The pre-main-sequence binary HK Ori: spectro-astrometry and EXPORT data     

D. Baines  R. D. Oudmaijer  A. Mora  C. Eiroa  John M. Porter  B. Merín  B. Montesinos  D. de Winter  A. Cameron  J. K. Davies  H. J. Deeg  R. Ferlet  C. A. Grady  A. W. Harris  M. G. Hoare  K. Horne  S. L. Lumsden  L. F. Miranda  A. Penny  A. Quirrenbach 《Monthly notices of the Royal Astronomical Society》2004,353(2):697-704

  相似文献   

Estimating Ground-Water Recharge from Streamflow Hydrographs for a Small Mountain Watershed in a Temperate Humid Climate, New Hampshire, USA   总被引：7，自引：0，他引：7  

David P. Mau  Thomas C. Winter 《Ground water》1997,35(2):291-304

  相似文献   

Near-IR Reflectance Spectroscopy of 433 Eros from the NIS Instrument on the NEAR Mission: I. Low Phase Angle Observations     

J.F. Bell IIIN.I. Izenberg  P.G. LuceyB.E. Clark  C. PetersonM.J. Gaffey  J. JosephB. Carcich  A. HarchM.E. Bell  J. WarrenP.D. Martin  L.A. McFaddenD. Wellnitz  S. MurchieM. Winter  J. VeverkaP. Thomas  M.S. RobinsonM. Malin  A. Cheng 《Icarus》2002,155(1):119-144

From February 13 to May 13, 2000, the near-infrared spectrometer (NIS) instrument on the Near Earth Asteroid Rendezvous (NEAR) spacecraft obtained more than 200,000 spatially resolved 800- to 2500-nm reflectance spectra of the S-type asteroid 433 Eros. An important subset of the spectra was obtained during a unique opportunity on February 13 and 14, when the NEAR spacecraft flew directly through the 0° phase angle point between Eros and the Sun just prior to the orbital insertion maneuver. This low phase flyby (LPF) dataset consists of ∼2000 spectra of the northern hemisphere of Eros, obtained from 1° to 47° phase angle and at spatial resolutions of between 6×12 km to 1.25×2.50 km per spectrum. The spectra were calibrated to radiance factor (I/F, where I=observed radiance and πF=solar input radiance) and then photometrically corrected to normal albedo. The average northern hemisphere spectrum of Eros is similar to the asteroid's unresolved telescopic spectrum and exhibits absorption features near 1000 nm (Band I) and 2000 nm (Band II) consistent with an orthopyroxene to orthopyroxene+olivine (opx+ol) mixing ratio of approximately 0.38±0.08. The ensemble of NIS LPF spectra falls primarily within the S(IV) to upper S(III) fields of the Gaffey et al. (1993) S-asteroid classification scheme and exhibits Band I and Band II properties similar to those of ordinary chondrite meteorites. While some small spatially coherent spectral variations have been detected, neither the opx/opx+ol) mixing ratio nor other spectral parameters vary spatially by more than ∼1σ across the entire northern hemisphere of the asteroid, suggesting a remarkable homogeneity of the composition and mineralogy of the uppermost regolith. Spectral mixture modeling suggests that the presence of glass and/or a reddening agent like nanophase iron, likely formed from exposure of the regolith to the space environment, is a component of the surface of Eros. Reddening and darkening components could also explain the dissimilarity in overall spectral slope and albedo between Eros and other S(IV) asteroids and ordinary chondrite meteorites. The largest (but still weak) spectral variations across the surface are seen in the depths of Band I and Band II, which are greatest in and around the largest craters and at the 0° longitude “nose” of the asteroid, and in the Band II/Band I area ratio between the large impact craters Psyche and Himeros. These subtle NIS spectral variations are usually associated with albedo and surface slope variations seen in NEAR imaging and topographic data and appear to be related to downslope movement of regolith materials.  相似文献   

Normalized Mahalanobis distance for comparing process-based stochastic models   总被引：1，自引：1，他引：0  

C. L. Winter 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(6):917-923

We investigate a method based on normalized Mahalanobis distance, D, for comparing the performance of alternate stochastic models of a given environmental system. The approach is appropriate in cases where data are too limited to calculate either likelihood ratios or Bayes factors. Computational experiments based on simulated data are used to evaluate D’s ability to identify a “true” model and to single out good models. Data are simulated for two populations with different “signal–noise ratios” (S/N) The expected value of D is decomposed to evaluate the effects of normalization, model bias, and model correlation structure on D’s discriminatory power. Normalization compensates for the advantage one model may have over another due to technical features of its hypothesized correlation structure. The relative effects of bias and correlation structure vary with S/N, model bias being most important when S/N is relatively high and correlation structure increasing in importance as S/N decreases.  相似文献   

