Stellar and galactic environment survey (SAGE)     

M. A. Barstow  M. R. Burleigh  N. J. Bannister  J. S. Lapington  M. P. Kowalski  R. G. Cruddace  K. S. Wood  F. Auchere  M. F. Bode  G. E. Bromage  B. Gibson  A. C. Cameron  A. Cassatella  F. Delmotte  M.-F. Ravet  J. G. Doyle  C. S. Jeffery  B. Gaensicke  C. Jordan  N. Kappelmann  K. Werner  R. Lallement  D. de Martino  S. A. Matthews  K. J. H. Phillips  G. Del Zanna  M. Orio  E. Pace  I. Pagano  J. H. M. M. Schmitt  B. Y. Welsh 《Astrophysics and Space Science》2009,320(1-3):231-238

This paper describes a proposed high resolution soft X-ray and Extreme Ultraviolet (EUV) spectroscopy mission to carry out a survey of Stellar and Galactic Environments (SAGE). The payload is based on novel diffraction grating technology which has already been proven in a sub-orbital space mission and which is ready to fly on a satellite platform with minimal development. Much of the technical detail of the instrumentation has been reported elsewhere and we concentrate our discussion here on the scientific goals of a SAGE base-line mission, demonstrating the scientific importance of high resolution spectroscopy in the Extreme Ultraviolet for the study of stars and the local interstellar medium.  相似文献   

Stellar And Galactic Environment survey (SAGE)     

M. A. Barstow  M. P. Kowalski  R. G. Cruddace  K. S. Wood  F. Auchere  N. J. Bannister  M. F. Bode  G. E. Bromage  M. R. Burleigh  A. C. Cameron  A. Cassatella  F. Delmotte  J. G. Doyle  B. Gaensicke  B. Gibson  C. S. Jeffery  C. Jordan  N. Kappelmann  R. Lallement  J. S. Lapington  D. de Martino  S. A. Matthews  M. Orio  E. Pace  I. Pagano  K. J. H. Phillips  M.-F. Ravet  J. H. M. M. Schmitt  B. Y. Welsh  K. Werner  G. Del Zanna 《Experimental Astronomy》2009,23(1):169-191

This paper describes a proposed high resolution soft X-ray and Extreme Ultraviolet spectroscopy mission to carry out a survey of Stellar and Galactic Environments (SAGE). The payload is based on novel diffraction grating technology which has already been proven in a sub-orbital space mission and which is ready to fly on a satellite platform with minimal development. We discuss the goals of a SAGE base-line mission and demonstrate the scientific importance of high resolution spectroscopy in the Extreme Ultraviolet for the study of stars and the local interstellar medium.  相似文献   

Experiments using new initial soil moisture conditions and soil map in the Eta model over La Plata Basin     

Moira E. Doyle  Javier Tomasella  Daniel A. Rodriguez  Sin Chan Chou 《Meteorology and Atmospheric Physics》2013,121(3-4):119-136

An effort towards a more accurate representation of soil moisture and its impact on the modeling of weather systems is presented. Sensitivity tests of precipitation to soil type and soil moisture changes are carried out using the atmospheric Eta model for the numerical simulation of the development of a mesoscale convective system over northern Argentina. Modified initial soil moisture conditions were obtained from a hydrological balance model developed and running operationally at INPE. A new soil map was elaborated using the available soil profile information from Brazil, Paraguay, Uruguay, and Argentina and depicts 18 different soil types. Results indicate that more accurate initial soil moisture conditions and incorporating a new soil map with hydraulic parameters, more representative of South American soils, improve daily total precipitation forecasts both in quantitative and spatial representations.  相似文献   

Development and testing of a coupled ocean–atmosphere mesoscale ensemble prediction system     

Teddy R. Holt  James A. Cummings  Craig H. Bishop  James D. Doyle  Xiaodong Hong  Sue Chen  Yi Jin 《Ocean Dynamics》2011,61(11):1937-1954

