Temporal and spectral cloud screening of polar winter aerosol optical depth (AOD): impact of homogeneous and inhomogeneous clouds and crystal layers on climatological-scale AODs
We compared star-photometry-derived, polar winter aerosol optical depths (AODs), acquired at Eureka, Nunavut, Canada, and Ny-Ålesund, Svalbard, with GEOS-Chem (GC) simulations as well as ground-based lidar and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) retrievals over a sampling perio...
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ftdoajarticles:oai:doaj.org/article:9bf206b6eb8a42a39facdd06381c58c4 2023-05-15T16:08:36+02:00 Temporal and spectral cloud screening of polar winter aerosol optical depth (AOD): impact of homogeneous and inhomogeneous clouds and crystal layers on climatological-scale AODs N. T. O'Neill K. Baibakov S. Hesaraki L. Ivanescu R. V. Martin C. Perro J. P. Chaubey A. Herber T. J. Duck 2016-10-01T00:00:00Z https://doi.org/10.5194/acp-16-12753-2016 https://doaj.org/article/9bf206b6eb8a42a39facdd06381c58c4 EN eng Copernicus Publications https://www.atmos-chem-phys.net/16/12753/2016/acp-16-12753-2016.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-16-12753-2016 1680-7316 1680-7324 https://doaj.org/article/9bf206b6eb8a42a39facdd06381c58c4 Atmospheric Chemistry and Physics, Vol 16, Pp 12753-12765 (2016) Physics QC1-999 Chemistry QD1-999 article 2016 ftdoajarticles https://doi.org/10.5194/acp-16-12753-2016 2022-12-30T22:09:23Z We compared star-photometry-derived, polar winter aerosol optical depths (AODs), acquired at Eureka, Nunavut, Canada, and Ny-Ålesund, Svalbard, with GEOS-Chem (GC) simulations as well as ground-based lidar and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) retrievals over a sampling period of two polar winters. The results indicate significant cloud and/or low-altitude ice crystal (LIC) contamination which is only partially corrected using temporal cloud screening. Spatially homogeneous clouds and LICs that remain after temporal cloud screening represent an inevitable systematic error in the estimation of AOD: this error was estimated to vary from 78 to 210 % at Eureka and from 2 to 157 % at Ny-Ålesund. Lidar analysis indicated that LICs appeared to have a disproportionately large influence on the homogeneous coarse-mode optical depths that escape temporal cloud screening. In principle, spectral cloud screening (to yield fine-mode or submicron AODs) reduces pre-cloud-screened AODs to the aerosol contribution if one assumes that coarse-mode (super-micron) aerosols are a minor part of the AOD. Large, low-frequency differences between these retrieved values and their GC analogue appeared to be often linked to strong, spatially extensive planetary boundary layer events whose presence at either site was inferred from CALIOP profiles. These events were either not captured or significantly underestimated by the GC simulations. High-frequency AOD variations of GC fine-mode aerosols at Ny-Ålesund were attributed to sea salt, while low-frequency GC variations at Eureka and Ny-Ålesund were attributable to sulfates. CALIOP profiles and AODs were invaluable as spatial and temporal redundancy support (or, alternatively, as insightful points of contention) for star photometry retrievals and GC estimates of AOD. Article in Journal/Newspaper Eureka Nunavut Ny Ålesund Ny-Ålesund Svalbard Directory of Open Access Journals: DOAJ Articles Canada Eureka ENVELOPE(-85.940,-85.940,79.990,79.990) Nunavut Ny-Ålesund Svalbard Atmospheric Chemistry and Physics 16 19 12753 12765 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Physics QC1-999 Chemistry QD1-999 |
spellingShingle |
Physics QC1-999 Chemistry QD1-999 N. T. O'Neill K. Baibakov S. Hesaraki L. Ivanescu R. V. Martin C. Perro J. P. Chaubey A. Herber T. J. Duck Temporal and spectral cloud screening of polar winter aerosol optical depth (AOD): impact of homogeneous and inhomogeneous clouds and crystal layers on climatological-scale AODs |
topic_facet |
Physics QC1-999 Chemistry QD1-999 |
description |
