Conference Papers
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The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
Browse almost 5,000 conference papers authored by our scientists and refine search by topic, location, year, and advanced search.
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State-parameter estimation of ecosystem models using a smoothed ensemble Kalman filter State-parameter estimation of ecosystem models using a smoothed ensemble Kalman filter
Much of the effort in data assimilation methods for carbon dynamics analysis has focused on estimating optimal values for either model parameters or state variables. The main weakness of estimating parameter values alone (i.e., without considering state variables) is that all errors from input, output, and model structure are attributed to model parameter uncertainties. On the other hand...
Authors
M. Chen, Shuguang Liu, Larry L. Tieszen
Uncertainty management, spatial and temporal reasoning, and validation of intelligent environmental decision support systems Uncertainty management, spatial and temporal reasoning, and validation of intelligent environmental decision support systems
There are inherent open problems arising when developing and running Intelligent Environmental Decision Support Systems (IEDSS). During daily operation of IEDSS several open challenge problems appear. The uncertainty of data being processed is intrinsic to the environmental system, which is being monitored by several on-line sensors and off-line data. Thus, anomalous data values at data
Authors
Miquel Sanchez-Marre, Karina Gilbert, Rick S. Sojda, Jean Philippe Steyer, Peter Struss, Ignasi Rodriguez-Roda
Upscaling terrestrial carbon dynamics from sites to regions with uncertainty measures—The GEMS experience Upscaling terrestrial carbon dynamics from sites to regions with uncertainty measures—The GEMS experience
No abstract available.
Authors
Shuguang Liu, Z. Li, Jinxun Liu, Thomas Loveland, M. Chen, Larry L. Tieszen
Resolving model parameter values from C and N stock measurements in a wide range of tropical mature forests using nonlinear inversion Resolving model parameter values from C and N stock measurements in a wide range of tropical mature forests using nonlinear inversion
No abstract available.
Authors
Shuguang Liu, Pamela Anderson, Guoyi Zhou, Boone Kauffman, Flint Hughes, David Schimel, Vicente Watson, Joseph Tosi
Dealing with uncertainty and sensitivity issues in process-based models of carbon and nitrogen cycles in northern forest ecosystems Dealing with uncertainty and sensitivity issues in process-based models of carbon and nitrogen cycles in northern forest ecosystems
Many process-based models on carbon (C) and nitrogen (N) cycles have been developed for northern forest ecosystems. These models are widely used to evaluate the long-term decisions in forest management dealing with effects like particulate pollution, productivity and climate change. Regarding climate change, one of the key questions that have sensitive political implications is whether...
Authors
Guy R. Larocque, Jagtar S. Bhatti, A.M. Gordon, N. Luckai, Jinxun Liu, Shuguang Liu, P.A. Arp, C.F. Zhang, A Komarov, P. Grabarnik, M. Wattenbach, C. Peng, Jianfeng Sun, Thomas White
A tool for assessing mercury loadings from restored tidal systems A tool for assessing mercury loadings from restored tidal systems
Accurately quantifying net loads in tidal systems is difficult owing to the high variability in constituent concentrations over the vastly different time scales present in these systems. Perhaps most difficult is the measurement of fluxed over the tidal time scale. On this scale, the net export of the constituent is orders of magnitude less than the bulk exchange in either direction...
Authors
J.A. Fleck, B.A. Bergamaschi, B.D. Downing, M. A. Lionberger, D. H. Schoellhamer, E. Boss, M. Stephenson
Sediment supply and demand for salt pond restoration Sediment supply and demand for salt pond restoration
No abstract available.
Authors
David H. Schoellhamer, James L. Orlando, Scott Wright, Larry A. Freeman
Applications of geophysical methods to volcano monitoring Applications of geophysical methods to volcano monitoring
The array of geophysical technologies used in volcano hazards studies - some developed originally only for volcano monitoring - ranges from satellite remote sensing including InSAR to leveling and EDM surveys, campaign and telemetered GPS networks, electronic tiltmeters and strainmeters, airborne magnetic and electromagnetic surveys, short-period and broadband seismic monitoring, even...
Authors
Jeff Wynn, Daniel Dzurisin, Carol A. Finn, James P. Kauahikaua, Richard G. Lahusen
Magnetic properties, acid neutralization capacity, and net acid production of rocks in the Animas River Watershed Silverton, Colorado Magnetic properties, acid neutralization capacity, and net acid production of rocks in the Animas River Watershed Silverton, Colorado
Federal land managers along with local stakeholders in the Upper Animas River watershed near Silverton, Colorado are actively designing and implementing mine waste remediation projects to mitigate the effects of acid mine drainage from several abandoned hard rock metal mines and mills. Local source rocks with high acid neutralization capacity (ANC) within the watershed are of interest to...
Authors
Anne E. McCafferty, Douglas B. Yager, Radley M. Horton, Sharon F. Diehl
Lessons learned from the U.S. Geological Survey abandoned mine lands initiative: 1997-2002 Lessons learned from the U.S. Geological Survey abandoned mine lands initiative: 1997-2002
Growth of the United States has been facilitated, in part, by hard-rock mining in the Rocky Mountains. Abandoned and inactive mines cause many significant environmental concerns in hundreds of watersheds. Those who have responsibility to address these environmental concerns must have a basic level of scientific information about mining and mine wastes in a watershed prior to initiating...
Authors
Briant A. Kimball, Stan E. Church, John M. Besser
What's weathering? Mineralogy and field leach studies in mine waste, Leadville and Montezuma mining districts, Colorado What's weathering? Mineralogy and field leach studies in mine waste, Leadville and Montezuma mining districts, Colorado
Weathering is important in the development of rock fabrics that control porosity in mine-waste materials, and in turn, porosity affects metal transport through and from mine-waste piles into watersheds. Mine-waste piles are dynamic physical and chemical systems as evidenced by remnant Fe-oxide boxwork structures after sulfide minerals, development of alteration rinds and etch pits on...
Authors
S. F. Diehl, Phil L. Hageman, Kathleen S. Smith
Predicting toxic effects of copper on aquatic biota in mineralized areas by using the Biotic Ligand Model Predicting toxic effects of copper on aquatic biota in mineralized areas by using the Biotic Ligand Model
The chemical speciation of metals influences their biological effects. The Biotic Ligand Model (BLM) is a computational approach to predict chemical speciation and acute toxicological effects of metals on aquatic biota. Recently, the U.S. Environmental Protection Agency incorporated the BLM into their regulatory water-quality criteria for copper. Results from three different laboratory...
Authors
Kathleen S. Smith, James F. Ranville, M. Adams, LaDonna M. Choate, Stan E. Church, David L. Fey, Richard B. Wanty, James G. Crock