A coupled ocean–atmosphere mesoscale ensemble prediction system has been developed by the Naval Research Laboratory. This paper describes the components and implementation of the system and presents baseline results from coupled ensemble simulations for two tropical cyclones. The system is designed to take into account major sources of uncertainty in: (1) non-deterministic dynamics, (2) model error, and (3) initial states. The purpose of the system is to provide mesoscale ensemble forecasts for use in probabilistic products, such as reliability and frequency of occurrence, and in risk management applications. The system components include COAMPS® (Coupled Ocean/Atmosphere Mesoscale Prediction System) and NCOM (Navy Coastal Ocean Model) for atmosphere and ocean forecasting and NAVDAS (NRL Atmospheric Variational Data Assimilation System) and NCODA (Navy Coupled Ocean Data Assimilation) for atmosphere and ocean data assimilation. NAVDAS and NCODA are 3D-variational (3DVAR) analysis schemes. The ensembles are generated using separate applications of the Ensemble Transform (ET) technique in both the atmosphere (for moving or non-moving nests) and the ocean. The atmospheric ET is computed using wind, temperature, and moisture variables, while the oceanographic ET is derived from ocean current, temperature, and salinity variables. Estimates of analysis error covariance, which is used as a constraint in the ET, are provided by the ocean and atmosphere 3DVAR assimilation systems. The newly developed system has been successfully tested for a variety of configurations, including differing model resolution, number of members, forecast length, and moving and fixed nest options. Results from relatively coarse resolution (～27-km) ensemble simulations of Hurricanes Hanna and Ike demonstrate that the ensemble can provide valuable uncertainty information about the storm track and intensity, though the ensemble mean provides only a small amount of improved predictive skill compared to the deterministic control member.  相似文献   

Temperature Inverted Haloclines Provide Winter Warm-Water Refugia for Manatees in Southwest Florida     

Bradley M. Stith  James P. Reid  Catherine A. Langtimm  Eric D. Swain  Terry J. Doyle  Daniel H. Slone  Jeremy D. Decker  Lars E. Soderqvist 《Estuaries and Coasts》2011,34(1):106-119

Florida manatees (Trichechus manatus latirostris) overwintering in the Ten Thousand Islands and western Everglades have no access to power plants or major artesian springs that provide warm-water refugia in other parts of Florida. Instead, hundreds of manatees aggregate at artificial canals, basins, and natural deep water sites that act as passive thermal refugia (PTR). Monitoring at two canal sites revealed temperature inverted haloclines, which provided warm salty bottom layers that generally remained above temperatures considered adverse for manatees. At the largest PTR, the warmer bottom layer disappeared unless significant salt stratification was maintained by upstream freshwater inflow over a persistent tidal wedge. A detailed three-dimensional hydrology model showed that salinity stratification inhibited vertical convection induced by atmospheric cooling. Management or creation of temperature inverted haloclines may be a feasible and desirable option for resource managers to provide passive thermal refugia for manatees and other temperature sensitive aquatic species.  相似文献   

The photometric method of extrasolar planet detection revisited     

Alan Hale  Laurance R. Doyle 《Astrophysics and Space Science》1994,212(1-2):335-348

We investigate the geometry concerning the photometric method of extrasolar planet detection, i.e., the detection of dimunition of a parent star's brightness during a planetary transit. Under the assumption that planetary orbital inclinations can be defined by a Gaussian with a of 10° centered on the parent star's equatorial plane, Monte Carlo simulations suggest that for a given star observed at an inclination of exactly 90°, the probability of at least one Earth-sized or larger planet being suitably placed for transits is approximately 4%. This probability drops to 3% for a star observed at an inclination of 80°, and is still 0.5% for a star observed at an inclination of 60°. If one can select 100 stars with a pre-determined inclination 80°, the probability of at least one planet being suitably configured for transits is 95%. The majority of transit events are due to planets in small-a orbits similar to the Earth and Venus; thus, the photometric method in principle is the method best suited for the detection of Earthlike planets.The photometric method also allows for testing whether or not planets can exist within binary systems. This can be done by selecting binary systems observed at high orbital inclinations, both eclipsing binaries and wider visual binaries. For a real-world example, we look at the Centauri system (i = 79°.2). If we assume that the equatorial planes of both components coincide with the system's orbital plane, Monte Carlo simulations suggest that the probability of at least one planet (of either component) being suitably configured for transits is approximately 8%.In conclusion, we present a non-exhaustive list of solar-type stars, both single and within binary systems, which exhibit a high equatorial inclination. These objects may be considered as preliminary candidates for planetary searches via the photometric method.Paper presented at the Conference onPlanetary Systems: Formation, Evolution, and Detection held 7–10 December, 1992 at CalTech, Pasadena, California, U.S.A.  相似文献   

Gravel-bed Rivers V: Edited by M. Paul Mosley, 2001, New Zealand Hydrological Society, Wellington, New Zealand. Hardcover, 642 pp., ISBN Number 0-473-07486-9. Price: US $95.00     

Martin W. Doyle   《Geomorphology》2004,57(3-4):437-439

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A contribution to the crystal chemistry of the voltaite group: solid solutions, Mössbauer and infrared spectra, and anomalous anisotropy     

