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351.
An unrealistically high-salinity maximum is found to develop in a high-resolution model of the north and equatorial Atlantic below the shallow halocline in the Gulf of Guinea. The spurious water mass with salinities too high by as much as 1 psu is formed when the vertical advection is treated by the standard central-differencing advection scheme. The problem is considerably reduced either by increasing the vertical resolution of the numerical grid, or by switching to a higher-order upwind-weighted scheme for vertical advection. This note stresses the need for a careful consideration of vertical discretization even in typical high-resolution ocean general circulation models (OGCMs). Particular attention is needed for studying heat and salt budgets or transports of biogeochemical tracers.  相似文献   
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E01 VLTI‐PRIMA Fringe Tracking Testbed E02 The Fringe and Flexure Tracking System for the LBT interferometric camera LINC‐NIRVANA E03 GRAVITY: The AO assisted, two object beam combiner instrument for the VLTI E04 (Re)Solving the dynamic atmospheres of carbon‐rich giants E05 Do's and Don'ts of MIDI Data‐reduction E06 Bispectrum speckle imaging of the ultracompact HII region K3‐50A E07 Differential astrometry and astrometric planet searches with the VLTI E08 First AU‐scale observations of V1647 Ori: The outbursting young star in the McNeil's Nebula E09 Mid‐infrared imaging at the VLTI: An APreS‐MIDI image reconstruction study E10 VLTI/MIDI observation of the silicate carbon star Hen 38 (IRAS08002‐3803): Silicate dust reservoir spatially resolved for the first time E11 Mid‐infrared spectro‐interferometric observation of the Mira variable RR Sco with the VLTI/MIDI instrument E12 Scientific Prospects for VLTI in the Galactic Centre: Getting to the Schwarzschild Radius E13 VLTI near‐infrared observations of the stellar multiple system δ Velorum E14 The first VLTI observations of the Galactic Center E15 Bispectrum speckle interferometry of the massive protostellar outflow source IRAS 23151+5912 E16 Interferometric Observations of Infrared Companions with MIDI E17 Evolution and radial distribution of dust in the inner 1‐10A.U. of circumstellar disks around low‐mass young stellar objects. E18 Near‐infrared Interferometry with the AMBER Instrument of the VLTI E19 APreS‐MIDI ‐ Interferometic Imaging in the Mid‐Infrared E20 Mining the sky: Selection of extragalactic targets for interferometric observations  相似文献   
353.
As a common constituent of metamorphic assemblages, rutile provides constraints on the timing and conditions of rock transformation at high resolution. However, very little is known about the links between trace element mobility and rutile microstructures that result from synmetamorphic deformation. To address this issue, here we combine in situ LA-ICP-MS and sensitive high-resolution ion microprobe trace element data with electron back-scatter diffraction microstructural analyses to investigate the links between rutile lattice distortions and Zr and U–Pb systematics. Furthermore, we apply this integrated approach to constrain further the temperature and timing of amphibolite facies metamorphism and deformation in the Bergen Arcs of southwestern Norway. In outcrop, the formation of porphyroblastic rutile in dynamically hydrated leucocratic domains of otherwise rutile-poor statically hydrated amphibolite provides key contextual information on both the ambient conditions of hydration and deformation and the composition of the reactive fluid. Rutile in amphibolite recorded ambient metamorphic temperatures of ~590–730°C during static hydration of the granulitic precursor. By contrast, rutile from leucocratic domains in the directly adjacent shear zone indicates that deformation was accompanied by a localized increase in temperature. These higher temperatures are recorded in strain-free rutile (~600–860°C) and by Zr concentration measurements on low-angle boundaries and shear bands (620–820°C). In addition, we also observe slight depletions of Zr and U along rutile low-angle boundaries relative to strain-free areas in deformed grains from the shear zone. This indicates that crystal–plastic deformation facilitated the compositional re-equilibration of rutile upon cooling to slightly below the peak temperature of deformation. Cessation of deformation at mid-crustal conditions near ~600°C is recorded by late stage growth of small (<150 µm) rutile in the high-strain zones. U–Pb age data obtained from the strain-free and distorted rutile grains cluster in distinct populations of 437.4 ± 2.7 Ma and c. 405–410 Ma, respectively. These different ages are interpreted to reflect the difference in closure for thermally induced Pb diffusion between undeformed and deformed rutile during post-deformation exhumation and cooling. Thus, our results provide a reconstruction of the thermochronological history of the amphibolite facies rocks of the Lindås Nappe and highlight the importance of integration of microstructural data during application of thermometers and geochronometers.  相似文献   
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On reliable data-driven partial GNSS ambiguity resolution   总被引:1,自引:1,他引:0  
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356.
Until recently, the British‐Irish Ice Sheet (BIIS) was thought to have reached no farther than a mid‐continental shelf position in the Hebrides Sector, NW Britain, during the last glaciation (traditional model). However, recent discovery of widespread shelf‐edge moraines in this sector has led to a suggestion of much more extensive ice (Atlantic Shelf model). The position of the St Kilda archipelago, approximately mid‐way between the Outer Hebrides and the continental shelf edge, makes it ideal as an onshore location to test which of the two competing models is more viable. To this end, we (i) reassessed the characteristics, stratigraphy and morphology of the Quaternary sediments exposed on the largest island (Hirta), and (ii) applied time‐dependent 2D numerical modelling of possible glacier formation on Hirta. Instead of three glaciations (as previously suggested), we identified evidence of only two, including one of entirely local derivation. The numerical model supports the view that this glaciation was in the form of two short glaciers occupying the two valleys that dominate Hirta. The good state of preservation of the glacial sediments and associated moraine of this local glaciation indicate relatively recent formation. In view of the low inferred equilibrium line altitude of the glacier associated with the best morphological evidence (~120 m), considerable thickness of slope deposits outside the glacial limits and evidence of only one rather than two tills, a Late Devensian rather than Younger Dryas age is preferred for this glaciation. Re‐examination of the submarine moraine pattern from available bathymetry suggests that the ice sheet was forced to flow around St Kilda, implying that the ice was of insufficient thickness to overrun the islands. Accepting this leaves open the possibility that a St Kilda nunatak supported local ice while the ice sheet extended to the continental shelf edge.  相似文献   
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