Identification, prediction, and mitigation of sinkhole hazards in evaporite karst areas
F. Gutierrez, A.H. Cooper, K.S. Johnson
2008, Conference Paper, Environmental Geology
Sinkholes usually have a higher probability of occurrence and a greater genetic diversity in evaporite terrains than in carbonate karst areas. This is because evaporites have a higher solubility and, commonly, a lower mechanical strength. Subsidence damage resulting from evaporite dissolution generates substantial losses throughout the world, but the causes...
Secrets in the eyes of Black Oystercatchers: A new sexing technique
Brian M. Guzzetti, Sandra L. Talbot, David F. Tessler, Verena A. Gill, Edward C. Murphy
2008, Journal of Field Ornithology (79) 215-223
Sexing oystercatchers in the field is difficult because males and females have identical plumage and are similar in size. Although Black Oystercatchers (Haematopus bachmani) are sexually dimorphic, using morphology to determine sex requires either capturing both pair members for comparison or using discriminant analyses to assign sex probabilistically based on...
Mangrove forest distributions and dynamics in Madagascar (1975-2005)
S. Giri, J. Muhlhausen
2008, Sensors (8) 2104-2117
Mangrove forests of Madagascar are declining, albeit at a much slower rate than the global average. The forests are declining due to conversion to other land uses and forest degradation. However, accurate and reliable information on their present distribution and their rates, causes, and consequences of change have not been...
Aseismic slip and fault-normal strain along the central creeping section of the San Andreas fault
F. Rolandone, R. Burgmann, D.C. Agnew, I.A. Johanson, D.C. Templeton, M. A. d'Alessio, S.J. Titus, C. DeMets, B. Tikoff
2008, Geophysical Research Letters (35)
We use GPS data to measure the aseismic slip along the central San Andreas fault (CSAF) and the deformation across adjacent faults. Comparison of EDM and GPS data sets implies that, except for small-scale transients, the fault motion has been steady over the last 40 years. We add 42 new...
Biological assessments of Appalachian streams based on predictive models for fish, macroinvertebrate, and diatom assemblages
D.M. Carlisle, C.P. Hawkins, M. R. Meador, M. Potapova, J. Falcone
2008, Journal of the North American Benthological Society (27) 16-37
We developed empirical models for fish, macroinvertebrate, and diatom assemblages to assess the biological condition of 268 streams sampled from 1993 to 2002 in 7 major river basins in the Appalachian region of the USA. These models estimate the expected taxonomic composition at each site based on observed variation in...
Using the Model Coupling Toolkit to couple earth system models
J.C. Warner, N. Perlin, E.D. Skyllingstad
2008, Environmental Modelling and Software (23) 1240-1249
Continued advances in computational resources are providing the opportunity to operate more sophisticated numerical models. Additionally, there is an increasing demand for multidisciplinary studies that include interactions between different physical processes. Therefore there is a strong desire to develop coupled modeling systems that utilize existing models and allow efficient data...
Modelling the impact of wind stress and river discharge on Danshuei River plume
W.-C. Liu, W.-B. Chen, R. T. Cheng, M.-H. Hsu
2008, Applied Mathematical Modelling (32) 1255-1280
A three-dimensional, time-dependent, baroclinic, hydrodynamic and salinity model, UnTRIM, was performed and applied to the Danshuei River estuarine system and adjacent coastal sea in northern Taiwan. The model forcing functions consist of tidal elevations along the open boundaries and freshwater inflows from the main stream and major tributaries in the...
Distribution of icy particles across Enceladus' surface as derived from Cassini-VIMS measurements
R. Jaumann, K. Stephan, G. B. Hansen, R. N. Clark, B. J. Buratti, R. H. Brown, K. H. Baines, S.F. Newman, G. Bellucci, G. Filacchione, A. Coradini, D. P. Cruikshank, C.A. Griffith, C. A. Hibbitts, T. B. McCord, R.M. Nelson, P. D. Nicholson, Christophe Sotin, R. Wagner
2008, Icarus (193) 407-419
The surface of Enceladus consists almost completely of water ice. As the band depths of water ice absorptions are sensitive to the size of particles, absorptions can be used to map variations of icy particles across the surface. The Visual and Infrared Mapping Spectrometer (VIMS) observed Enceladus with a high...
