The effect of bathymetric filtering on nearshore process model results
N.G. Plant, K.L. Edwards, J.M. Kaihatu, J. Veeramony, L. Hsu, K. T. Holland
2009, Coastal Engineering (56) 484-493
Nearshore wave and flow model results are shown to exhibit a strong sensitivity to the resolution of the input bathymetry. In this analysis, bathymetric resolution was varied by applying smoothing filters to high-resolution survey data to produce a number of bathymetric grid surfaces. We demonstrate that the sensitivity of model-predicted...
Ultrahigh resolution topographic mapping of Mars with MRO HiRISE stereo images: Meter-scale slopes of candidate Phoenix landing sites
Randolph L. Kirk, Elpitha Howington-Kraus, Mark R. Rosiek, Jeffery A. Anderson, Brent A. Archinal, Kris J. Becker, D.A. Cook, Donna M. Galuszka, Paul E. Geissler, Trent M. Hare, I.M. Holmberg, Laszlo P. Keszthelyi, Bonnie L. Redding, W.A. Delamere, D. Gallagher, J.D. Chapel, Eric M. Eliason, R. King, Alfred S. McEwen
2009, Journal of Geophysical Research E: Planets (114)
The objectives of this paper are twofold: first, to report our estimates of the meter‐to‐decameter‐scale topography and slopes of candidate landing sites for the Phoenix mission, based on analysis of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images with a typical pixel scale of 3 m and Mars Reconnaissance...
Observation and modeling of source effects in coda wave interferometry at Pavlof volcano
Matthew M. Haney, Wijik K. van, L.A. Preston, D.F. Aldridge
2009, The Leading Edge (28) 554-560
Sorting out source and path effects for seismic waves at volcanoes is critical for the proper interpretation of underlying volcanic processes. Source or path effects imply that seismic waves interact strongly with the volcanic subsurface, either through partial resonance in a conduit (Garces et al., 2000; Sturton and Neuberg, 2006)...
New light on a dark subject: On the use of fluorescence data to deduce redox states of natural organic matter (NOM)
Donald L. Macalady, Katherine Walton-Day
2009, Aquatic Sciences (71) 135-143
This paper reports the use of excitation-emission matrix fluorescence spectroscopy (EEMS), parallel factor statistical analysis (PARAFAC), and oxidation-reduction experiments to examine the effect of redox conditions on PARAFAC model results for aqueous samples rich in natural organic matter. Fifty-four aqueous samples from 11 different geographic locations and two plant extracts...
Shallow seismic structure of Kunlun fault zone in northern Tibetan Plateau, China: Implications for the 2001 M s8.1 Kunlun earthquake
Chun-Yong Wang, Walter D. Mooney, Z. Ding, J. Yang, Z. Yao, H. Lou
2009, Geophysical Journal International (177) 978-1000
The shallow seismic velocity structure of the Kunlun fault zone (KLFZ) was jointly deduced from seismic refraction profiling and the records of trapped waves that were excited by five explosions. The data were collected after the 2001 Kunlun Ms8.1 earthquake in the northern Tibetan Plateau. Seismic phases for the in-line record...
Unique problems associated with seismic analysis of partially gas-saturated unconsolidated sediments
Myung W. Lee, T. S. Collett
2009, Marine and Petroleum Geology (26) 775-781
Gas hydrate stability conditions restrict the occurrence of gas hydrate to unconsolidated and high water-content sediments at shallow depths. Because of these host sediments properties, seismic and well log data acquired for the detection of free gas and associated gas hydrate-bearing sediments often require nonconventional analysis. For example, a conventional...
Assessment of planetary geologic mapping techniques for Mars using terrestrial analogs: The SP Mountain area of the San Francisco Volcanic Field, Arizona
Kenneth L. Tanaka, James A. Skinner, Larry S. Crumpler, James M. Dohm
2009, Planetary and Space Science (57) 510-532
We photogeologically mapped the SP Mountain region of the San Francisco Volcanic Field in northern Arizona, USA to evaluate and improve the fidelity of approaches used in geologic mapping of Mars. This test site, which was previously mapped in the field, is chiefly composed of Late Cenozoic cinder cones, lava...
Using nitrate to quantify quick flow in a karst aquifer
B.J. Mahler, B.D. Garner
2009, Ground Water (47) 350-360
In karst aquifers, contaminated recharge can degrade spring water quality, but quantifying the rapid recharge (quick flow) component of spring flow is challenging because of its temporal variability. Here, we investigate the use of nitrate in a two-endmember mixing model to quantify quick flow in Barton Springs, Austin, Texas. Historical...
