Wind-generated waves in Hurricane Juan   总被引：3，自引：0，他引：3  

Fumin Xu  Will Perrie  Bechara Toulany  Peter C. Smith 《Ocean Modelling》2007,16(3-4):188-205

We present numerical simulations of the ocean surface waves generated by hurricane Juan in 2003 as it reached its mature stage (travelling from deep waters off Bermuda to Nova Scotia and making landfall near Halifax) using SWAN (v.40.31) nested within WAVEWATCH-III (v.2.22; denoted WW3) wave models, implemented on multiple-nested domains. As for all storm-wave simulations, spectral wave development is highly dependent on accurate simulations of storm winds during its life cycle. Due to Juan’s rapid translation speed (accelerating from 2.28 m s⁻¹ on 27 September, 1200 UTC to 20 m s⁻¹ on 29 September, 1200 UTC), an interpolation method is developed to blend observed hurricane winds with numerical weather prediction (NWP) model winds accurately. Wave model results are compared to in situ surface buoys and ADCP wave data along Juan’s track. At landfall, Juan’s maximum waves are mainly swell-dominated and peak waves lag the occurrence of the maximum winds. We explore the influence of surface waves on the wind and show that the accuracy of the wave simulation is enhanced by introducing swell and Stokes drift feedback mechanisms to modify the winds, and by limiting the peak drag coefficient under high wind conditions, in accordance with recent theoretical and experimental results.  相似文献   

Science-based and stakeholder-driven marine protected area network planning: A successful case study from north central California     

Mary Gleason  Scott McCreary  Melissa Miller-Henson  John Ugoretz  Evan Fox  Matt Merrifield  Will McClintock  Paulo Serpa  Kathryn Hoffman 《Ocean & Coastal Management》2010,53(2):52-68

The planning process for California's Marine Life Protection Act in north central California represents a case study in the design of a regional component of a statewide network of marine protected areas (MPAs) for improved ecosystem protection. We describe enabling factors, such as a legislative mandate, political will, and adequate capacity and funding that fostered a successful planning process. We identify strategic principles that guided the design of a transparent public planning process that delivered regional MPA network proposals, which both met science guidelines and achieved a high level of support among stakeholders. We also describe key decision support elements (spatial data, planning tools, and scientific evaluation) that were essential for designing, evaluating, and refining alternative MPA network proposals and for informing decision-makers.  相似文献   

Soil-precipitation feedbacks during the South American Monsoon as simulated by a regional climate model   总被引：1，自引：0，他引：1  

Anna A. Sörensson  Claudio G. Menéndez  Patrick Samuelsson  Ulrika Willén  Ulf Hansson 《Climatic change》2010,98(3-4):429-447

We summarize the recent progress in regional climate modeling in South America with the Rossby Centre regional atmospheric climate model (RCA3-E), with emphasis on soil moisture processes. A series of climatological integrations using a continental scale domain nested in reanalysis data were carried out for the initial and mature stages of the South American Monsoon System (SAMS) of 1993–92 and were analyzed on seasonal and monthly timescales. The role of including a spatially varying soil depth, which extends to 8 m in tropical forest, was evaluated against the standard constant soil depth of the model of about 2 m, through two five member ensemble simulations. The influence of the soil depth was relatively weak, with both beneficial and detrimental effects on the simulation of the seasonal mean rainfall. Secondly, two ensembles that differ in their initial state of soil moisture were prepared to study the influence of anomalously dry and wet soil moisture initial conditions on the intraseasonal development of the SAMS. In these simulations the austral winter soil moisture initial condition has a strong influence on wet season rainfall over feed back upon the monsoon, not only over the Amazon region but in subtropical South America as well. Finally, we calculated the soil moisture–precipitation coupling strength through comparing a ten member ensemble forced by the same space–time series of soil moisture fields with an ensemble with interactive soil moisture. Coupling strength is defined as the degree to which the prescribed boundary conditions affect some atmospheric quantity in a climate model, in this context a quantification of the fraction of atmospheric variability that can be ascribed to soil moisture anomalies. La Plata Basin appears as a region where the precipitation is partly controlled by soil moisture, especially in November and January. The continental convective monsoon regions and subtropical South America appears as a region with relatively high coupling strength during the mature phase of monsoon development.  相似文献   