Anatomy and dynamics of a floodplain, Powder River, Montana, U.S.A.
J.E. Pizzuto, J. A. Moody, R.H. Meade
2008, Journal of Sedimentary Research (78) 16-28
Centimeter-scale measurements on several Powder River floodplains provide insights into the nature of overbank depositional processes that created the floodplains; during a 20-year period after a major flood in 1978. Rising stages initially entered across a sill at the downriver end of the floodplains. Later, as stages continued to rise,...
Observations and interpretation of fundamental mode Rayleigh wavefields recorded by the Transportable Array (USArray)
F. F. Pollitz
2008, Journal of Geophysical Research B: Solid Earth (113)
Broadband recordings of the dense Transportable Array (TA) in the western United States provide unparalleled detailed images of long-period seismic surface wavefields. With 400 stations spanning most of the western United States, wavefronts of fundamental mode Rayleigh waves may be visualized coherently across the array at periods ???40 s. In...
The Landsat Image Mosaic of Antarctica
Robert Bindschadler, P. Vornberger, A. Fleming, A. Fox, J. Mullins, D. Binnie, S.J. Paulsen, Brian J. Granneman, D. Gorodetzky
2008, Remote Sensing of Environment (112) 4214-4226
The Landsat Image Mosaic of Antarctica (LIMA) is the first true-color, high-spatial-resolution image of the seventh continent. It is constructed from nearly 1100 individually selected Landsat-7 ETM+ scenes. Each image was orthorectified and adjusted for geometric, sensor and illumination variations to a standardized, almost seamless surface reflectance product. Mosaicing to...
Modeling multi-layer effects in passive microwave remote sensing of dry snow using Dense Media Radiative Transfer Theory (DMRT) based on quasicrystalline approximation
D. Liang, X. Xu, L. Tsang, K.M. Andreadis, E.G. Josberger
2008, Conference Paper, International Geoscience and Remote Sensing Symposium (IGARSS)
The Dense Media Radiative Transfer theory (DMRT) of Quasicrystalline Approximation of Mie scattering by sticky particles is used to study the multiple scattering effects in layered snow in microwave remote sensing. Results are illustrated for various snow profile characteristics. Polarization differences and frequency dependences of multilayer snow model are significantly...
An improved state-parameter analysis of ecosystem models using data assimilation
M. Chen, S. Liu, L.L. Tieszen, D.Y. Hollinger
2008, Ecological Modelling (219) 317-326
Much of the effort spent in developing 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...
Fluctuating Arctic Sea ice thickness changes estimated by an in situ learned and empirically forced neural network model
G. I. Belchansky, David C. Douglas, Nikita G. Platonov
2008, Journal of Climate (21) 716-729
Sea ice thickness (SIT) is a key parameter of scientific interest because understanding the natural spatiotemporal variability of ice thickness is critical for improving global climate models. In this paper, changes in Arctic SIT during 1982-2003 are examined using a neural network (NN) algorithm trained with in situ submarine ice...
Fundamental limits to the accuracy of deuterium isotopes for identifying the spatial origin of migratory animals
A. Farmer, B.S. Cade, J. Torres-Dowdall
2008, Oecologia (158) 183-192
Deuterium isotope analyses have revolutionized the study of migratory connectivity because global gradients of deuterium in precipitation (??DP) are expressed on a continental scale. Several authors have constructed continental scale base maps of ??DP to provide a spatial reference for studying the movement patterns of migratory species and, although they...
An assessment of the effects of cell size on AGNPS modeling of watershed runoff
S.-S. Wu, E.L. Usery, M.P. Finn, D.D. Bosch
2008, Cartography and Geographic Information Science (35) 265-278
This study investigates the changes in simulated watershed runoff from the Agricultural NonPoint Source (AGNPS) pollution model as a function of model input cell size resolution for eight different cell sizes (30 m, 60 m, 120 m, 210 m, 240 m, 480 m, 960 m, and 1920 m) for the...