Climatic effects of 30 years of landscape change over the Greater Phoenix, Arizona, region: 1. Surface energy budget changes
M. Georgescu, G. Miguez-Macho, L. T. Steyaert, C.P. Weaver
2009, Journal of Geophysical Research D: Atmospheres (114)
This paper is part 1 of a two-part study that evaluates the climatic effects of recent landscape change for one of the nation's most rapidly expanding metropolitan complexes, the Greater Phoenix, Arizona, region. The region's landscape evolution over an approximate 30-year period since the early 1970s is documented on the...
The role of reaction affinity and secondary minerals in regulating chemical weathering rates at the Santa Cruz Soil Chronosequence, California
K. Maher, Carl Steefel, A. F. White, David A. Stonestrom
2009, Geochimica et Cosmochimica Acta (73) 2804-2831
In order to explore the reasons for the apparent discrepancy between laboratory and field weathering rates and to determine the extent to which weathering rates are controlled by the approach to thermodynamic equilibrium, secondary mineral precipitation, and flow rates, a multicomponent reactive transport model (CrunchFlow) was used to interpret soil...
Ultra-deep oxidation and exotic copper formation at the late pliocene boyongan and bayugo porphyry copper-gold deposits, surigao, philippines: Geology, mineralogy, paleoaltimetry, and their implications for Geologic, physiographic, and tectonic controls
D.P. Braxton, D. R. Cooke, A.M. Ignacio, R. O. Rye, P.J. Waters
2009, Economic Geology (104) 333-349
The Boyongan and Bayugo porphyry copper-gold deposits are part of an emerging belt of intrusion-centered gold-rich deposits in the Surigao district of northeast Mindanao, Philippines. Exhumation and weathering of these Late Pliocene-age deposits has led to the development of the world's deepest known porphyry oxidation profile at Boyongan (600 m),...
Numerical simulation of dune-flat bed transition and stage‐discharge relationship with hysteresis effect
Yasuyuki Shimizu, Sanjay Giri, Satomi Yamaguchi, Jonathan M. Nelson
2009, Water Resources Research (45)
This work presents recent advances on morphodynamic modeling of bed forms under unsteady discharge. This paper includes further development of a morphodynamic model proposed earlier by Giri and Shimizu (2006a). This model reproduces the temporal development of river dunes and accurately replicates the physical properties associated with bed form evolution....
Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake
R. O. Hall Jr., J. L. Tank, D. J. Sobota, P. J. Mulholland, J. M. O’Brien, W. K. Dodds, J.R. Webster, H. M. Valett, G. C. Poole, B. J. Peterson, J.L. Meyer, W. H. McDowell, S. L. Johnson, S. K. Hamilton, N. B. Grimm, S.V. Gregory, Clifford N. Dahm, L. W. Cooper, L. R. Ashkenas, S. M. Thomas, R.W. Sheibley, J. D. Potter, B.R. Niederlehner, L. T. Johnson, A. M. Helton, C.M. Crenshaw, A. J. Burgin, M. J. Bernot, J. J. Beaulieu, C.P. Arangob
2009, Limnology and Oceanography (54) 653-665
We measured uptake length of 15NO-3 in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO-3 uptake length. As part of the Lotic Intersite Nitrogen eXperiment II project, we chose nine streams in each region corresponding to natural...
Impacts of episodic acidification on in-stream survival and physiological impairment of Atlantic salmon (Salmo salar) smolts
S. D. McCormick, A. Keyes, K.H. Nislow, M.Y. Monette
2009, Canadian Journal of Fisheries and Aquatic Sciences (66) 394-403
We conducted field studies to determine the levels of acid and aluminum (Al) that affect survival, smolt development, ion homeostasis, and stress in Atlantic salmon (Salmo salar) smolts in restoration streams of the Connecticut River in southern Vermont, USA. Fish were held in cages in five streams encompassing a wide...
Recent experimental data may point to a greater role for osmotic pressures in the subsurface
C. E. Neuzil, A.M. Provost
2009, Water Resources Research (45)
Uncertainty about the origin of anomalous fluid pressures in certain geologic settings has caused researchers to take a second look at osmosis, or flow driven by chemical potential differences, as a pressure‐generating process in the subsurface. Interest in geological osmosis has also increased because of an in situ experiment by...
Estimating the encounter rate variance in distance sampling
R.M. Fewster, S.T. Buckland, K.P. Burnham, D.L. Borchers, P.E. Jupp, J.L. Laake, L. Thomas
2009, Biometrics (65) 225-236
The dominant source of variance in line transect sampling is usually the encounter rate variance. Systematic survey designs are often used to reduce the true variability among different realizations of the design, but estimating the variance is difficult and estimators typically approximate the variance by treating the design as a...
