Absorption instruments inter-comparison campaign at the Arctic Pallas station
Aerosol light absorption was measured during a 1-month field campaign in June-July 2019 at the Pallas Global Atmospheric Watch (GAW) station in northern Finland. Very low aerosol concentrations prevailed during the campaign, which posed a challenge for the instruments' detection capabilities. T...
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2021
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ftdatacite:10.34657/7281 2023-05-15T15:08:00+02:00 Absorption instruments inter-comparison campaign at the Arctic Pallas station Asmi, Eija Backman, John Servomaa, Henri Virkkula, Aki Gini, Maria I. Eleftheriadis, Konstantinos Müller, Thomas Ohata, Sho Kondo, Yutaka Hyvärinen, Antti 2021 https://dx.doi.org/10.34657/7281 https://oa.tib.eu/renate/handle/123456789/8243 en eng Katlenburg-Lindau : European Geosciences Union Creative Commons Attribution 4.0 International CC BY 4.0 Unported https://creativecommons.org/licenses/by/4.0/legalcode cc-by-4.0 CC-BY absorption coefficient aerosol concentration composition COSMOS cross section detection method instrumentation monitoring system wavelength Arctic Finland Lappi [Finland] Pallas 550 article CreativeWork 2021 ftdatacite https://doi.org/10.34657/7281 2022-04-01T18:37:25Z Aerosol light absorption was measured during a 1-month field campaign in June-July 2019 at the Pallas Global Atmospheric Watch (GAW) station in northern Finland. Very low aerosol concentrations prevailed during the campaign, which posed a challenge for the instruments' detection capabilities. The campaign provided a real-world test for different absorption measurement techniques supporting the goals of the European Metrology Programme for Innovation and Research (EMPIR) Black Carbon (BC) project in developing aerosol absorption standard and reference methods. In this study we compare the results from five filter-based absorption techniques - aethalometer models AE31 and AE33, a particle soot absorption photometer (PSAP), a multi-angle absorption photometer (MAAP), and a continuous soot monitoring system (COSMOS) - and from one indirect technique called extinction minus scattering (EMS). The ability of the filter-based techniques was shown to be adequate to measure aerosol light absorption coefficients down to around 0.01g¯Mm-1 levels when data were averaged to 1-2g¯h. The hourly averaged atmospheric absorption measured by the reference MAAP was 0.09g¯Mm-1 (at a wavelength of 637g¯nm). When data were averaged for >1g¯h, the filter-based methods agreed to around 40g¯%. COSMOS systematically measured the lowest absorption coefficient values, which was expected due to the sample pre-treatment in the COSMOS inlet. PSAP showed the best linear correlation with MAAP (slopeCombining double low line0.95, R2Combining double low line0.78), followed by AE31 (slopeCombining double low line0.93). A scattering correction applied to PSAP data improved the data accuracy despite the added noise. However, at very high scattering values the correction led to an underestimation of the absorption. The AE31 data had the highest noise and the correlation with MAAP was the lowest (R2Combining double low line0.65). Statistically the best linear correlations with MAAP were obtained for AE33 and COSMOS (R2 close to 1), but the biases at around the zero values led to slopes clearly below 1. The sample pre-treatment in the COSMOS instrument resulted in the lowest fitted slope. In contrast to the filter-based techniques, the indirect EMS method was not adequate to measure the low absorption values found at the Pallas site. The lowest absorption at which the EMS signal could be distinguished from the noise was >0.1g¯Mm-1 at 1-2g¯h averaging times. The mass absorption cross section (MAC) value measured at a range 0-0.3g¯Mm-1 was calculated using the MAAP and a single particle soot photometer (SP2), resulting in a MAC value of 16.0±5.7g¯m2g-1. Overall, our results demonstrate the challenges encountered in the aerosol absorption measurements in pristine environments and provide some useful guidelines for instrument selection and measurement practices. We highlight the need for a calibrated transfer standard for better inter-comparability of the absorption results. © Author(s) 2021. Article in Journal/Newspaper Arctic black carbon Northern Finland Lappi DataCite Metadata Store (German National Library of Science and Technology) Arctic |
institution |
Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
English |
topic |
absorption coefficient aerosol concentration composition COSMOS cross section detection method instrumentation monitoring system wavelength Arctic Finland Lappi [Finland] Pallas 550 |
spellingShingle |