Modeling mechanisms of vegetation change due to fire in a semi-arid ecosystem
J.D. White, K.J. Gutzwiller, W.C. Barrow, L.J. Randall, P. Swint
2008, Ecological Modelling (214) 181-200
Vegetation growth and community composition in semi-arid environments is determined by water availability and carbon assimilation mechanisms specific to different plant types. Disturbance also impacts vegetation productivity and composition dependent on area affected, intensity, and frequency factors. In this study, a new spatially explicit ecosystem model is presented for the...
Long-term changes in the phosphorus loading to and trophic state of the Salton Sea, California
Dale M. Robertson, S.G. Schladow, G.C. Holdren
2008, Hydrobiologia (604) 21-36
The Salton Sea (Sea) is a eutrophic to hypereutrophic lake characterized by high nutrient concentrations, low water clarity, and high biological productivity. Based on dissolved phosphorus (P) and nitrogen (N) concentrations and N:P ratios, P is typically the limiting nutrient in the Sea and, therefore, should be the primary nutrient...
Sensitivity of June near‐surface temperatures and precipitation in the eastern United States to historical land cover changes since European settlement
John E. Strack, Roger A. Pielke Sr., Louis T. Steyaert, Robert G. Knox
2008, Water Resources Research (44) 1-13
Land cover changes alter the near surface weather and climate. Changes in land surface properties such as albedo, roughness length, stomatal resistance, and leaf area index alter the surface energy balance, leading to differences in near surface temperatures. This study utilized a newly developed land cover data set for the...
Updated radiometric calibration for the Landsat-5 thematic mapper reflective bands
D. L. Helder, B. L. Markham, K. J. Thome, J. A. Barsi, G. Chander, R. Malla
2008, Conference Paper
The Landsat-5 Thematic Mapper (TM) has been the workhorse of the Landsat system. Launched in 1984, it continues collecting data through the time frame of this paper. Thus, it provides an invaluable link to the past history of the land features of the Earth's surface, and it becomes imperative to...
Using demography and movement behavior to predict range expansion of the southern sea otter.
M. T. Tinker, D.F. Doak, J. A. Estes
2008, Ecological Applications (18) 1781-1794
In addition to forecasting population growth, basic demographic data combined with movement data provide a means for predicting rates of range expansion. Quantitative models of range expansion have rarely been applied to large vertebrates, although such tools could be useful for restoration and management of many threatened but recovering populations....
Regularized joint inverse estimation of extreme rainfall amounts in ungauged coastal basins of El Salvador
M.J. Friedel
2008, Natural Hazards (46) 15-34
A regularized joint inverse procedure is presented and used to estimate the magnitude of extreme rainfall events in ungauged coastal river basins of El Salvador: Paz, Jiboa, Grande de San Miguel, and Goascoran. Since streamflow measurements reflect temporal and spatial rainfall information, peak-flow discharge is hypothesized to represent a similarity...
Efficacy of algal metrics for assessing nutrient and organic enrichment in flowing waters
S. D. Porter, D. K. Mueller, N.E. Spahr, M.D. Munn, N. M. Dubrovsky
2008, Freshwater Biology (53) 1036-1054
1. Algal-community metrics were calculated for periphyton samples collected from 976 streams and rivers by the U.S. Geological Survey’s National Water-Quality Assessment (NAWQA) Programme during 1993–2001 to evaluate national and regional relations with water chemistry and to compare whether algal-metric values differ significantly among undeveloped and developed land-use classifications. 2. Algal...
Building hierarchical models of avian distributions for the State of Georgia
J.E. Howell, J.T. Peterson, M.J. Conroy
2008, Journal of Wildlife Management (72) 168-178
To predict the distributions of breeding birds in the state of Georgia, USA, we built hierarchical models consisting of 4 levels of nested mapping units of decreasing area: 90,000 ha, 3,600 ha, 144 ha, and 5.76 ha. We used the Partners in Flight database of point counts to generate presence...
A study of methods to estimate debris flow velocity
A.B. Prochaska, P.M. Santi, J.D. Higgins, S.H. Cannon
2008, Landslides (5) 431-444
Debris flow velocities are commonly back-calculated from superelevation events which require subjective estimates of radii of curvature of bends in the debris flow channel or predicted using flow equations that require the selection of appropriate rheological models and material property inputs. This research investigated difficulties associated with the use of...
