Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model
We present a numerical model of the ocean that couples a three-stream radiative transfer component with a marine biogeochemical–ecosystem component in a dynamic three-dimensional physical framework. The radiative transfer component resolves the penetration of spectral irradiance as it is absorbed an...
| Main Authors: | , , , , , |
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| Format: | Article |
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Copernicus GmbH
2018
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| Online Access: | http://hdl.handle.net/1721.1/118365 https://orcid.org/0000-0002-3102-0341 |
| _version_ | 1811068467309182976 |
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| author | Dutkiewicz, S. Hickman, A. E. Gregg, W. W. Mouw, C. B. Jahn, Oliver Follows, Michael J |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Dutkiewicz, S. Hickman, A. E. Gregg, W. W. Mouw, C. B. Jahn, Oliver Follows, Michael J |
| author_sort | Dutkiewicz, S. |
| collection | MIT |
| description | We present a numerical model of the ocean that couples a three-stream radiative transfer component with a marine biogeochemical–ecosystem component in a dynamic three-dimensional physical framework. The radiative transfer component resolves the penetration of spectral irradiance as it is absorbed and scattered within the water column. We explicitly include the effect of several optically important water constituents (different phytoplankton functional types; detrital particles; and coloured dissolved organic matter, CDOM). The model is evaluated against in situ-observed and satellite-derived products. In particular we compare to concurrently measured biogeochemical, ecosystem, and optical data along a meridional transect of the Atlantic Ocean. The simulation captures the patterns and magnitudes of these data, and estimates surface upwelling irradiance analogous to that observed by ocean colour satellite instruments. We find that incorporating the different optically important constituents explicitly and including spectral irradiance was crucial
to capture the variability in the depth of the subsurface chlorophyll a (Chl a) maximum. We conduct a series of sensitivity experiments to demonstrate, globally, the relative
importance of each of the water constituents, as well as the crucial feedbacks between the light field, the relative fitness of phytoplankton types, and the biogeochemistry of
the ocean. CDOM has proportionally more importance at attenuating light at short wavelengths and in more productive waters, phytoplankton absorption is relatively more important at the subsurface Chl a maximum, and water molecules have the greatest contribution when concentrations of other constituents are low, such as in the oligotrophic gyres. Scattering had less effect on attenuation, but since it is important for the amount and type of upwelling irradiance, it is crucial for setting sea surface reflectance. Strikingly, sensitivity experiments in which absorption by any of the optical constituents was increased led to a decrease in the size of the oligotrophic regions of the subtropical gyres: lateral
nutrient supplies were enhanced as a result of decreasing high-latitude productivity. This new model that captures biooptical feedbacks will be important for improving our understanding of the role of light and optical constituents on ocean biogeochemistry, especially in a changing environment. Further, resolving surface upwelling irradiance will make it easier to connect to satellite-derived products in the future. |
| first_indexed | 2024-09-23T07:56:27Z |
| format | Article |
| id | mit-1721.1/118365 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T07:56:27Z |
| publishDate | 2018 |
| publisher | Copernicus GmbH |
| record_format | dspace |
| spelling | mit-1721.1/1183652022-09-23T09:47:55Z Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model Dutkiewicz, S. Hickman, A. E. Gregg, W. W. Mouw, C. B. Jahn, Oliver Follows, Michael J Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Jahn, Oliver Follows, Michael J We present a numerical model of the ocean that couples a three-stream radiative transfer component with a marine biogeochemical–ecosystem component in a dynamic three-dimensional physical framework. The radiative transfer component resolves the penetration of spectral irradiance as it is absorbed and scattered within the water column. We explicitly include the effect of several optically important water constituents (different phytoplankton functional types; detrital particles; and coloured dissolved organic matter, CDOM). The model is evaluated against in situ-observed and satellite-derived products. In particular we compare to concurrently measured biogeochemical, ecosystem, and optical data along a meridional transect of the Atlantic Ocean. The simulation captures the patterns and magnitudes of these data, and estimates surface upwelling irradiance analogous to that observed by ocean colour satellite instruments. We find that incorporating the different optically important constituents explicitly and including spectral irradiance was crucial to capture the variability in the depth of the subsurface chlorophyll a (Chl a) maximum. We conduct a series of sensitivity experiments to demonstrate, globally, the relative importance of each of the water constituents, as well as the crucial feedbacks between the light field, the relative fitness of phytoplankton types, and the biogeochemistry of the ocean. CDOM has proportionally more importance at attenuating light at short wavelengths and in more productive waters, phytoplankton absorption is relatively more important at the subsurface Chl a maximum, and water molecules have the greatest contribution when concentrations of other constituents are low, such as in the oligotrophic gyres. Scattering had less effect on attenuation, but since it is important for the amount and type of upwelling irradiance, it is crucial for setting sea surface reflectance. Strikingly, sensitivity experiments in which absorption by any of the optical constituents was increased led to a decrease in the size of the oligotrophic regions of the subtropical gyres: lateral nutrient supplies were enhanced as a result of decreasing high-latitude productivity. This new model that captures biooptical feedbacks will be important for improving our understanding of the role of light and optical constituents on ocean biogeochemistry, especially in a changing environment. Further, resolving surface upwelling irradiance will make it easier to connect to satellite-derived products in the future. United States. National Aeronautics and Space Administration (Grant NNX13AC34G) National Science Foundation (U.S.) (Grant OCE1434007) National Science Foundation (U.S.) (Grant OCE1155295) 2018-10-04T19:43:51Z 2018-10-04T19:43:51Z 2015-07 2015-06 2018-09-24T18:59:44Z Article http://purl.org/eprint/type/JournalArticle 1810-6285 http://hdl.handle.net/1721.1/118365 Dutkiewicz, S. et al “Capturing Optically Important Constituents and Properties in a Marine Biogeochemical and Ecosystem Model.” Biogeosciences Discussions 12, 3 (February 2015): 2607–2695 © 2015 Author(s) https://orcid.org/0000-0002-3102-0341 http://dx.doi.org/10.5194/BGD-12-2607-2015 Biogeosciences Discussions Creative Commons Attribution 3.0 Unported license http://creativecommons.org/licenses/by/3.0/ application/pdf Copernicus GmbH Copernicus Publications |
| spellingShingle | Dutkiewicz, S. Hickman, A. E. Gregg, W. W. Mouw, C. B. Jahn, Oliver Follows, Michael J Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model |
| title | Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model |
| title_full | Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model |
| title_fullStr | Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model |
| title_full_unstemmed | Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model |
| title_short | Capturing optically important constituents and properties in a marine biogeochemical and ecosystem model |
| title_sort | capturing optically important constituents and properties in a marine biogeochemical and ecosystem model |
| url | http://hdl.handle.net/1721.1/118365 https://orcid.org/0000-0002-3102-0341 |
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