Remote sensing the sea surface CO<sub>2</sub> of the Baltic Sea using the SOMLO methodology

Studies of coastal seas in Europe have noted the high variability of the CO<sub>2</sub> system. This high variability, generated by the complex mechanisms driving the CO<sub>2</sub> fluxes, complicates the accurate estimation of these mechanisms. This is particularly prono...

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Main Authors: G. Parard, A. A. Charantonis, A. Rutgerson
Format: Article
Language:English
Published: Copernicus Publications 2015-06-01
Series:Biogeosciences
Online Access:https://www.biogeosciences.net/12/3369/2015/bg-12-3369-2015.pdf
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author G. Parard
A. A. Charantonis
A. A. Charantonis
A. Rutgerson
author_facet G. Parard
A. A. Charantonis
A. A. Charantonis
A. Rutgerson
author_sort G. Parard
collection DOAJ
description Studies of coastal seas in Europe have noted the high variability of the CO<sub>2</sub> system. This high variability, generated by the complex mechanisms driving the CO<sub>2</sub> fluxes, complicates the accurate estimation of these mechanisms. This is particularly pronounced in the Baltic Sea, where the mechanisms driving the fluxes have not been characterized in as much detail as in the open oceans. In addition, the joint availability of in situ measurements of CO<sub>2</sub> and of sea-surface satellite data is limited in the area. In this paper, we used the SOMLO (self-organizing multiple linear output; Sasse et al., 2013) methodology, which combines two existing methods (i.e. self-organizing maps and multiple linear regression) to estimate the ocean surface partial pressure of CO<sub>2</sub> (<i>p</i>CO<sub>2</sub>) in the Baltic Sea from the remotely sensed sea surface temperature, chlorophyll, coloured dissolved organic matter, net primary production, and mixed-layer depth. The outputs of this research have a horizontal resolution of 4 km and cover the 1998–2011 period. These outputs give a monthly map of the Baltic Sea at a very fine spatial resolution. The reconstructed <i>p</i>CO<sub>2</sub> values over the validation data set have a correlation of 0.93 with the in situ measurements and a root mean square error of 36 μatm. Removing any of the satellite parameters degraded this reconstructed CO<sub>2</sub> flux, so we chose to supply any missing data using statistical imputation. The <i>p</i>CO<sub>2</sub> maps produced using this method also provide a confidence level of the reconstruction at each grid point. The results obtained are encouraging given the sparsity of available data, and we expect to be able to produce even more accurate reconstructions in coming years, given the predicted acquisition of new data.
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spelling doaj.art-f7a797abced24218a36fc2276bf8974a2022-12-21T18:57:54ZengCopernicus PublicationsBiogeosciences1726-41701726-41892015-06-01123369338410.5194/bg-12-3369-2015Remote sensing the sea surface CO<sub>2</sub> of the Baltic Sea using the SOMLO methodologyG. Parard0A. A. Charantonis1A. A. Charantonis2A. Rutgerson3Department of Earth Sciences, Uppsala University, Uppsala, SwedenCentre d'études et de recherche en informatique, Conservatoire des Arts et Métiers, Paris, FranceLaboratoire d'océanographie et du climat: expérimentations et approches numériques, Université Pierre et Marie Curie, Paris, FranceDepartment of Earth Sciences, Uppsala University, Uppsala, SwedenStudies of coastal seas in Europe have noted the high variability of the CO<sub>2</sub> system. This high variability, generated by the complex mechanisms driving the CO<sub>2</sub> fluxes, complicates the accurate estimation of these mechanisms. This is particularly pronounced in the Baltic Sea, where the mechanisms driving the fluxes have not been characterized in as much detail as in the open oceans. In addition, the joint availability of in situ measurements of CO<sub>2</sub> and of sea-surface satellite data is limited in the area. In this paper, we used the SOMLO (self-organizing multiple linear output; Sasse et al., 2013) methodology, which combines two existing methods (i.e. self-organizing maps and multiple linear regression) to estimate the ocean surface partial pressure of CO<sub>2</sub> (<i>p</i>CO<sub>2</sub>) in the Baltic Sea from the remotely sensed sea surface temperature, chlorophyll, coloured dissolved organic matter, net primary production, and mixed-layer depth. The outputs of this research have a horizontal resolution of 4 km and cover the 1998–2011 period. These outputs give a monthly map of the Baltic Sea at a very fine spatial resolution. The reconstructed <i>p</i>CO<sub>2</sub> values over the validation data set have a correlation of 0.93 with the in situ measurements and a root mean square error of 36 μatm. Removing any of the satellite parameters degraded this reconstructed CO<sub>2</sub> flux, so we chose to supply any missing data using statistical imputation. The <i>p</i>CO<sub>2</sub> maps produced using this method also provide a confidence level of the reconstruction at each grid point. The results obtained are encouraging given the sparsity of available data, and we expect to be able to produce even more accurate reconstructions in coming years, given the predicted acquisition of new data.https://www.biogeosciences.net/12/3369/2015/bg-12-3369-2015.pdf
spellingShingle G. Parard
A. A. Charantonis
A. A. Charantonis
A. Rutgerson
Remote sensing the sea surface CO<sub>2</sub> of the Baltic Sea using the SOMLO methodology
Biogeosciences
title Remote sensing the sea surface CO<sub>2</sub> of the Baltic Sea using the SOMLO methodology
title_full Remote sensing the sea surface CO<sub>2</sub> of the Baltic Sea using the SOMLO methodology
title_fullStr Remote sensing the sea surface CO<sub>2</sub> of the Baltic Sea using the SOMLO methodology
title_full_unstemmed Remote sensing the sea surface CO<sub>2</sub> of the Baltic Sea using the SOMLO methodology
title_short Remote sensing the sea surface CO<sub>2</sub> of the Baltic Sea using the SOMLO methodology
title_sort remote sensing the sea surface co sub 2 sub of the baltic sea using the somlo methodology
url https://www.biogeosciences.net/12/3369/2015/bg-12-3369-2015.pdf
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