Exploring German Bight coastal morphodynamics based on modelled bed shear stress     

Frank Kösters  Christian Winter 《Geo-Marine Letters》2014,34(1):21-36

The prediction of large-scale coastal and estuarine morphodynamics requires a sound understanding of the relevant driving processes and forcing factors. Data- and process-based methods and models suffer from limitations when applied individually to investigate these systems and, therefore, a combined approach is needed. The morphodynamics of coastal environments can be assessed in terms of a mean bed elevation range (BER), which is the difference of the lowest to highest seabed elevation occurring within a defined time interval. In this study of the coastal sector of the German Bight, North Sea, the highly variable distribution of observed BER for the period 1984–2006 is correlated to local bed shear stresses based on hindcast simulations with a well-validated high-resolution (typically 1,000 m in coastal settings) process-based numerical model of the North Sea. A significant correlation of the 95th percentile of bed shear stress and BER was found, explaining between 49 % and 60 % of the observed variance of the BER under realistic forcing conditions. The model then was applied to differentiate the effects of three main hydrodynamic drivers, i.e. tides, wind-induced currents, and waves. Large-scale mapping of these model results quantify previous qualitative suggestions: tides act as main drivers of the East Frisian coast, whereas waves are more relevant for the morphodynamics of the German west coast. Tidal currents are the main driver of the very high morphological activity of the tidal channels of the Ems, Weser and Elbe estuaries, the Jade Bay, and tidal inlets between the islands. This also holds for the backbarrier tidal flats of the North Frisian Wadden Sea. The morphodynamics of the foreshore areas of the barrier island systems are mainly wave-driven; in the deeper areas tides, waves and wind-driven currents have a combined effect. The open tidal flats (outer Ems, Neuwerker Watt, Dithmarschen Bight) are affected by a combination of tides, wind-driven currents and waves. Model performance should be measurably improved by integrating the roles of other key drivers, notably sediment dynamics and salt marsh stabilisation.  相似文献   

A New Framework for Solving the Spatial Network Problems Based on Line Graphs     

Javad Saberian  Mohammad Reza Malek  Stephan Winter  Majid Hamrah 《Transactions in GIS》2014,18(5):767-782

In this article we define inverse line graphs of directed graphs as a new framework for solving some classical network analysis problems. The extraction method and theories of inverse line graphs are explained in this article. It is shown that by changing the analysis space from the original directed graph to the inverse line graph, complex problems can be changed into simpler problems. We show the usefulness of the proposed framework in two particular applications: shortest path computations and the more general route planning. Considering the implementation result, we expect that this framework could be used in many more network analysis problems.  相似文献   

Three-dimensional cathodoluminescence imaging and electron backscatter diffraction: tools for studying the genetic nature of diamond inclusions     

D. F. Wiggers de Vries  M. R. Drury  D. A. M. de Winter  G. P. Bulanova  D. G. Pearson  G. R. Davies 《Contributions to Mineralogy and Petrology》2011,161(4):565-579

As a step towards resolving the genesis of inclusions in diamonds, a new technique is presented. This technique combines cathodoluminescence (CL) and electron backscatter diffraction (EBSD) using a focused ion beam–scanning electron microscope (FIB–SEM) instrument with the aim of determining, in detail, the three-dimensional diamond zonation adjacent to a diamond inclusion. EBSD reveals that mineral inclusions in a single diamond have similar crystallographic orientations to the host, within ±0.4°. The chromite inclusions record a systematic change in Mg# and Cr# from core to the rim of the diamond that corresponds with a ~80°C decrease of their formation temperature as established by zinc thermometry. A chromite inclusion, positioned adjacent to a boundary between two major diamond growth zones, is multi-faceted with preferred octahedral and cubic faces. The chromite is surrounded by a volume of non-luminescent diamond (CL halo) that partially obscures any diamond growth structures. The CL halo has apparent crystallographic morphology with symmetrically oriented pointed features. The CL halo is enriched in ~200 ppm Cr and ~80 ppm Fe and is interpreted to have a secondary origin as it overprints a major primary diamond growth structure. The diamond zonation adjacent to the chromite is complex and records both syngenetic and protogenetic features based on current inclusion entrapment models. In this specific case, a syngenetic origin is favoured with the complex form of the inclusion and growth layers indicating changes of growth rates at the diamond–chromite interface. Combined EBSD and 3D-CL imaging appears an extremely useful tool in resolving the ongoing discussion about the timing of inclusion growth and the significance of diamond inclusion studies.  相似文献   

Tomography of the Earth’s core using supernova neutrinos     

Manfred Lindner  Tommy Ohlsson  Ricard Toms  Walter Winter 《Astroparticle Physics》2003,19(6):755-770

We investigate the possibility to use the neutrinos coming from a future galactic supernova explosion to perform neutrino oscillation tomography of the Earth’s core. We propose to use existing or planned detectors, resulting in an additional payoff. Provided that all of the discussed uncertainties can be reduced as expected, we find that the average matter densities of the Earth’s inner and outer cores could be measured with a precision competitive with geophysics. However, since seismic waves are more sensitive to matter density jumps than average matter densities, neutrino physics would give partly complementary information.  相似文献   

Coal overburden. Geological characterization and premine planning: by Roy D. Merritt. Noyes Data Corporation, Park Ridge, NJ, U.S.A., 1983, viii + 343 pp., US $ 39.00 (clothbound)     

K. Winter 《International Journal of Coal Geology》1987,7(4)

  相似文献   

    

Christian Winter  Alexander Bartholom? 《Geo-Marine Letters》2006,26(5):303

  相似文献