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| Titel |
Using satellite-derived backscattering coefficients in addition to chlorophyll data to constrain a simple marine biogeochemical model |
| VerfasserIn |
H. Kettle |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 6, no. 8 ; Nr. 6, no. 8 (2009-08-10), S.1591-1601 |
| Datensatznummer |
250003949
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| Publikation (Nr.) |
 copernicus.org/bg-6-1591-2009.pdf |
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| Zusammenfassung |
| Biogeochemical models of the ocean carbon cycle are frequently validated by,
or tuned to, satellite chlorophyll data. However, ocean carbon cycle models
are required to accurately model the movement of carbon, not chlorophyll, and
due to the high variability of the carbon to chlorophyll ratio in
phytoplankton, chlorophyll is not a robust proxy for carbon. Using inherent
optical property (IOP) inversion algorithms it is now possible to also derive
the amount of light backscattered by the upper ocean (bb) which is related
to the amount of particulate organic carbon (POC) present. Using empirical
relationships between POC and bb, a 1-D marine biogeochemical model is
used to simulate bb at 490 nm thereby allowing the model to be compared
with both remotely-sensed chlorophyll or bb data. Here I investigate the
possibility of using bb in conjunction with chlorophyll data to help
constrain the parameters in a simple 1-D NPZD model. The parameters of the
biogeochemical model are tuned with a genetic algorithm, so that the model is
fitted to either chlorophyll data or to both chlorophyll and bb data at
three sites in the Atlantic with very different characteristics. Several
inherent optical property (IOP) algorithms are available for estimating
bb, three of which are used here. The effect of the different bb
datasets on the behaviour of the tuned model is examined to ascertain whether
the uncertainty in bb is significant. The results show that the addition
of bb data does not consistently alter the same model parameters at each
site and in fact can lead to some parameters becoming less well constrained,
implying there is still much work to be done on the mechanisms relating
chlorophyll to POC and bb within the model. However, this study does
indicate that including bb data has the potential to significantly effect
the modelled mixed layer detritus and that uncertainties in bb due to the
different IOP algorithms are not particularly significant. |
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