995 resultados para 725


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In this paper, modernized shipborne procedures are presented to collect and process above-water radiometry for remote sensing applications. A setup of five radiometers and a bidirectional camera system, which provides panoramic sea surface and sky images, is proposed for the collection of high-resolution radiometric quantities. Images from the camera system can be used to determine sky state and potential glint, whitecaps, or foam contamination. A peak in the observed remote sensing reflectance RRS spectra between 750-780 nm was typically found in spectra with relatively high surface reflected glint (SRG), which suggests this waveband could be a useful SRG indicator. Simplified steps for computing uncertainties in SRG corrected RRS are proposed and discussed. The potential of utilizing "unweighted multimodel averaging," which is the average of four or more common SRG correction models, is examined to determine the best approximation RRS. This best approximation RRS provides an estimate of RRS based on various SRG correction models established using radiative transfer simulations and field investigations. Applying the average RRS provides a measure of the inherent uncertainties or biases that result from a user subjectively choosing any one SRG correction model. Comparisons between inherent and apparent optical property derived observations were used to assess the robustness of the SRG multimodel averaging ap- proach. Correlations among the standard SRG models were completed to determine the degree of association or similarities between the SRG models. Results suggest that the choice of glint models strongly affects derived RRS values and can also influence the blue to green band ratios used for modeling biogeochemical parameters such as for chlorophyll a. The objective here is to present a uniform and traceable methodology for determining ship- borne RRS measurements and its associated errors due to glint correction and to ensure the direct comparability of these measurements in future investigations. We encourage the ocean color community to publish radiometric field measurements with matching and complete metadata in open access repositories.

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Vertical distribution of common zooplankton species is examined on the base of two series of layer-by-layer net catches down to depth of 3400 m. Differences between the series are significant for most species only near the surface, whereas in deeper layers character of distribution remains the same. Great depths in the Sea of Japan are populated most actively by species performing intensive daily migrations, and less actively by species continuously confined to a definite depth range. Different character of nutrition of the animals apparently determines extent of utilization of deep layers, which are usual for the species.

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The solvent-extractable organic fractions of sediment samples from six Ocean Drilling Program Leg 117 sites were investigated by gas chromatography and gas chromatography-mass spectrometry. Sediments deposited in the Indus Fan (Site 720) as well as Miocene sediments from the Owen Ridge (Sites 722 and 731) contain almost exclusively organic matter of terrigenous origin. The organic matter in sediments from the Oman Margin (Sites 723, 725, and 728) and in the Pliocene/Pleistocene sections from the Owen Ridge is mainly of a marine origin with variable admixtures of terrigenous material. In these latter samples strong variations of the lipid composition and distribution are noted. However, the interpretation of the relation to potential biological sources is hampered by a lack of information on the possible lipid composition of appropriate organisms.