Relationship between the sub-micron fraction (SMF) and fine-mode fraction (FMF) in the context of AERONET retrievals
The sub-micron (SM) aerosol optical depth (AOD) is an optical separation based on the fraction of particles below a specified cutoff radius of the particle size distribution (PSD) at a given particle radius. It is fundamentally different from spectrally separated FM (fine-mode) AOD. We present a sim...
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ftdoajarticles:oai:doaj.org/article:60f65ad75a144662b6feff39fc0646a8 2023-05-15T15:14:40+02:00 Relationship between the sub-micron fraction (SMF) and fine-mode fraction (FMF) in the context of AERONET retrievals N. T. O'Neill K. Ranjbar L. Ivănescu T. F. Eck J. S. Reid D. M. Giles D. Pérez-Ramírez J. P. Chaubey 2023-03-01T00:00:00Z https://doi.org/10.5194/amt-16-1103-2023 https://doaj.org/article/60f65ad75a144662b6feff39fc0646a8 EN eng Copernicus Publications https://amt.copernicus.org/articles/16/1103/2023/amt-16-1103-2023.pdf https://doaj.org/toc/1867-1381 https://doaj.org/toc/1867-8548 doi:10.5194/amt-16-1103-2023 1867-1381 1867-8548 https://doaj.org/article/60f65ad75a144662b6feff39fc0646a8 Atmospheric Measurement Techniques, Vol 16, Pp 1103-1120 (2023) Environmental engineering TA170-171 Earthwork. Foundations TA715-787 article 2023 ftdoajarticles https://doi.org/10.5194/amt-16-1103-2023 2023-03-05T01:30:39Z The sub-micron (SM) aerosol optical depth (AOD) is an optical separation based on the fraction of particles below a specified cutoff radius of the particle size distribution (PSD) at a given particle radius. It is fundamentally different from spectrally separated FM (fine-mode) AOD. We present a simple (AOD-normalized) SM fraction versus FM fraction (SMF vs. FMF) linear equation that explains the well-recognized empirical result of SMF generally being greater than the FMF. The AERONET inversion (AERinv) products (combined inputs of spectral AOD and sky radiance) and the spectral deconvolution algorithm (SDA) products (input of AOD spectra) enable, respectively, an empirical SMF vs. FMF comparison at similar (columnar) remote sensing scales across a variety of aerosol types. SMF (AERinv-derived) vs. FMF (SDA-derived) behavior is primarily dependent on the relative truncated portion ( ε c ) of the coarse-mode (CM) AOD associated with the cutoff portion of the CM PSD and, to a second order, the cutoff FM PSD and FM AOD ( ε f ). The SMF vs. FMF equation largely explains the SMF vs. FMF behavior of the AERinv vs. SDA products as a function of PSD cutoff radius (“inflection point”) across an ensemble of AERONET sites and aerosol types (urban-industrial, biomass burning, dust, maritime and a mixed class of Arctic aerosols). The overarching dynamic was that the linear SMF vs. FMF relation pivots clockwise about the approximate (SMF, FMF) singularity of (1, 1) in a “linearly inverse” fashion (slope and intercept of approximately 1− ε c and ε c ) with increasing cutoff radius. SMF vs. FMF slopes and intercepts derived from AERinv and SDA retrievals confirmed the general domination of ε c over ε f in controlling that dynamic. A more general conclusion is the apparent confirmation that the optical impact of truncating modal (whole) PSD features can be detected by an SMF vs. FMF analysis. Article in Journal/Newspaper Arctic Directory of Open Access Journals: DOAJ Articles Arctic Atmospheric Measurement Techniques 16 4 1103 1120 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental engineering TA170-171 Earthwork. Foundations TA715-787 |
spellingShingle |
Environmental engineering TA170-171 Earthwork. Foundations TA715-787 N. T. O'Neill K. Ranjbar L. Ivănescu T. F. Eck J. S. Reid D. M. Giles D. Pérez-Ramírez J. P. Chaubey Relationship between the sub-micron fraction (SMF) and fine-mode fraction (FMF) in the context of AERONET retrievals |
