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Titel |
Particle optical backscattering along a chlorophyll gradient in the upper layer of the eastern South Pacific Ocean |
VerfasserIn |
Y. Huot, A. Morel, M. S. Twardowski, D. Stramski, R. A. Reynolds |
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 ; 5, no. 2 ; Nr. 5, no. 2 (2008-04-07), S.495-507 |
Datensatznummer |
250002381
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Publikation (Nr.) |
copernicus.org/bg-5-495-2008.pdf |
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Zusammenfassung |
The particulate scattering, bp, and backscattering, bbp,
coefficients are determined by the concentration and physical properties of
suspended particles in the ocean. They provide a simple description of the
influence of these particles on the scattering of light within the water
column. For the remote observation of ocean color, bbp along with the
total absorption coefficient govern the amount and spectral qualities of
light leaving the sea surface. However, for the construction and validation
of ocean color models measurements of bbp are still lacking, especially
at low chlorophyll a concentrations ([Chl]). Here, we examine the
relationships between spectral bbp and bp vs. [Chl] along an 8000 km
transect crossing the Case 1 waters of the eastern South Pacific Gyre. In
these waters, over the entire range of [Chl] encountered (~0.02–2 mg
m3), both bbp and bp can be related to [Chl] by power
functions (i.e. bp or bbp=α[Chl]β). Regression analyses are carried out to provide
the parameters α and β for several wavelengths throughout the
visible for both bbp and bp. When applied to the data, these
functions retrieve the same fraction of variability in bbp and bp
(coefficients of determination between 0.82 and 0.88). The bbp
coefficient fall within the bounds of previous measurements at intermediate
and high [Chl] recently published. Its dependence on [Chl] below
~0.1 mg m−3 is described for the first time with in situ data. The
backscattering ratio (i.e. bbp/bp) with values near 0.01 for all
stations appears to be spectrally neutral and not significantly dependent on
[Chl]. These results should foster the development of improved forward
models of the mean optical properties for oceanic Case 1 waters as well as
inverse models based upon them. |
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