A global end-member approach to derive a CDOM (440) from near-surface optical measurements
This study establishes an optical inversion scheme for deriving the absorption coefficient of colored (or chromophoric, depending on the literature) dissolved organic material (CDOM) at the 440 nm wavelength, which can be applied to global water masses with near-equal efficacy. The approach uses a r...
Published in: | Biogeosciences |
---|---|
Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2020
|
Subjects: | |
Online Access: | https://doi.org/10.5194/bg-17-475-2020 https://doaj.org/article/8a64830d73634ce9bfe3bed1faba9b14 |
id |
ftdoajarticles:oai:doaj.org/article:8a64830d73634ce9bfe3bed1faba9b14 |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:8a64830d73634ce9bfe3bed1faba9b14 2023-05-15T15:14:49+02:00 A global end-member approach to derive a CDOM (440) from near-surface optical measurements S. B. Hooker A. Matsuoka R. M. Kudela Y. Yamashita K. Suzuki H. F. Houskeeper 2020-01-01T00:00:00Z https://doi.org/10.5194/bg-17-475-2020 https://doaj.org/article/8a64830d73634ce9bfe3bed1faba9b14 EN eng Copernicus Publications https://www.biogeosciences.net/17/475/2020/bg-17-475-2020.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-17-475-2020 1726-4170 1726-4189 https://doaj.org/article/8a64830d73634ce9bfe3bed1faba9b14 Biogeosciences, Vol 17, Pp 475-497 (2020) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2020 ftdoajarticles https://doi.org/10.5194/bg-17-475-2020 2022-12-31T03:37:12Z This study establishes an optical inversion scheme for deriving the absorption coefficient of colored (or chromophoric, depending on the literature) dissolved organic material (CDOM) at the 440 nm wavelength, which can be applied to global water masses with near-equal efficacy. The approach uses a ratio of diffuse attenuation coefficient spectral end-members, i.e., a short- and long-wavelength pair. The global perspective is established by sampling “extremely” clear water plus a generalized extent in turbidity and optical properties that each span 3 decades of dynamic range. A unique data set was collected in oceanic, coastal, and inland waters (as shallow as 0.6 m) from the North Pacific Ocean, the Arctic Ocean, Hawaii, Japan, Puerto Rico, and the western coast of the United States. The data were partitioned using subjective categorizations to define a validation quality subset of conservative water masses (i.e., the inflow and outflow of properties constrain the range in the gradient of a constituent) plus 15 subcategories of more complex water masses that were not necessarily evolving conservatively. The dependence on optical complexity was confirmed with an objective methodology based on a cluster analysis technique. The latter defined five distinct classes with validation quality data present in all classes, but which also decreased in percent composition as a function of increasing class number and optical complexity. Four algorithms based on different validation quality end-members were validated with accuracies of 1.2 %–6.2 %, wherein pairs with the largest spectral span were most accurate. Although algorithm accuracy decreased with the inclusion of more subcategories containing nonconservative water masses, changes to the algorithm fit were small when a preponderance of subcategories were included. The high accuracy for all end-member algorithms was the result of data acquisition and data processing improvements, e.g., increased vertical sampling resolution to less than 1 mm (with pressure transducer ... Article in Journal/Newspaper Arctic Arctic Ocean Directory of Open Access Journals: DOAJ Articles Arctic Arctic Ocean Pacific Biogeosciences 17 2 475 497 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 S. B. Hooker A. Matsuoka R. M. Kudela Y. Yamashita K. Suzuki H. F. Houskeeper A global end-member approach to derive a CDOM (440) from near-surface optical measurements |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
This study establishes an optical inversion scheme for deriving the absorption coefficient of colored (or chromophoric, depending on the literature) dissolved organic material (CDOM) at the 440 nm wavelength, which can be applied to global water masses with near-equal efficacy. The approach uses a ratio of diffuse attenuation coefficient spectral end-members, i.e., a short- and long-wavelength pair. The global perspective is established by sampling “extremely” clear water plus a generalized extent in turbidity and optical properties that each span 3 decades of dynamic range. A unique data set was collected in oceanic, coastal, and inland waters (as shallow as 0.6 m) from the North Pacific Ocean, the Arctic Ocean, Hawaii, Japan, Puerto Rico, and the western coast of the United States. The data were partitioned using subjective categorizations to define a validation quality subset of conservative water masses (i.e., the inflow and outflow of properties constrain the range in the gradient of a constituent) plus 15 subcategories of more complex water masses that were not necessarily evolving conservatively. The dependence on optical complexity was confirmed with an objective methodology based on a cluster analysis technique. The latter defined five distinct classes with validation quality data present in all classes, but which also decreased in percent composition as a function of increasing class number and optical complexity. Four algorithms based on different validation quality end-members were validated with accuracies of 1.2 %–6.2 %, wherein pairs with the largest spectral span were most accurate. Although algorithm accuracy decreased with the inclusion of more subcategories containing nonconservative water masses, changes to the algorithm fit were small when a preponderance of subcategories were included. The high accuracy for all end-member algorithms was the result of data acquisition and data processing improvements, e.g., increased vertical sampling resolution to less than 1 mm (with pressure transducer ... |
format |
Article in Journal/Newspaper |
author |
S. B. Hooker A. Matsuoka R. M. Kudela Y. Yamashita K. Suzuki H. F. Houskeeper |
author_facet |
S. B. Hooker A. Matsuoka R. M. Kudela Y. Yamashita K. Suzuki H. F. Houskeeper |
author_sort |
S. B. Hooker |
title |
A global end-member approach to derive a CDOM (440) from near-surface optical measurements |
title_short |
A global end-member approach to derive a CDOM (440) from near-surface optical measurements |
title_full |
A global end-member approach to derive a CDOM (440) from near-surface optical measurements |
title_fullStr |
A global end-member approach to derive a CDOM (440) from near-surface optical measurements |
title_full_unstemmed |
A global end-member approach to derive a CDOM (440) from near-surface optical measurements |
title_sort |
global end-member approach to derive a cdom (440) from near-surface optical measurements |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/bg-17-475-2020 https://doaj.org/article/8a64830d73634ce9bfe3bed1faba9b14 |
geographic |
Arctic Arctic Ocean Pacific |
geographic_facet |
Arctic Arctic Ocean Pacific |
genre |
Arctic Arctic Ocean |
genre_facet |
Arctic Arctic Ocean |
op_source |
Biogeosciences, Vol 17, Pp 475-497 (2020) |
op_relation |
https://www.biogeosciences.net/17/475/2020/bg-17-475-2020.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-17-475-2020 1726-4170 1726-4189 https://doaj.org/article/8a64830d73634ce9bfe3bed1faba9b14 |
op_doi |
https://doi.org/10.5194/bg-17-475-2020 |
container_title |
Biogeosciences |
container_volume |
17 |
container_issue |
2 |
container_start_page |
475 |
op_container_end_page |
497 |
_version_ |
1766345220601937920 |