Optimizing Models of the North Atlantic Spring Bloom Using Physical, Chemical and Bio-Optical Observations from a Lagrangian Float
The North Atlantic spring bloom is one of the main events that lead to carbon export to the deep ocean and drive oceanic uptake of CO(2) from the atmosphere. Here we use a suite of physical, bio-optical and chemical measurements made during the 2008 spring bloom to optimize and compare three differe...
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ftmaineuniv:oai:digitalcommons.library.umaine.edu:sms_facpub-1084 2024-09-15T18:14:23+00:00 Optimizing Models of the North Atlantic Spring Bloom Using Physical, Chemical and Bio-Optical Observations from a Lagrangian Float Bagniewski, W. Fennel, K. Perry, Mary Jane D'Asaro, E. A. 2011-01-01T08:00:00Z application/pdf https://digitalcommons.library.umaine.edu/sms_facpub/85 https://doi.org/10.5194/bg-8-1291-2011 https://digitalcommons.library.umaine.edu/context/sms_facpub/article/1084/viewcontent/Perry.8.5.1291.pdf unknown DigitalCommons@UMaine https://digitalcommons.library.umaine.edu/sms_facpub/85 doi:10.5194/bg-8-1291-2011 https://digitalcommons.library.umaine.edu/context/sms_facpub/article/1084/viewcontent/Perry.8.5.1291.pdf http://creativecommons.org/licenses/by/3.0/ Marine Sciences Faculty Scholarship text 2011 ftmaineuniv https://doi.org/10.5194/bg-8-1291-2011 2024-07-24T05:38:40Z The North Atlantic spring bloom is one of the main events that lead to carbon export to the deep ocean and drive oceanic uptake of CO(2) from the atmosphere. Here we use a suite of physical, bio-optical and chemical measurements made during the 2008 spring bloom to optimize and compare three different models of biological carbon export. The observations are from a Lagrangian float that operated south of Iceland from early April to late June, and were calibrated with ship-based measurements. The simplest model is representative of typical NPZD models used for the North Atlantic, while the most complex model explicitly includes diatoms and the formation of fast sinking diatom aggregates and cysts under silicate limitation. We carried out a variational optimization and error analysis for the biological parameters of all three models, and compared their ability to replicate the observations. The observations were sufficient to constrain most phytoplankton-related model parameters to accuracies of better than 15 %. However, the lack of zooplankton observations leads to large uncertainties in model parameters for grazing. The simulated vertical carbon flux at 100 m depth is similar between models and agrees well with available observations, but at 600 m the simulated flux is larger by a factor of 2.5 to 4.5 for the model with diatom aggregation. While none of the models can be formally rejected based on their misfit with the available observations, the model that includes export by diatom aggregation has a statistically significant better fit to the observations and more accurately represents the mechanisms and timing of carbon export based on observations not included in the optimization. Thus models that accurately simulate the upper 100 m do not necessarily accurately simulate export to deeper depths. Text Iceland North Atlantic The University of Maine: DigitalCommons@UMaine Biogeosciences 8 5 1291 1307 |
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The North Atlantic spring bloom is one of the main events that lead to carbon export to the deep ocean and drive oceanic uptake of CO(2) from the atmosphere. Here we use a suite of physical, bio-optical and chemical measurements made during the 2008 spring bloom to optimize and compare three different models of biological carbon export. The observations are from a Lagrangian float that operated south of Iceland from early April to late June, and were calibrated with ship-based measurements. The simplest model is representative of typical NPZD models used for the North Atlantic, while the most complex model explicitly includes diatoms and the formation of fast sinking diatom aggregates and cysts under silicate limitation. We carried out a variational optimization and error analysis for the biological parameters of all three models, and compared their ability to replicate the observations. The observations were sufficient to constrain most phytoplankton-related model parameters to accuracies of better than 15 %. However, the lack of zooplankton observations leads to large uncertainties in model parameters for grazing. The simulated vertical carbon flux at 100 m depth is similar between models and agrees well with available observations, but at 600 m the simulated flux is larger by a factor of 2.5 to 4.5 for the model with diatom aggregation. While none of the models can be formally rejected based on their misfit with the available observations, the model that includes export by diatom aggregation has a statistically significant better fit to the observations and more accurately represents the mechanisms and timing of carbon export based on observations not included in the optimization. Thus models that accurately simulate the upper 100 m do not necessarily accurately simulate export to deeper depths. |
format |
Text |
author |
Bagniewski, W. Fennel, K. Perry, Mary Jane D'Asaro, E. A. |
spellingShingle |
Bagniewski, W. Fennel, K. Perry, Mary Jane D'Asaro, E. A. Optimizing Models of the North Atlantic Spring Bloom Using Physical, Chemical and Bio-Optical Observations from a Lagrangian Float |
author_facet |
Bagniewski, W. Fennel, K. Perry, Mary Jane D'Asaro, E. A. |
author_sort |
Bagniewski, W. |
title |
Optimizing Models of the North Atlantic Spring Bloom Using Physical, Chemical and Bio-Optical Observations from a Lagrangian Float |
title_short |
Optimizing Models of the North Atlantic Spring Bloom Using Physical, Chemical and Bio-Optical Observations from a Lagrangian Float |
title_full |
Optimizing Models of the North Atlantic Spring Bloom Using Physical, Chemical and Bio-Optical Observations from a Lagrangian Float |
title_fullStr |
Optimizing Models of the North Atlantic Spring Bloom Using Physical, Chemical and Bio-Optical Observations from a Lagrangian Float |
title_full_unstemmed |
Optimizing Models of the North Atlantic Spring Bloom Using Physical, Chemical and Bio-Optical Observations from a Lagrangian Float |
title_sort |
optimizing models of the north atlantic spring bloom using physical, chemical and bio-optical observations from a lagrangian float |
publisher |
DigitalCommons@UMaine |
publishDate |
2011 |
url |
https://digitalcommons.library.umaine.edu/sms_facpub/85 https://doi.org/10.5194/bg-8-1291-2011 https://digitalcommons.library.umaine.edu/context/sms_facpub/article/1084/viewcontent/Perry.8.5.1291.pdf |
genre |
Iceland North Atlantic |
genre_facet |
Iceland North Atlantic |
op_source |
Marine Sciences Faculty Scholarship |
op_relation |
https://digitalcommons.library.umaine.edu/sms_facpub/85 doi:10.5194/bg-8-1291-2011 https://digitalcommons.library.umaine.edu/context/sms_facpub/article/1084/viewcontent/Perry.8.5.1291.pdf |
op_rights |
http://creativecommons.org/licenses/by/3.0/ |
op_doi |
https://doi.org/10.5194/bg-8-1291-2011 |
container_title |
Biogeosciences |
container_volume |
8 |
container_issue |
5 |
container_start_page |
1291 |
op_container_end_page |
1307 |
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1810452145165565952 |