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Titel |
Natural variability of bio-optical properties in Case 1 waters: attenuation and reflectance within the visible and near-UV spectral domains, as observed in South Pacific and Mediterranean waters |
VerfasserIn |
A. Morel, H. Claustre, D. Antoine, B. Gentili |
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 ; 4, no. 5 ; Nr. 4, no. 5 (2007-10-26), S.913-925 |
Datensatznummer |
250001970
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Publikation (Nr.) |
copernicus.org/bg-4-913-2007.pdf |
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Zusammenfassung |
The optical properties of Case 1 waters have been empirically related to the
chlorophyll concentration, [Chl], historically used as an index of the
trophic state and of the abundance of the biological materials. The
well-known natural variability around the mean statistical relationships is
here examined by comparing the apparent optical properties (spectral
downward irradiance attenuation and reflectance) as a function of [Chl] in
two Case 1 environments, the Pacific and Mediterranean waters. These oceanic
zones apparently represent two extremes of the possible bio-optical
variability range around the mean. The systematic deviations, in both
directions with respect to the average laws, mainly result from the
differing contents in non-algal detrital materials and dissolved colored
substance for a given [Chl] level. These contents are higher than the
average in the Mediterranean Sea, and lower in the Pacific Ocean,
respectively. These divergences between the two water bodies, detectable in
the visible spectral domain, are considerably accentuated in the UV domain.
The bio-optical properties in this spectral domain (310–400 nm) are
systematically explored. They are more varying for a given [Chl] than those
in the visible domain. Their prediction based on the sole [Chl] index is
thus problematic, although it is probably possible on a regional scale if
reliable field data are available. It does not seem, however, that
ubiquitous relationships exist for this spectral domain for all Case 1
waters at global scale. |
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