Electrical conductivity measurements on synthetic olivines and on olivine,enstatite and diopside from Dreiser Weiher,Eifel (Germany) under defined thermodynamic activities as a function of temperature and pressure     

E. Hinze  G. Will  L. Cemič 《Physics of the Earth and Planetary Interiors》1981,25(3):245-254

Results of electrical conductivity measurments on synthetic olivines of the system Mg₂SiO₄Fe₂SiO₄ and on minerals of Dreiser Weiher peridotite nodule Ib-8 (Eifel, Germany) are discussed in relation to the measuring procedure and to the variation of thermodynamic parameters.The measurements were performed in solid state high-pressure vessels between 340 and 1100°C and at a pressure of 10 kbar. It is shown that for ternary olivines and for pyroxenes, the control of two further variables, like the chemical activities of the components, is needed besides temperature and pressure control. The experimental set-up for the control of chemical activities and oxygen partial pressure is shown. From the slopes of the lines of log σ against 1/T the activation energies were calculated. Though in most cases the same oxygen fugacity ?_O2 is applied, the results reveal different values for synthetic and natural samples since the chemical activities of SiO₂ are different.  相似文献   

Electrical conductivity measurements on olivines and pyroxenes under defined thermodynamic activities as a function of temperature and pressure     

G. Will  L. Cemič  E. Hinze  K. -F. Seifert  R. Voigt 《Physics and Chemistry of Minerals》1979,4(2):189-197

Electrical conductivities of Ni₂SiO₄, Fe₂SiO₄, and MgSiO₃ were measured on synthetic powders in the temperature range 340° to 1,100° C and at pressures up to 20 kbars. For ternary compounds such as olivines and pyroxenes the control of two further variables, like the chemical activities of two components are needed, besides temperature and pressure. The activities of the corresponding binary oxides were controlled by equilibrating the samples with their neighbour-phases. Control of the oxygen partial pressure was achieved by buffer techniques. From the slopes of the lg σ vs. 1/T lines the activation energies were calculated for 10 kbar: 0.56 eV and 2.7 eV for Ni₂SiO₄ in equilibrium with SiO₂ and Ni/NiO-buffer for the temperature range 500°–800°C and 800°–1,000°C resp. 0.52 eV for Fe₂SiO₄ in equilibrium with SiO₂ and metallic iron, and 0.38 eV in equilibrium with SiO₂ and magnetite; 1.11 eV for MgSiO₃ in equilibrium with SiO₂, and 1.25 eV in equilibrium with Mg₂SiO₄.  相似文献   

Influence of oxygen partial pressure on the Mg/Fe distribution in olivines     

G. Will  G. Nover 《Physics and Chemistry of Minerals》1979,4(2):199-208

The dependence of Mg/Fe ordering on oxygen partial pressure in natural olivine crystals of volcanic origin has been studied by X-ray diffraction. Two natural crystals with 10% and 12% fayalite have been investigated and the atomic positions, anisotropic temperature factors, extinction coefficients and site occupancies have been refined, reaching R-values of 2.2%. After subjecting the crystals to oxygen partial pressures of 10^?16 bar and 10^?21 bar the crystals were studied again. In total six crystals were studied and the distribution coefficients K _D determined. The natural untreated crystals had K _D=1.09 and 1.06, e.g., a slight preference of Fe in (M1). p(O₂) of 10^?16 bar increased the ordering of Fe in (M1) to K _D=1.2, while p(O₂)=10^?21 bar reversed K _D to 0.8 with ordering of Fe in (M2). These experiments suggest that Mg/Fe ordering in olivines is primarily determined by the prevailing oxygen partial pressure.  相似文献   

