Hydrostratigraphic analysis of the MADE site with full-resolution GPR and direct-push hydraulic profiling
M. Dogan, R. L. Van Dam, Geoffrey C. Bohling, J.J. Butler Jr., D.W. Hyndman
2011, Geophysical Research Letters (38)
Full‐resolution 3D Ground‐Penetrating Radar (GPR) data were combined with high‐resolution hydraulic conductivity (K) data from vertical Direct‐Push (DP) profiles to characterize a portion of the highly heterogeneous MAcro Dispersion Experiment (MADE) site. This is an important first step to better understand the influence of aquifer heterogeneities on observed anomalous...
Allelopathic cover crop prior to seeding is more important than subsequent grazing/mowing in Grassland establishment
D.G. Milchunas, Mark W. Vandever, L.O. Ball, S. Hyberg
2011, Rangeland Ecology and Management (64) 291-300
The effects of grazing, mowing, and type of cover crop were evaluated in a previous winter wheat–fallow cropland seeded to grassland under the Conservation Reserve Program in eastern Colorado. Prior to seeding, the fallow strips were planted to forage sorghum or wheat in alternating strips (cover crops), with no grazing, moderate to...
Sensitivity of leaf size and shape to climate: Global patterns and paleoclimatic applications
D.J. Peppe, D.L. Royer, B. Cariglino, S.Y. Oliver, S. Newman, E. Leight, G. Enikolopov, M. Fernandez-Burgos, F. Herrera, J.M. Adams, E. Correa, E.D. Currano, J.M. Erickson, L.F. Hinojosa, J.W. Hoganson, A. Iglesias, C.A. Jaramillo, K.R. Johnson, G.J. Jordan, N.J.B. Kraft, E.C. Lovelock, C.H. Lusk, U. Niinemets, J. Penuelas, G. Rapson, S.L. Wing, I.J. Wright
2011, New Phytologist (190) 724-739
Paleobotanists have long used models based on leaf size and shape to reconstruct paleoclimate. However, most models incorporate a single variable or use traits that are not physiologically or functionally linked to climate, limiting their predictive power. Further, they often underestimate paleotemperature relative to other proxies.Here we quantify leaf–climate correlations...
2-D inner-shelf current observations from a single VHF WEllen RAdar (WERA) station
G. Voulgaris, N. Kumar, K.-W. Gurgel, John C. Warner, Jeffrey H. List
2011, Conference Paper, 2011 IEEE/OES/CWTM 10th working conference on current, waves and turbulence measurement, CWTM 2011
The majority of High Frequency (HF) radars used worldwide operate at medium to high frequencies (8 to 30 MHz) providing spatial resolutions ranging from 3 to 1.5 km and ranges from 150 to 50 km. This paper presents results from the deployment of a single Very High Frequency (VHF, 48...
Testing earthquake source inversion methodologies
M. Page, P.M. Mai, D. Schorlemmer
2011, Eos, Transactions, American Geophysical Union (92) 75-75
Source Inversion Validation Workshop; Palm Springs, California, 11-12 September 2010; Nowadays earthquake source inversions are routinely performed after large earthquakes and represent a key connection between recorded seismic and geodetic data and the complex rupture process at depth. The resulting earthquake source models quantify the spatiotemporal evolution of ruptures. They...
Comparative phylogeography of a coevolved community: Concerted population expansions in Joshua trees and four Yucca moths
C.I. Smith, S. Tank, W. Godsoe, J. Levenick, Espen Strand, T. Esque, O. Pellmyr
2011, PLoS ONE (6)
Comparative phylogeographic studies have had mixed success in identifying common phylogeographic patterns among co-distributed organisms. Whereas some have found broadly similar patterns across a diverse array of taxa, others have found that the histories of different species are more idiosyncratic than congruent. The variation in the results of comparative phylogeographic...
Feasibility of waveform inversion of Rayleigh waves for shallow shear-wave velocity using a genetic algorithm
C. Zeng, J. Xia, R. D. Miller, G.P. Tsoflias
2011, Journal of Applied Geophysics (75) 648-655
Conventional surface wave inversion for shallow shear (S)-wave velocity relies on the generation of dispersion curves of Rayleigh waves. This constrains the method to only laterally homogeneous (or very smooth laterally heterogeneous) earth models. Waveform inversion directly fits waveforms on seismograms, hence, does not have such a limitation. Waveforms of...
The efficacy of salvage logging in reducing subsequent fire severity in conifer-dominated forests of Minnesota, USA
S. Fraver, T. Jain, J.B. Bradford, A.W. D’Amato, D. Kastendick, B. Palik, D. Shinneman, J. Stanovick
2011, Ecological Applications (21) 1895-1901
Although primarily used to mitigate economic losses following disturbance, salvage logging has also been justified on the basis of reducing fire risk and fire severity; however, its ability to achieve these secondary objectives remains unclear. The patchiness resulting from a sequence of recent disturbances—blowdown, salvage logging, and wildfire—provided an excellent...
