LETTERS TO THE PRESIDENT OF THE ASSOCIATION     

Grant W. Miller  Fred E. Dohrs  Keith D. Harries  Glenn T. Trewartha  Wolf Roder  James S. Ward  Morton D. Winsberg  Bryce Decker  Thomas J. Wilbanks 《The Professional geographer》1973,25(4):383-390

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SOIL COMPACTION AND RECREATIONAL USE     

Robert M. Ward  Richard C. Berg 《The Professional geographer》1973,25(4):369-372

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Asteroid impact tsunami of 2880 March 16   总被引：1，自引：0，他引：1  

Steven N. Ward  Erik Asphaug 《Geophysical Journal International》2003,153(3):F6-F10

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Lucifers,a photoelectric radial-velocity spectrometer     

L. C. Watson  J. B. Hearnshaw  Donna-Maree Ward 《Astrophysics and Space Science》1994,218(2):187-203

A spectrometer dedicated to the measurement of stellar radial velocities has been developed at the University of Canterbury and the Mt John University Observatory. The spectrometer scans a spectrum from the Observatory's 1-metre McLellan reflecting telescope and fibre-fed échelle with an oscillating mask having 2447 rectangular slots representing absorption lines in the spectrum of the star Centauri A covered by the wavelength range 397 to 570 nm in orders 40 to 58 of the spectrograph and measures the light passing through the mask as a function of mask position. A dedicated computer constructs a cross-correlation function to which a Gaussian distribution function is fitted. The difference between the radial velocities of a star and a zero-velocity reference spectrum provided by a hollow-cathode iron emission lamp is calculated from the Gaussian parameters. The sources of random error in the system are discussed and its magnitude for stars of spectral types F0 to M3.5 is estimated. Systematic errors in the system are also discussed.  相似文献   

Numerical modeling of the June 24, 2015, Hongyanzi landslide generated impulse waves in Three Gorges Reservoir,China   总被引：1，自引：0，他引：1  

Lili Xiao  Jiajia Wang  Steven N Ward  Lixia Chen 《Landslides》2018,15(12):2385-2398

Subaerial landslides falling into confined water bodies often generate impulsive waves. Damaging landslide tsunamis in Three Gorges Reservoir, China, have struck several times in the last 15 years. On June 24, 2015, a 23?×?10⁴ m³ slope failure occurred on the east bank of the Daning River opposite Wushan Town. The sliding mass intruded into the Three Gorges Reservoir and initiated a reservoir tsunami that resulted in two deaths and significant damage to shipping facilities. A post-event survey revealed the landslide geometry and wave run-up distribution, while an eyewitness video captured most of the landslide motion. Employing these firm constraints, we applied the Tsunami Squares method to simulate the 2015 Hongyanzi landslide and tsunami. The simulation revealed that the landslide experienced a progressive failure in the first few seconds and impacted the water with a maximum velocity of ~?16 m/s. The initial wave propagated to the opposite shore in an arch shape, and the water surface reached a maximum amplitude of ~?11 m near the landslide. Wave amplitude-time curves at four points on the river cross section show that the initial wave reached Wushan town in about 50 s with an average wave velocity of ~?30 m/s. The maximum wave run-ups on the shoreline opposite the landslide are around 6 m and attenuate to less than 1 m beyond 2-km distance. The landslide simulation matches the observed geological profile and the eyewitness video, and the numerical results coincide with the observed wave run-up heights. Nearly 80% of landslide energy is lost due to frictional resistances, but the remaining fraction imparted to the tsunami carried catastrophic consequences to a large region. The numerical results emphasize the efficiency and accuracy of Tsunami Squares method for a “Quick Look” simulation of a potential landslide.  相似文献   

Community responses and adaptation strategies toward flood hazard in Jakarta,Indonesia     

Marfai  Muh Aris  Sekaranom  Andung Bayu  Ward  Philip 《Natural Hazards》2015,75(2):1127-1144

Natural Hazards - Jakarta, as the capital of the Republic of Indonesia, has long been known to be at risk from flood hazard. It is increasingly recognized that community responses and adaptation...  相似文献   

Enrichment of U–Se–Mo–Re–V in coals preserved within marine carbonate successions: geochemical and mineralogical data from the Late Permian Guiding Coalfield,Guizhou, China     

Shifeng Dai  Vladimir V. Seredin  Colin R. Ward  James C. Hower  Yunwei Xing  Weiguo Zhang  Weijiao Song  Peipei Wang 《Mineralium Deposita》2015,50(2):159-186

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Monosulfidic black ooze accumulations in sediments of the Geographe Bay area, Western Australia     

