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| Titel |
Contribution to a bio-optical model for remote sensing of Lena River water |
| VerfasserIn |
H. Örek, R. Doerffer, R. Röttgers, M. Boersma, K. H. Wiltshire |
| 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. 11 ; Nr. 10, no. 11 (2013-11-08), S.7081-7094 |
| Datensatznummer |
250085401
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| Publikation (Nr.) |
 copernicus.org/bg-10-7081-2013.pdf |
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| Zusammenfassung |
| Bio-optical measurements and sampling were carried out in the delta of the
Lena River (northern Siberia, Russia) between 26 June and 4 July 2011. The
aim of this study was to determine the inherent optical properties of the
Lena water, i.e., absorption, attenuation, and scattering coefficients, during
the period of maximum runoff. This aimed to contribute to the development
of a bio-optical model for use as the basis for optical remote sensing of
coastal water of the Arctic. In this context the absorption by CDOM (colored
dissolved organic matter) and particles, and the concentrations of total suspended matter, phytoplankton-pigments, and carbon were measured. CDOM
was found to be the most dominant parameter affecting the optical properties
of the river, with an absorption coefficient of 4.5–5 m−1 at 442 nm,
which was almost four times higher than total particle absorption values at
visible wavelength range. The wavelenght-dependence of absorption of the different water constituents was chracterized by determining the semi logarithmic
spectral slope. Mean CDOM, and detritus slopes were 0.0149
nm−1(standard deviation (stdev) = 0.0003, n = 18), and 0.0057
nm−1 (stdev = 0.0017, n = 19), respectively, values which are
typical for water bodies with high concentrations of dissolved and
particulate carbon. Mean chlorophyll a and total suspended matter were 1.8 mg m−3 (stdev = 0.734 n = 18) and 31.9 g m−3
(stdev = 19.94, n = 27), respectively. DOC (dissolved organic carbon) was in the range 8–10 g m−3 and the
total particulate carbon (PC) in the range 0.25–1.5 g m−3. The light
penetration depth (Secchi disc depth) was in the range 30–90 cm and was
highly correlated with the suspended matter concentration. The period of
maximum river runoff in June was chosen to obtain bio-optical data when
maximum water constituents are transported into the Laptev Sea. However, we
are aware that more data from other seasons and other years need to be
collected to establish a general bio-optical model of the Lena water and
conclusively characterize the light climate with respect to primary
production. |
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