Metallothionein-like multinuclear clusters of mercury(II) and sulfur in peat
K. L. Nagy, A. Manceau, J. D. Gasper, J. N. Ryan, G. R. Aiken
2011, Environmental Science & Technology (45) 7298-7306
Strong mercury(II)–sulfur (Hg-SR) bonds in natural organic matter, which influence mercury bioavailability, are difficult to characterize. We report evidence for two new Hg-SR structures using X-ray absorption spectroscopy in peats from the Florida Everglades with added Hg. The first, observed at...
Marine and terrestrial factors affecting Adélie penguin Pygoscelis adeliae chick growth and recruitment off the western Antarctic Peninsula
Erik W. Chapman, Eileen E. Hofmann, Donna L. Patterson, Christine A. Ribic, William R. Fraser
2011, Marine Ecology Progress Series (436) 273-289
An individual-based bioenergetics model that simulates the growth of an Adélie penguin Pygoscelis adeliaechick from hatching to fledging was used to assess marine and terrestrial factors that affect chick growth and fledging mass off the western Antarctic Peninsula. Simulations considered the effects on Adélie penguin fledging mass of (1) modification of...
Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States
Richard A. Rebich, Natalie A. Houston, Scott V. Mize, Daniel Pearson, Patricia B. Ging, Hornig C. Evan
2011, Journal of the American Water Resources Association (47) 1061-1086
SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South‐Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas‐White‐Red, and Texas‐Gulf hydrologic...
A natural experiment on the condition-dependence of achromatic plumage reflectance in black-capped chickadees
L. D'Alba, Caroline R. Van Hemert, Colleen M. Handel, M.D. Shawkey
2011, PLoS ONE (6)
Honest advertisement models posit that only individuals in good health can produce and/or maintain ornamental traits. Even though disease has profound effects on condition, few studies have experimentally tested its effects on trait expression and even fewer have identified a mechanistic basis for these effects. Recent evidence suggests that black...
On the Hydrologic Adjustment of Climate-Model Projections: The Potential Pitfall of Potential Evapotranspiration
Paul C.D. Milly, Krista A. Dunne
2011, Earth Interactions (15) 1-14
Hydrologic models often are applied to adjust projections of hydroclimatic change that come from climate models. Such adjustment includes climate-bias correction, spatial refinement ("downscaling"), and consideration of the roles of hydrologic processes that were neglected in the climate model. Described herein is a quantitative analysis of the effects of hydrologic...
A probabilistic seismic risk assessment procedure for nuclear power plants: (I) Methodology
Y.-N. Huang, A.S. Whittaker, N. Luco
2011, Nuclear Engineering and Design (241) 3996-4003
A new procedure for probabilistic seismic risk assessment of nuclear power plants (NPPs) is proposed. This procedure modifies the current procedures using tools developed recently for performance-based earthquake engineering of buildings. The proposed procedure uses (a) response-based fragility curves to represent the capacity of structural and nonstructural components of NPPs,...
Late-Holocene climate evolution at the WAIS Divide site, West Antarctica: Bubble number-density estimates
John M. Fegyveresi, R. B. Alley, M. K. Spencer, J. J. Fitzpatrick, E.J. Steig, J.W.C. White, J.R. McConnell, K.C. Taylor
2011, Journal of Glaciology (57) 629-638
A surface cooling of ∼1.7°C occurred over the ∼two millennia prior to ∼1700 CE at the West Antarctic ice sheet (WAIS) Divide site, based on trends in observed bubble number-density of samples from the WDC06A ice core, and on an independently constructed accumulation-rate history using annual-layer dating corrected for density...
The Regionalization of National-Scale SPARROW Models for Stream Nutrients
Gregory E. Schwarz, Richard B. Alexander, Richard A. Smith, Stephen D. Preston
2011, Journal of the American Water Resources Association (47) 1151-1172
This analysis modifies the parsimonious specification of recently published total nitrogen (TN) and total phosphorus (TP) national‐scale SPAtially Referenced Regressions On Watershed attributes models to allow each model coefficient to vary geographically among three major river basins of the conterminous United States. Regionalization of the national models reduces the standard...
