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| Titel |
Apparent optical properties of the Canadian Beaufort Sea – Part 1: Observational overview and water column relationships |
| VerfasserIn |
D. Antoine, S. B. Hooker, S. Bélanger, A. Matsuoka, M. Babin |
| 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 ; 10, no. 7 ; Nr. 10, no. 7 (2013-07-04), S.4493-4509 |
| Datensatznummer |
250018326
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| Publikation (Nr.) |
 copernicus.org/bg-10-4493-2013.pdf |
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| Zusammenfassung |
| A data set of radiometric measurements collected in the Beaufort Sea
(Canadian Arctic) in August 2009 (Malina project) is analyzed in order to
describe apparent optical properties (AOPs) in this sea, which has been subject to
dramatic environmental changes for several decades. The two properties
derived from the measurements are the spectral diffuse attenuation
coefficient for downward irradiance, Kd, and the spectral remote
sensing reflectance, Rrs. The former controls light propagation in the
upper water column. The latter determines how light is backscattered out of
the water and becomes eventually observable from a satellite ocean color
sensor. The data set includes offshore clear waters of the Beaufort Basin as
well as highly turbid waters of the Mackenzie River plumes. In the clear
waters, we show Kd values that are much larger in the ultraviolet and
blue parts of the spectrum than what could be anticipated considering the
chlorophyll concentration. A larger contribution of absorption by colored
dissolved organic matter (CDOM) is responsible for these high Kd values,
as compared to other oligotrophic areas. In turbid waters, attenuation
reaches extremely high values, driven by high loads of particulate materials
and also by a large CDOM content. In these two extreme types of waters,
current satellite chlorophyll algorithms fail. This questions the role
of ocean color remote sensing in the Arctic when Rrs from only the
blue and green bands are used. Therefore, other parts of the spectrum (e.g.,
the red) should be explored if one aims at quantifying interannual changes
in chlorophyll in the Arctic from space. The very peculiar AOPs in the
Beaufort Sea also advocate for developing specific light propagation models
when attempting to predict light availability for photosynthesis at depth. |
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