On journal publication and professional responsibilities     

Stephen K Donovan  Will Hughes 《Area》2004,36(3):325-326

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Bond-valence methods for pK_a prediction: critical reanalysis and a new approach     

Barry R. Bickmore  Christopher J. Tadanier  Will D. Monn 《Geochimica et cosmochimica acta》2004,68(9):2025-2042

Bond-valence methods for the prediction of (hydr)oxide solution monomer and surface functional group acidity constants are examined in light of molecular structures calculated using ab initio methods. A new method is presented that is based on these calculated structures, and it is shown that previously published methods have neglected one or more of four essential features of a generalized model. First, if the apparent pK_a values of solution monomers are to be used to predict intrinsic pK_a values of surface functional groups, similar electrostatic corrections must be applied in both cases. In surface complexation models, electrostatic corrections are applied by representing a charged surface as a uniform plane of charge density, and an analogous correction can be made to solution monomers by treating them as charged spheres. Second, it must be remembered that real surfaces and real monomers are not homogeneous planes or spheres. Rather, charge density is distributed rather unevenly, and a further electrostatic correction (which is often quite large) must be made to account for the proximity of electron density to the point of proton attachment. Third, the unsaturated valence of oxygen atoms in oxyacids, hexaquo cations, and oxide surfaces is strongly correlated with acidity after electrostatic corrections are made. However, calculation of unsaturated valence for oxyacids and oxide surfaces must be based on realistic MeO bond lengths (taking into account bond relaxation), which can be obtained from ab initio structure optimizations. Finally, unsaturated valence must be divided between possible bonds (four for oxygen atoms) to reflect the fact that O-H bonds are localized to particular regions of the O atoms.Empirical models that take all these factors into account are presented for oxyacids and hexaquo cations. These models are applied to the gibbsite (100), (010), (001), and cristobalite (100) surfaces, and it is demonstrated that the model for oxyacids predicts reasonable intrinsic pK_a values for oxide surfaces. However, the prediction of surface pK_a values is complex, because the protonation state of one functional group affects the pK_a values of neighboring groups. Therefore, calculations of larger periodic systems, progressively protonated and reoptimized, are needed.  相似文献   

Comparison of neutron and X-ray diffraction in texture analysis of deformed carbonate rocks     

H.R. Wenk  H. Kern  W. Schaefer  G. Will 《Journal of Structural Geology》1984,6(6):687-692

The paper compares pole figure determinations with neutron diffraction and X-ray diffraction on experimentally deformed carbonate rocks, a coarse grained marble and fine grained limestone. Neutron diffraction enables determination of complete pole figures on a single spherical specimen and is advantageous for coarse grained materials. Results obtained with both diffraction techniques agree satisfactorily, although uncertainties introduced by counting statistics are more serious for neutrons than for X-rays. Continuous detectors add new possibilities which are still little explored.  相似文献   

The 2dF Galaxy Redshift Survey: the luminosity function of cluster galaxies     

Roberto De Propris  Matthew Colless  Simon P. Driver  Warrick Couch  John A. Peacock  Ivan K. Baldry  Carlton M. Baugh  Joss Bland-Hawthorn  Terry Bridges  Russell Cannon  Shaun Cole  Chris Collins  Nicholas Cross  Gavin B. Dalton  George Efstathiou  Richard S. Ellis  Carlos S. Frenk  Karl Glazebrook  Edward Hawkins  Carole Jackson  Ofer Lahav  Ian Lewis  Stuart Lumsden  Steve Maddox  Darren S. Madgwick  Peder Norberg  Will Percival  Bruce Peterson  Will Sutherland  Keith Taylor 《Monthly notices of the Royal Astronomical Society》2003,342(3):725-737

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