We compared star-photometry-derived, polar winter aerosol optical depths (AODs), acquired at Eureka, Nunavut, Canada, and Ny-Ålesund, Svalbard, with GEOS-Chem (GC) simulations as well as ground-based lidar and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) retrievals over a sampling period of two polar winters. The results indicate significant cloud and/or low-altitude ice crystal (LIC) contamination which is only partially corrected using temporal cloud screening. Spatially homogeneous clouds and LICs that remain after temporal cloud screening represent an inevitable systematic error in the estimation of AOD: this error was estimated to vary from 78 to 210 % at Eureka and from 2 to 157 % at Ny-Ålesund. Lidar analysis indicated that LICs appeared to have a disproportionately large influence on the homogeneous coarse-mode optical depths that escape temporal cloud screening. In principle, spectral cloud screening (to yield fine-mode or submicron AODs) reduces pre-cloud-screened AODs to the aerosol contribution if one assumes that coarse-mode (super-micron) aerosols are a minor part of the AOD. Large, low-frequency differences between these retrieved values and their GC analogue appeared to be often linked to strong, spatially extensive planetary boundary layer events whose presence at either site was inferred from CALIOP profiles. These events were either not captured or significantly underestimated by the GC simulations. High-frequency AOD variations of GC fine-mode aerosols at Ny-Ålesund were attributed to sea salt, while low-frequency GC variations at Eureka and Ny-Ålesund were attributable to sulfates. CALIOP profiles and AODs were invaluable as spatial and temporal redundancy support (or, alternatively, as insightful points of contention) for star photometry retrievals and GC estimates of AOD. |
format |
Article in Journal/Newspaper |
author |
N. T. O'Neill K. Baibakov S. Hesaraki L. Ivanescu R. V. Martin C. Perro J. P. Chaubey A. Herber T. J. Duck |
author_facet |
N. T. O'Neill K. Baibakov S. Hesaraki L. Ivanescu R. V. Martin C. Perro J. P. Chaubey A. Herber T. J. Duck |
author_sort |
N. T. O'Neill |
title |
Temporal and spectral cloud screening of polar winter aerosol optical depth (AOD): impact of homogeneous and inhomogeneous clouds and crystal layers on climatological-scale AODs |
title_short |
Temporal and spectral cloud screening of polar winter aerosol optical depth (AOD): impact of homogeneous and inhomogeneous clouds and crystal layers on climatological-scale AODs |
title_full |
Temporal and spectral cloud screening of polar winter aerosol optical depth (AOD): impact of homogeneous and inhomogeneous clouds and crystal layers on climatological-scale AODs |
title_fullStr |
Temporal and spectral cloud screening of polar winter aerosol optical depth (AOD): impact of homogeneous and inhomogeneous clouds and crystal layers on climatological-scale AODs |
title_full_unstemmed |
Temporal and spectral cloud screening of polar winter aerosol optical depth (AOD): impact of homogeneous and inhomogeneous clouds and crystal layers on climatological-scale AODs |
title_sort |
temporal and spectral cloud screening of polar winter aerosol optical depth (aod): impact of homogeneous and inhomogeneous clouds and crystal layers on climatological-scale aods |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/acp-16-12753-2016 https://doaj.org/article/9bf206b6eb8a42a39facdd06381c58c4 |
long_lat |
ENVELOPE(-85.940,-85.940,79.990,79.990) |
geographic |
Canada Eureka Nunavut Ny-Ålesund Svalbard |
geographic_facet |
Canada Eureka Nunavut Ny-Ålesund Svalbard |
genre |
Eureka Nunavut Ny Ålesund Ny-Ålesund Svalbard |
genre_facet |
Eureka Nunavut Ny Ålesund Ny-Ålesund Svalbard |
op_source |
Atmospheric Chemistry and Physics, Vol 16, Pp 12753-12765 (2016) |
op_relation |
https://www.atmos-chem-phys.net/16/12753/2016/acp-16-12753-2016.pdf https://doaj.org/toc/1680-7316 https://doaj.org/toc/1680-7324 doi:10.5194/acp-16-12753-2016 1680-7316 1680-7324 https://doaj.org/article/9bf206b6eb8a42a39facdd06381c58c4 |
op_doi |
https://doi.org/10.5194/acp-16-12753-2016 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
16 |
container_issue |
19 |
container_start_page |
12753 |
op_container_end_page |
12765 |
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1766404632298389504 |