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| Huang, Yin-sheng; Lee, Teh-quei; Hsu, Shu-kun. |
| We describe the orbital-scale environmental variation around Papua New Guinea (PNG) for the last 400 ka based on the environmental magnetism. Six magnetic parameters and the δ18O record of the core MD05-2928 are presented in the study. Results of magnetic analyses reveal opposite responses to different environmental conditions: Magnetic minerals were relatively fewer and finer in interglacial periods and were more and coarser in glacial periods. The reason could be suggested: In interglacial periods, sediments coming from central New Guinea were transported by the coastal currents in the northern Coral Sea and then imported to the core site location. Magnetic minerals would be relatively fewer and finer due to this longer transportation process. In glacial... |
| Tipo: Text |
Palavras-chave: Papua New Guinea; Coral Sea; Wavelet analysis; Orbital forcing; Milankovitch cycles. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00296/40694/39691.pdf |
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| Corbineau, A; Rouyer, Tristan; Cazelles, B; Fromentin, Jean-marc; Fonteneau, A; Menard, Felix. |
| We analysed the patterns of variation that characterize 33 catch time series of large pelagic fishes exploited by the Japanese and Taiwanese longline fisheries in the Indian Ocean from 1968 to 2003. We selected four species, the yellowfin (Thunnus albacares), the bigeye (T. obesus), the albacore (T. alalunga), and the swordfish (Xiphias gladius) and aggregated data into five biogeographic provinces of Longhurst (2001). We carried out wavelet analyses, an efficient method to study non-stationary time series, in order to get the time-scale patterns of each signals. We then compared and grouped the different wavelet spectra using a multivariate analysis to identify the factors (species, province or fleet) that may influence their clustering. We also... |
| Tipo: Text |
Palavras-chave: Indian Ocean; Dipole Mode Index; Longline fisheries; Wavelet analysis; Time series analysis; Pelagic fishes. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4714.pdf |
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| Ker, Stephan; Le Gonidec, Yves; Marie, Louis; Thomas, Yannick; Gibert, Dominique. |
| Seismic Oceanography is coming of age as an established technique of observation of the thermohaline structure of the ocean. The present paper deals with the seismic reflectivity of the Armorican Shelf seasonal thermocline, west of France, based on two seismic experiments performed with a sparker source. The peak frequency was 500 Hz for the ASPEX experiment, where the thermocline was located at 27 m water depth, and reduced to 400 Hz associated to a higher source level for the IFOSISMO experiment, where the thermocline was 12 m deeper. Despite this settings, only the first experiment could clearly highlight the thermocline reflector, providing the first seismic observation of a shallow oceanic structure. To better understand the limitation of... |
| Tipo: Text |
Palavras-chave: Thermocline; Seismic method; Wavelet analysis; Acoustic. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00254/36535/35066.pdf |
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| Navarro, Gabriel; Almaraz, Pablo; Caballero, Isabel; Vazquez, Agueda; Huertas, Isabel E.. |
| During the last two decades, several satellite algorithms have been proposed to retrieve information about phytoplankton groups using ocean color data. One of these algorithms, the so-called PHYSAT-Med, was developed specifically for the Mediterranean Sea due to the optical peculiarities of this basin. The method allows the detection from ocean color images of the dominant Mediterranean phytoplankton groups, namely nanoeukaryotes, Prochlorococcus. Synechococcus, diatoms, coccolithophorids, and Phaeocystis-like phytoplankton. Here, we present a new version of PHYSAT-Med applied to the Ocean Colour Climate Change Initiative (OC-CCI) database. The OC-CCI database consists of a multi-sensor, global ocean-color product that merges observations from four... |
| Tipo: Text |
Palavras-chave: PHYSAT-Med algorithm; OC-CCI database; Phytoplankton functional types; Mediterranean Sea; Wavelet analysis. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00589/70148/68133.pdf |
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| Horng, Cs; Roberts, Ap; Liang, Wt. |
| We present a 2.14-Myr astronomically tuned relative geomagnetic paleointensity record from the western Philippine Sea. Pseudosingle-domain titanomagnetite is the only magnetic mineral identified and variations in titanomagnetite concentration fall well within the accepted limits for relative paleointensity variations. No significant temporally persistent periodicities are observed in wavelet analyses of the paleointensity time series or in the rock magnetic parameters used for relative paleointensity normalization. This suggests that our paleointensity record is largely free of rock magnetic or lithological artefacts and that it represents a reliable record of geomagnetic behavior with no evidence for modulation of the field at Earth orbital periods. The... |
| Tipo: Text |
Palavras-chave: Geomagnetic paleointensity; Magnetostratigraphy; Spectral analysis; Wavelet analysis; Philippine Sea. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00224/33554/31978.pdf |
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