Methane sources in gas hydrate-bearing cold seeps: Evidence from radiocarbon and stable isotopes
J. W. Pohlman, J.E. Bauer, E. A. Canuel, K.S. Grabowski, D.L. Knies, C.S. Mitchell, Michael J. Whiticar, R.B. Coffin
2009, Marine Chemistry (115) 102-109
Fossil methane from the large and dynamic marine gas hydrate reservoir has the potential to influence oceanic and atmospheric carbon pools. However, natural radiocarbon (14C) measurements of gas hydrate methane have been extremely limited, and their use as a source and process indicator has not yet been systematically established. In...
Historical and modern disturbance regimes, stand structures, and landscape dynamics in piñon-juniper vegetation of the western United States
William H. Romme, Craig D. Allen, John D. Bailey, William L. Baker, Brandon T. Bestelmeyer, Peter M. Brown, Karen S. Eisenhart, M. Lisa Floyd, David W. Huffman, Brian F. Jacobs, Richard F. Miller, Esteban H. Muldavin, Thomas W. Swetnam, Robin J. Tausch, Peter J. Weisberg
2009, Rangeland Ecology and Management (62) 203-222
Piñon–juniper is a major vegetation type in western North America. Effective management of these ecosystems has been hindered by inadequate understanding of 1) the variability in ecosystem structure and ecological processes that exists among the diverse combinations of piñons, junipers, and associated shrubs, herbs, and soil organisms; 2) the prehistoric...
Thorium abundances on the Aristarchus plateau: Insights into the composition of the Aristarchus pyroclastic glass deposits
Justin Hagerty, D. J. Lawrence, B. R. Hawke, Lisa R. Gaddis
2009, Journal of Geophysical Research E: Planets (114)
Thorium (Th) data from the Lunar Prospector gamma ray spectrometer (LP‐GRS) are used to constrain the composition of lunar pyroclastic glass deposits on top of the Aristarchus plateau. Our goal is to use forward modeling of LP‐GRS Th data to measure the Th abundances on the plateau and then to...
Use of predictive models and rapid methods to nowcast bacteria levels at coastal beaches
Donna S. Francy
2009, Aquatic Ecosystem Health & Management (12) 177-182
The need for rapid assessments of recreational water quality to better protect public health is well accepted throughout the research and regulatory communities. Rapid analytical methods, such as quantitative polymerase chain reaction (qPCR) and immunomagnetic separation/adenosine triphosphate (ATP) analysis, are being tested but are not yet ready for widespread use.Another...
Projected climate-induced faunal change in the Western Hemisphere
J.J. Lawler, S.L. Shafer, D. White, P. Kareiva, E.P. Maurer, A.R. Blaustein, P. J. Bartlein
2009, Ecology (90) 588-597
Climate change is predicted to be one of the greatest drivers of ecological change in the coming century. Increases in temperature over the last century have clearly been linked to shifts in species distributions. Given the magnitude of projected future climatic changes, we can expect even larger range shifts in...
Simulating hydrologic and hydraulic processes throughout the Amazon River Basin
R.E. Beighley, K.G. Eggert, T. Dunne, Y. He, V. Gummadi, K.L. Verdin
2009, Hydrological Processes (23) 1221-1235
Presented here is a model framework based on a land surface topography that can be represented with various degrees of resolution and capable of providing representative channel/floodplain hydraulic characteristics on a daily to hourly scale. The framework integrates two models: (1) a water balance model (WBM) for the vertical fluxes...
Analytical modeling of gravity changes and crustal deformation at volcanoes: The Long Valley caldera, California, case study
Maurizio Battaglia, D.P. Hill
2009, Tectonophysics (471) 45-57
Joint measurements of ground deformation and micro-gravity changes are an indispensable component for any volcano monitoring strategy. A number of analytical mathematical models are available in the literature that can be used to fit geodetic data and infer source location, depth and density. Bootstrap statistical methods allow estimations of the...
Body size and predatory performance in wolves: Is bigger better?
D.R. MacNulty, D.W. Smith, L.D. Mech, L.E. Eberly
2009, Journal of Animal Ecology (78) 532-539
Large body size hinders locomotor performance in ways that may lead to trade-offs in predator foraging ability that limit the net predatory benefit of larger size. For example, size-related improvements in handling prey may come at the expense of pursuing prey and thus negate any enhancement in overall predatory performance...
Models of pure CO2 and pure CH4 adsorption on the late paleozoic coals from the Kailuan Coalfield, Hebei, China
S. Dai, B. Zhang, S. Peng, X. Zhang, C. Chou
2009, Acta Geologica Sinica (83) 731-737
Isothermal adsorption experiments of pure CO2 and CH4 on different coals in rank (the No. 11 Coal from the Linnancang Mine and the No. 9 Coal from the Majiagou Mine) from the Kailuan Coalfield of Hebei Province, China, have been studied. Four different models (Langmuir, BET, D-R, and D-A) were...