topic_facet |
Environmental engineering TA170-171 Earthwork. Foundations TA715-787 |
description |
The sub-micron (SM) aerosol optical depth (AOD) is an optical separation based on the fraction of particles below a specified cutoff radius of the particle size distribution (PSD) at a given particle radius. It is fundamentally different from spectrally separated FM (fine-mode) AOD. We present a simple (AOD-normalized) SM fraction versus FM fraction (SMF vs. FMF) linear equation that explains the well-recognized empirical result of SMF generally being greater than the FMF. The AERONET inversion (AERinv) products (combined inputs of spectral AOD and sky radiance) and the spectral deconvolution algorithm (SDA) products (input of AOD spectra) enable, respectively, an empirical SMF vs. FMF comparison at similar (columnar) remote sensing scales across a variety of aerosol types. SMF (AERinv-derived) vs. FMF (SDA-derived) behavior is primarily dependent on the relative truncated portion ( ε c ) of the coarse-mode (CM) AOD associated with the cutoff portion of the CM PSD and, to a second order, the cutoff FM PSD and FM AOD ( ε f ). The SMF vs. FMF equation largely explains the SMF vs. FMF behavior of the AERinv vs. SDA products as a function of PSD cutoff radius (“inflection point”) across an ensemble of AERONET sites and aerosol types (urban-industrial, biomass burning, dust, maritime and a mixed class of Arctic aerosols). The overarching dynamic was that the linear SMF vs. FMF relation pivots clockwise about the approximate (SMF, FMF) singularity of (1, 1) in a “linearly inverse” fashion (slope and intercept of approximately 1− ε c and ε c ) with increasing cutoff radius. SMF vs. FMF slopes and intercepts derived from AERinv and SDA retrievals confirmed the general domination of ε c over ε f in controlling that dynamic. A more general conclusion is the apparent confirmation that the optical impact of truncating modal (whole) PSD features can be detected by an SMF vs. FMF analysis. |
format |
Article in Journal/Newspaper |
author |
N. T. O'Neill K. Ranjbar L. Ivănescu T. F. Eck J. S. Reid D. M. Giles D. Pérez-Ramírez J. P. Chaubey |
author_facet |
N. T. O'Neill K. Ranjbar L. Ivănescu T. F. Eck J. S. Reid D. M. Giles D. Pérez-Ramírez J. P. Chaubey |
author_sort |
N. T. O'Neill |
title |
Relationship between the sub-micron fraction (SMF) and fine-mode fraction (FMF) in the context of AERONET retrievals |
title_short |
Relationship between the sub-micron fraction (SMF) and fine-mode fraction (FMF) in the context of AERONET retrievals |
title_full |
Relationship between the sub-micron fraction (SMF) and fine-mode fraction (FMF) in the context of AERONET retrievals |
title_fullStr |
Relationship between the sub-micron fraction (SMF) and fine-mode fraction (FMF) in the context of AERONET retrievals |
title_full_unstemmed |
Relationship between the sub-micron fraction (SMF) and fine-mode fraction (FMF) in the context of AERONET retrievals |
title_sort |
relationship between the sub-micron fraction (smf) and fine-mode fraction (fmf) in the context of aeronet retrievals |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/amt-16-1103-2023 https://doaj.org/article/60f65ad75a144662b6feff39fc0646a8 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
Atmospheric Measurement Techniques, Vol 16, Pp 1103-1120 (2023) |
op_relation |
https://amt.copernicus.org/articles/16/1103/2023/amt-16-1103-2023.pdf https://doaj.org/toc/1867-1381 https://doaj.org/toc/1867-8548 doi:10.5194/amt-16-1103-2023 1867-1381 1867-8548 https://doaj.org/article/60f65ad75a144662b6feff39fc0646a8 |
op_doi |
https://doi.org/10.5194/amt-16-1103-2023 |
container_title |
Atmospheric Measurement Techniques |
container_volume |
16 |
container_issue |
4 |
container_start_page |
1103 |
op_container_end_page |
1120 |
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