N.J. Ward  R.T. Bush 《Marine pollution bulletin》2010,60(11):2130-2136

Mobilisation of sedimentary monosulfidic black ooze (MBO) may result in rapid deoxygenation and acidification of surface waters, and release of potentially toxic metals. This study examines the extent and nature of MBO accumulation in the Geographe Bay area, Western Australia. MBO accumulations were found to be widespread in benthic sediments of the Geographe Bay area with acid-volatile sulfide (AVS) contents as high as 320 μmol g⁻¹. The MBO materials often had unusually high dissolved sulfide (S^−II) concentrations in their pore-waters (up to 610 mg L⁻¹) and elevated elemental sulfur (S⁰) contents (up to 51 μmol g⁻¹). Dissolved S^−II is able to accumulate due to limited iron availability and S⁰ is largely its partial oxidation product. The availability of organic carbon and Fe limited MBO accumulation at many sites. A comparison of AVS and simultaneously extracted metal (SEM) concentrations has shown that metals are likely to be bound in sulfide complexes.  相似文献   

Characterizing hyporheic transport processes — Interpretation of electrical geophysical data in coupled stream–hyporheic zone systems during solute tracer studies     

Adam S. Ward  Michael N. Gooseff  Kamini Singha 《Advances in water resources》2010

Quantifying hyporheic solute dynamics has been limited by our ability to assess the magnitude and extent of stream interactions with multiple domains: mobile subsurface storage (MSS, e.g., freely flowing pore water) and immobile subsurface storage (ISS, e.g., poorly connected pore water). Stream-tracer experiments coupled with solute transport modeling are frequently used to characterize lumped MSS and ISS dynamics, but are limited by the ability to sample only “mobile” water and by window of detection issues. Here, we couple simulations of near-surface electrical resistivity (ER) methods with conservative solute transport to directly compare solute transport with ER interpretations, and to determine the ability of ER to predict spatial and temporal trends of solute distribution and transport in stream–hyporheic systems. Results show that temporal moments from both ER and solute transport data are well correlated for locations where advection is not the dominant solute transport process. Mean arrival time and variance are especially well-predicted by ER interpretation, providing the potential to estimate rate-limited mass transport (i.e. diffusive) parameters from these data in a distributed domain, substantially increasing our knowledge of the fate and transport of subsurface solutes.  相似文献   

Mineral matter and trace elements in coals of the Gunnedah Basin, New South Wales, Australia     

Colin R. Ward  D. A. Spears  Carol A. Booth  Ian Staton  Lila W. Gurba 《International Journal of Coal Geology》1999,40(4):2843

The concentrations of major and trace inorganic elements in a succession of Permian coals from the Gunnedah Basin, New South Wales, have been determined by X-ray fluorescence techniques applied to both whole-coal and high-temperature ash samples. The results have been evaluated in the light of quantitative data on the minerals in the same coals, determined from X-ray diffraction study of whole-coal samples using a Rietveld-based interpretation program ( ™), to determine relationships of the trace elements in the coals to the mineral species present. Comparison of the chemical composition of the coal ash interpreted from the quantitative mineralogical study to the actual ash composition determined by XRF analysis shows a high degree of consistency, confirming the validity of the XRD interpretations for the Gunnedah Basin materials. Quartz, illite and other minerals of detrital origin dominate the coals in the upper part of the sequence, whereas authigenic kaolinite is abundant in coals from the lower part of the Permian succession. These minerals are all reduced in abundance, however, and pyrite is a dominant constituent, in coals formed under marine influence at several stratigraphic levels. Calcite and dolomite occur as cleat and fracture infillings, mostly in seams near the top and bottom of the sequence. The potassium-bearing minerals in the detrital fraction are associated with significant concentrations of rubidium, and the authigenic kaolinite with relatively high proportions of titanium. Zirconium is also abundant, with associated P and Hf, in the Gunnedah Basin coal seams. Relationships exhibited by Ti, Zr, Nd and Y are consistent with derivation of the original sediment admixed with the seams from an acid volcanic source. Pyrite in the coals is associated with high concentrations of arsenic and minor proportions of thallium; no other element commonly associated with sulphides in coals, however, appears to occur in significant proportions with the pyrite in the sample suite. Small concentrations of Cl present in the coal are inversely related to the pyrite content, and appear to represent ion-exchange components associated with the organic matter. Strontium and barium are strongly associated with the cleat-filling carbonate minerals. Ge and Ga appear to be related to each other and to the coal's organic matter. Cr and V are also related to each other, as are Ce, La, Nd and Pr, but none of these show any relationship to the organic matter or a particular mineral component.  相似文献