absorption coefficient aerosol concentration composition COSMOS cross section detection method instrumentation monitoring system wavelength Arctic Finland Lappi [Finland] Pallas 550 Asmi, Eija Backman, John Servomaa, Henri Virkkula, Aki Gini, Maria I. Eleftheriadis, Konstantinos Müller, Thomas Ohata, Sho Kondo, Yutaka Hyvärinen, Antti Absorption instruments inter-comparison campaign at the Arctic Pallas station |
topic_facet |
absorption coefficient aerosol concentration composition COSMOS cross section detection method instrumentation monitoring system wavelength Arctic Finland Lappi [Finland] Pallas 550 |
description |
Aerosol light absorption was measured during a 1-month field campaign in June-July 2019 at the Pallas Global Atmospheric Watch (GAW) station in northern Finland. Very low aerosol concentrations prevailed during the campaign, which posed a challenge for the instruments' detection capabilities. The campaign provided a real-world test for different absorption measurement techniques supporting the goals of the European Metrology Programme for Innovation and Research (EMPIR) Black Carbon (BC) project in developing aerosol absorption standard and reference methods. In this study we compare the results from five filter-based absorption techniques - aethalometer models AE31 and AE33, a particle soot absorption photometer (PSAP), a multi-angle absorption photometer (MAAP), and a continuous soot monitoring system (COSMOS) - and from one indirect technique called extinction minus scattering (EMS). The ability of the filter-based techniques was shown to be adequate to measure aerosol light absorption coefficients down to around 0.01g¯Mm-1 levels when data were averaged to 1-2g¯h. The hourly averaged atmospheric absorption measured by the reference MAAP was 0.09g¯Mm-1 (at a wavelength of 637g¯nm). When data were averaged for >1g¯h, the filter-based methods agreed to around 40g¯%. COSMOS systematically measured the lowest absorption coefficient values, which was expected due to the sample pre-treatment in the COSMOS inlet. PSAP showed the best linear correlation with MAAP (slopeCombining double low line0.95, R2Combining double low line0.78), followed by AE31 (slopeCombining double low line0.93). A scattering correction applied to PSAP data improved the data accuracy despite the added noise. However, at very high scattering values the correction led to an underestimation of the absorption. The AE31 data had the highest noise and the correlation with MAAP was the lowest (R2Combining double low line0.65). Statistically the best linear correlations with MAAP were obtained for AE33 and COSMOS (R2 close to 1), but the biases at around the zero values led to slopes clearly below 1. The sample pre-treatment in the COSMOS instrument resulted in the lowest fitted slope. In contrast to the filter-based techniques, the indirect EMS method was not adequate to measure the low absorption values found at the Pallas site. The lowest absorption at which the EMS signal could be distinguished from the noise was >0.1g¯Mm-1 at 1-2g¯h averaging times. The mass absorption cross section (MAC) value measured at a range 0-0.3g¯Mm-1 was calculated using the MAAP and a single particle soot photometer (SP2), resulting in a MAC value of 16.0±5.7g¯m2g-1. Overall, our results demonstrate the challenges encountered in the aerosol absorption measurements in pristine environments and provide some useful guidelines for instrument selection and measurement practices. We highlight the need for a calibrated transfer standard for better inter-comparability of the absorption results. © Author(s) 2021. |
format |
Article in Journal/Newspaper |
author |
Asmi, Eija Backman, John Servomaa, Henri Virkkula, Aki Gini, Maria I. Eleftheriadis, Konstantinos Müller, Thomas Ohata, Sho Kondo, Yutaka Hyvärinen, Antti |
author_facet |
Asmi, Eija Backman, John Servomaa, Henri Virkkula, Aki Gini, Maria I. Eleftheriadis, Konstantinos Müller, Thomas Ohata, Sho Kondo, Yutaka Hyvärinen, Antti |
author_sort |
Asmi, Eija |
title |
Absorption instruments inter-comparison campaign at the Arctic Pallas station |
title_short |
Absorption instruments inter-comparison campaign at the Arctic Pallas station |
title_full |
Absorption instruments inter-comparison campaign at the Arctic Pallas station |
title_fullStr |
Absorption instruments inter-comparison campaign at the Arctic Pallas station |
title_full_unstemmed |
Absorption instruments inter-comparison campaign at the Arctic Pallas station |
title_sort |
absorption instruments inter-comparison campaign at the arctic pallas station |
publisher |
Katlenburg-Lindau : European Geosciences Union |
publishDate |
2021 |
url |
https://dx.doi.org/10.34657/7281 https://oa.tib.eu/renate/handle/123456789/8243 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic black carbon Northern Finland Lappi |
genre_facet |
Arctic black carbon Northern Finland Lappi |
op_rights |
Creative Commons Attribution 4.0 International CC BY 4.0 Unported https://creativecommons.org/licenses/by/4.0/legalcode cc-by-4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.34657/7281 |
_version_ |
1766339432264237056 |