Estimating water supply arsenic levels in the New England bladder cancer study
J.R. Nuckols, Freeman L.E. Beane, J.H. Lubin, M.S. Airola, D. Baris, J. D. Ayotte, A. Taylor, C. Paulu, M.R. Karagas, J. Colt, M.H. Ward, A.-T. Huang, W. Bress, S. Cherala, D.T. Silverman, K.P. Cantor
2011, Environmental Health Perspectives (119) 1279-1285
Background: Ingestion of inorganic arsenic in drinking water is recognized as a cause of bladder cancer when levels are relatively high (≥ 150 µg/L). The epidemiologic evidence is less clear at the low-to-moderate concentrations typically observed in the United States. Accurate retrospective exposure assessment over a long time period is...
East Antarctic rifting triggers uplift of the Gamburtsev Mountains
Fausto Ferraccioli, Carol A. Finn, Tom A. Jordan, Robin E. Bell, Lester M. Anderson, Detlef Damaske
2011, Nature (479) 388-392
The Gamburtsev Subglacial Mountains are the least understood tectonic feature on Earth, because they are completely hidden beneath the East Antarctic Ice Sheet. Their high elevation and youthful Alpine topography, combined with their location on the East Antarctic craton, creates a paradox that has puzzled researchers since the mountains were...
High-frequency Born synthetic seismograms based on coupled normal modes
F. Pollitz
2011, Geophysical Journal International (187) 1420-1442
High-frequency and full waveform synthetic seismograms on a 3-D laterally heterogeneous earth model are simulated using the theory of coupled normal modes. The set of coupled integral equations that describe the 3-D response are simplified into a set of uncoupled integral equations by using the Born approximation to calculate scattered...
Quantifying the hydrological responses to climate change in an intact forested small watershed in Southern China
G. Zhou, X. Wei, Y. Wu, Y. Huang, J. Yan, Dongxiao Zhang, Q. Zhang, J. Liu, Z. Meng, C. Wang, G. Chu, S. Liu, X. Tang, Xiuying Liu
2011, Global Change Biology (17) 3736-3746
Responses of hydrological processes to climate change are key components in the Intergovernmental Panel for Climate Change (IPCC) assessment. Understanding these responses is critical for developing appropriate mitigation and adaptation strategies for sustainable water resources management and protection of public safety. However, these responses are not well understood and little...
Integration of Palmer Drought Severity Index and remote sensing data to simulate wetland water surface from 1910 to 2009 in Cottonwood Lake area, North Dakota
Shengli Huang, Devendra Dahal, Claudia Young, Gyanesh Chander, Shuguang Liu
2011, Remote Sensing of Environment (115) 3377-3389
Spatiotemporal variations of wetland water in the Prairie Pothole Region are controlled by many factors; two of them are temperature and precipitation that form the basis of the Palmer Drought Severity Index (PDSI). Taking the 196 km2 Cottonwood Lake area in North Dakota as our pilot study site, we integrated PDSI, Landsat...
Titan's cloud seasonal activity from winter to spring with Cassini/VIMS
S. Rodriguez, S. Le Mouelic, P. Rannou, Christophe Sotin, R. H. Brown, J. W. Barnes, C.A. Griffith, J. Burgalat, K. H. Baines, B. J. Buratti, R. N. Clark, P. D. Nicholson
2011, Icarus (216) 89-110
Since Saturn orbital insertion in July 2004, the Cassini orbiter has been observing Titan throughout most of the northern winter season (October 2002–August 2009) and the beginning of spring, allowing a detailed monitoring of Titan’s cloud coverage at high spatial resolution with close flybys on a monthly basis. This...
A working environment for digital planetary data processing and mapping using ISIS and GRASS GIS
A. Frigeri, T. Hare, M. Neteler, A. Coradini, C. Federico, R. Orosei
2011, Conference Paper, Planetary and Space Science
Since the beginning of planetary exploration, mapping has been fundamental to summarize observations returned by scientific missions. Sensor-based mapping has been used to highlight specific features from the planetary surfaces by means of processing. Interpretative mapping makes use of instrumental observations to produce thematic maps that summarize observations of actual...
Surface-water nutrient conditions and sources in the United States Pacific Northwest
D.R. Wise, H.M. Johnson
2011, Journal of the American Water Resources Association (47) 1110-1135
The SPAtially Referenced Regressions On Watershed attributes (SPARROW) model was used to perform an assessment of surface-water nutrient conditions and to identify important nutrient sources in watersheds of the Pacific Northwest region of the United States (U.S.) for the year 2002. Our models included variables representing nutrient sources as well...
Homogenization of large-scale movement models in ecology
M.J. Garlick, J. A. Powell, M.B. Hooten, L.R. McFarlane
2011, Bulletin of Mathematical Biology (73) 2088-2108
A difficulty in using diffusion models to predict large scale animal population dispersal is that individuals move differently based on local information (as opposed to gradients) in differing habitat types. This can be accommodated by using ecological diffusion. However, real environments are often spatially complex, limiting application of a direct...
