoria Lopez, J. F. Montilla, E. Torres, B. Rodríguez, E. Bennouna, Y. de Frutos, Ángel M |
author_facet |
Mogo, Sandra Cachorro, Victoria Lopez, J. F. Montilla, E. Torres, B. Rodríguez, E. Bennouna, Y. de Frutos, Ángel M |
author_sort |
Mogo, Sandra |
title |
In situ measurements of aerosol optical properties and number size distributions in a coastal region of Norway during the summer of 2008 |
title_short |
In situ measurements of aerosol optical properties and number size distributions in a coastal region of Norway during the summer of 2008 |
title_full |
In situ measurements of aerosol optical properties and number size distributions in a coastal region of Norway during the summer of 2008 |
title_fullStr |
In situ measurements of aerosol optical properties and number size distributions in a coastal region of Norway during the summer of 2008 |
title_full_unstemmed |
In situ measurements of aerosol optical properties and number size distributions in a coastal region of Norway during the summer of 2008 |
title_sort |
in situ measurements of aerosol optical properties and number size distributions in a coastal region of norway during the summer of 2008 |
publishDate |
2018 |
url |
http://hdl.handle.net/10400.6/5773 https://doi.org/10.5194/acp-12-5841-2012 |
long_lat |
ENVELOPE(-44.516,-44.516,-60.733,-60.733) ENVELOPE(-67.083,-67.083,-68.133,-68.133) ENVELOPE(13.982,13.982,68.185,68.185) |
geographic |
Aitken Alomar Andøya Arctic Norway |
geographic_facet |
Aitken Alomar Andøya Arctic Norway |
genre |
albedo Andøya Arctic International Polar Year IPY |
genre_facet |
albedo Andøya Arctic International Polar Year IPY |
op_relation |
http://hdl.handle.net/10400.6/5773 doi:10.5194/acp-12-5841-2012 |
op_rights |
openAccess |
op_doi |
https://doi.org/10.5194/acp-12-5841-2012 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
12 |
container_issue |
13 |
container_start_page |
5841 |
op_container_end_page |
5857 |
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1766249760028622848 |
spelling |
ftunivbeirainter:oai:ubibliorum.ubi.pt:10400.6/5773 2023-05-15T13:11:58+02:00 In situ measurements of aerosol optical properties and number size distributions in a coastal region of Norway during the summer of 2008 Mogo, Sandra Cachorro, Victoria Lopez, J. F. Montilla, E. Torres, B. Rodríguez, E. Bennouna, Y. de Frutos, Ángel M 2018-08-27T15:58:48Z http://hdl.handle.net/10400.6/5773 https://doi.org/10.5194/acp-12-5841-2012 eng eng http://hdl.handle.net/10400.6/5773 doi:10.5194/acp-12-5841-2012 openAccess Aerosols Optical properties Size distribution Arctic article 2018 ftunivbeirainter https://doi.org/10.5194/acp-12-5841-2012 2022-05-01T13:57:18Z Abstract. In situ measurements of aerosol optical properties and particle size distributions were made in the summer of 2008 at the ALOMAR station facility (69◦160 N, 16◦ 000 E), located in a rural site in the north of the island of Andøya (Vesterålen archipelago), approximately 300 km north of the Arctic Circle. The extended three-month campaign was part of the POLARCAT Project (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) of the International Polar Year (IPY-2007-2008). Our goal was to characterize the aerosols of this sub-Arctic area, which are frequently transported to the Arctic region. Data from 13 June to 26 August 2008 were available and the statistical data for all instruments were calculated based on the hourly averages. The overall data coverage was approximately 72 %. The hourly mean values of the light-scattering coefficient, σs , and the light-absorption coefficient, σa, at 550 nm were 5.41 Mm−1 (StD = 3.55 Mm−1 ) and 0.40 Mm−1 (StD = 0.27 Mm−1 ), respectively. The scattering/absorption Ångström exponents, αs,a , were used in a detailed analysis of the variations of the spectral shape of σs,a. While αs indicates the presence of two particle sizes corresponding to two types of aerosols, αa indicates only one type of absorbing aerosol particle. αa values greater than 1 were not observed. The single-scattering albedo, ω0 , ranged from 0.62 to 0.99 (mean = 0.91, StD = 0.05), and the relationships between this parameter and the absorption/scattering coefficients and the Ångström exponents are presented. Any absorption value may lead to the lowest values of ω0 , whereas only the lowest scattering values were observed in the lowest range of ω0 . For a given absorption value, lower ω0 were observed for smaller αs. The submicrometer, micrometer and total concentrations of the particles presented hourly mean values of 1277 cm−3 (StD = 1563 cm−3), 1 cm−3 (StD = 1 cm−3) and 2463 cm−3 (StD = 4251 cm−3), respectively, and the modal correlations were also investigated. The optical and microphysical parameters, as well as their relationship with each other, are reported. σs correlated strongly with the number concentration of accumulation mode particles and more strongly with the micrometer fraction of particles, but weak correlations were observed for the Aitken and nucleation modes. The origins and pathways of the air masses were examined, and based on sector classification, a relationship between the air mass origin, the optical parameters and the size distributions was established. The low values of the optical and microphysical parameters indicate that the predominant regional aerosol is mostly clean and the shape of the size distribution is characterized by bimodal median size distributions. However, the relationships between the air mass origins and the parameters studied allow us to describe two characteristic situations: the one of the northern and western air masses, which were predominantly composed of marine aerosols and presented the lowest optical and microphysical values observed, indicating predominantly non-absorbent and coarser particles; and the one of the eastern and southern air masses, in which continental aerosols were predominant and exhibited higher values for all parameters, indicating the presence of smaller absorbent particles. The north-northeastern air masses presented the strongest Aitken mode, indicating more recently formed particles, and the southeastern air masses presented the strongest accumulation mode (however, the southeastern air masses were the least common, accounting for only 3 % of occurrences). info:eu-repo/semantics/publishedVersion Article in Journal/Newspaper albedo Andøya Arctic International Polar Year IPY Universidade da Beira Interior: Ubi Thesis - Conhecimento Online Aitken ENVELOPE(-44.516,-44.516,-60.733,-60.733) Alomar ENVELOPE(-67.083,-67.083,-68.133,-68.133) Andøya ENVELOPE(13.982,13.982,68.185,68.185) Arctic Norway Atmospheric Chemistry and Physics 12 13 5841 5857 |