Juraj Majzlan  Hannes Schlicht  Maria Wierzbicka-Wieczorek  Gerald Giester  Herbert Pöllmann  Beatrix Brömme  Stephen Doyle  Gernot Buth  Christian Bender Koch 《Mineralogy and Petrology》2013,107(2):221-233

Voltaite is a mineral of fumaroles, solfatares, coal-fire gas vents, and acid-mine drainage systems. The nominal composition is K₂Fe₅ ²⁺Fe₃ ³⁺Al(SO₄)₁₂·18H₂O and the nominal symmetry is cubic, $Fd\overline{3}c$ . The tetragonal (I4₁/acd) superstructure of voltaite is known as the mineral pertlikite. In this study, we investigated 22 synthetic voltaite samples in which Fe²⁺ was partially or completely replaced by Mg, Zn, Mn, or Cd, by single-crystal and powder X-ray diffraction (both in-house and synchrotron). Two samples contained NH₄ ⁺ instead of K⁺. The structure of voltaite is based on a framework defined by kröhnkite-like heteropolyhedral chains which host both M³⁺ and M²⁺ in octahedral coordination. Unit cell dimensions of the end-members scale almost linearly with the size of M²⁺. In the Fe²⁺-Mg-Zn solid solutions, the Fe²⁺-Mg and Fe²⁺-Zn solutions are linear (ideal) in terms of their lattice-parameter variations. The Mg-Zn solid solution, however, is strongly non-ideal. A detailed analysis of the topology of the chains showed that this behavior originates in expansion and contraction of individual M²⁺-O bonds within the chains. In the Mg-Zn solid solution, some of the M²⁺-O bonds expand while none contract. In the other solid solutions, expansion of some M²⁺-O bonds is always compensated by contraction of the other ones. Parts of the nominally cubic crystals are optically anisotropic and their symmetry is found to be tetragonal by single crystal X-ray diffraction measurements. The coexistence of cubic and tetragonal sectors within a single crystal without any detectable difference in their chemical composition is difficult to explain in terms of growth of such composite crystals. Mössbauer and infrared spectra collected on our synthetic crystals conform with previously published data.  相似文献   

Seismic velocities from explosions off the central coast of New South Wales     

H. A. Doyle  R. Underwood  E. J. Polak 《Australian Journal of Earth Sciences》2013,60(2):355-372

Travel times from explosions fired on the continental shelf off the central coast of New South Wales were observed at permanent stations and spreads of seismic exploration instruments, and combined with existing results to give a seismic crustal profile across part of southeastern Australia. An intermediate layer, dipping to the southwest, underlies the surface rocks and has a P velocity of about 6–52 km./sec. Beneath Sydney, its top may either be in contact with the basin sediments at a depth of about 5 km., or separated from them by a wedge of a few kilometres of 6 km./sec. material. The Mohorovi?i? discontinuity (M) is at a depth of 25 km., dips to the southwest at about 4 degrees, and the velocity under it is about 7.86 km./sec. The depth to the top of the intermediate layer under the Snowy Mountains is about 20 km., and the revised depth to M is about 42 km. M dips at about 2° to the southwest in this region, and the velocity at the top of the mantle is 8.1 km./sec.  相似文献   

Radiocarbon-dated ferricrete provides a record of natural acid rock drainage and paleoclimatic changes     

G. Furniss  N. W. Hinman  G. A. Doyle  D. D. Runnells 《Environmental Geology》1999,37(1-2):102-106

 Ancient deposits of ferricrete (stratified iron oxyhydroxide or clastic sediment cemented by stratified iron oxyhydroxide) are present in headwater streams draining an historic mining district in the Rocky Mountains, USA. These deposits, which form under conditions of low pH and high metal concentrations, are present in streams draining many other mineralized areas. Radiocarbon dating of wood fragments entombed within the ferricrete indicates dates of deposition as old as 8840±50 years before present (b.p.). The ferricrete deposits provide evidence that natural, metal-rich acid rock drainage has been occurring in this mineralized region for thousands of years, due to the weathering and oxidation of exposed or near-surface massive sulfide ore deposits. The dating and chemical composition of the ferricrete deposits have applications to the environmental remediation of historic mining sites and to environmental issues related to natural background chemistry. In addition, the radiocarbon dates of the ferricrete deposits correlate closely with warm–wet periods in the Holocene record, showing that ferricrete deposits may represent a previously untapped source of paleoclimatic information. Received: 6 October 1997 · Accepted: 23 March 1998  相似文献