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Articles 1 - 9 of 9
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Probing Earth Deformation In Response To Localized Hydrologic Mass Loading, Susitna River Basin, Alaska, Andrew Parker Keene
Probing Earth Deformation In Response To Localized Hydrologic Mass Loading, Susitna River Basin, Alaska, Andrew Parker Keene
Graduate Student Theses, Dissertations, & Professional Papers
Surface mass loading contributes a ubiquitous signal to GPS time series that can be modeled and removed for individual sources. We utilize nine GPS stations in the Susitna River watershed, Alaska, to investigate surface displacements from surface mass loading. We find that modeling atmospheric surface pressure and regional hydrologic mass reduces root mean square (RMS) error by 27-39% for all GPS time series. We observe moderate correlation between residual time series pairs and distance, with elevation differences influencing the strength of this correlation. Seasonal horizontal and vertical displacements are observed after removal of all loading models; stations displace downward and …
Utilization Of Various Methods And A Landsat Ndvi/Google Earth Engine Product For Classifying Irrigated Land Cover, Andrew Nemecek
Utilization Of Various Methods And A Landsat Ndvi/Google Earth Engine Product For Classifying Irrigated Land Cover, Andrew Nemecek
Graduate Student Theses, Dissertations, & Professional Papers
Methods for classifying irrigated land cover are often complex and not quickly reproducible. Further, moderate resolution time-series datasets have been consistently utilized to produce irrigated land cover products over the past decade, and the body of irrigation classification literature contains no examples of subclassification of irrigated land cover by irrigation method. Creation of geospatial irrigated land cover products with higher resolution datasets could improve reliability, and subclassification of irrigation by method could provide better information for hydrologists and climatologists attempting to model the role of irrigation in the surface-ground water cycle and the water-energy balance. This study summarizes a simple, …
Ice Flow Impacts The Firn Structure Of Greenland's Percolation Zone, Rosemary C. Leone
Ice Flow Impacts The Firn Structure Of Greenland's Percolation Zone, Rosemary C. Leone
Graduate Student Theses, Dissertations, & Professional Papers
One dimensional simulations of firn evolution neglect horizontal transport as the firn column moves down slope during burial. This approach is justifiable near Greenland's ice divide, where ice flow is near vertical, but fidelity is lost in the percolation zone where horizontal ice flow advects the firn column through climate gradients. We simulate firn evolution processes under advection conditions using a transient, thermo-mechanically coupled model for firn densification and heat transfer with various schemes for meltwater penetration and refreezing. The simulations isolate processes in synthetic runs and investigate an ice core site and four transects of Greenland’s percolation zone. The …
A Dual State Hierarchical Ensemble Kalman Filter Algorithm, William J. Cook, Jesse Johnson, Marko Maneta, Doug Brinkerhoff
A Dual State Hierarchical Ensemble Kalman Filter Algorithm, William J. Cook, Jesse Johnson, Marko Maneta, Doug Brinkerhoff
Graduate Student Theses, Dissertations, & Professional Papers
Dynamic models that simulate processes across large geographic locations, such as hydrologic models, are often informed by empirical parameters that are distributed across a geographical area and segmented by geological features such as watersheds. These parameters may be referred to as spatially distributed parameters. Spatially distributed parameters are frequently spatially correlated and any techniques utilized in their calibration ideally incorporate existing spatial hierarchical relationships into their structure. In this paper, a parameter estimation method based on the Dual State Ensemble Kalman Filter called the Dual State Hierarchical Ensemble Kalman Filter (DSHEnKF) is presented. This modified filter is innovative in that …
Influence Of Large Wood On Sediment Routing In A Mixed Bedrock-Alluvial Stream, Robin Welling
Influence Of Large Wood On Sediment Routing In A Mixed Bedrock-Alluvial Stream, Robin Welling
Graduate Student Theses, Dissertations, & Professional Papers
Sediment storage by instream wood in forested mountain streams mediates sediment movement from hillslopes through the channel network and can alter channel morphology at multiple spatial scales. Mixed bedrock-alluvial channels are prevalent in mountain stream networks, yet the distribution and geomorphic impact of large wood within these streams are poorly understood. To estimate how the distribution of large wood in a mixed bedrock-alluvial stream relates to sediment storage, we measured and characterized large wood, and surveyed the volume of associated sediment within a stream in the Bitterroot Mountains, Montana. The upstream portion of the study reach is predominantly alluvial and …
Spatiotemporal Dynamics Of Nitrogen And Carbon Biogeochemistry In A Wetland-Stream Sequence, Patrick E. Hurley
Spatiotemporal Dynamics Of Nitrogen And Carbon Biogeochemistry In A Wetland-Stream Sequence, Patrick E. Hurley
Graduate Student Theses, Dissertations, & Professional Papers
Studies of aquatic ecosystems often segregate streams from the influential ponds, lakes, and wetland zones that act as important transitions between terrestrial and fluvial systems. Across the aquatic landscape, these zones interact to form linked ecosystems that function as discrete nutrient processing domains, shifting biogeochemical signals due to spatial and temporal variability in hydrologic and biologic controls. Using a mass-balance approach, we profiled nutrient dynamics along a 23-km wetland-stream sequence over three seasons. Hydrologic, morphologic, and biologic conditions, as well as landscape attributes, were quantified to determine potential controls on biogeochemical cycling in a tributary of the Upper Clark Fork …
Colloidal And Truly Dissolved Metal(Loid)S In Wastewater Lagoons And Their Removal With Floating Treatment Wetlands, Lauren Sullivan
Colloidal And Truly Dissolved Metal(Loid)S In Wastewater Lagoons And Their Removal With Floating Treatment Wetlands, Lauren Sullivan
Graduate Student Theses, Dissertations, & Professional Papers
Climate change is predicted to cause continuing declines in late-season streamflow, thus increasing the relative contribution of wastewater effluent to surface water flows. Wastewater effluent represents a critical point source of metal and metalloid contamination to aquatic ecosystems and wastewater lagoons are the most common wastewater treatment system in the rural United States. Although the fraction of total wastewater metals and metalloids in "dissolved" forms (defined here asnm) likely drives the potential for negative effects on receiving waters, this broad operational definition lumps truly dissolved solutes (nm) with small colloids and nanomaterials (1-450 nm; hereafter colloids). This size distinction may …
A Record Of The Precambrian-Cambrian Transition In Sw Montana: A Late Neoproterozoic To Early Cambrian Stratigraphic Window, Fortunian Biostratigraphic Assemblage And Treptichnus Pedum, R. Reid Trippe
Graduate Student Theses, Dissertations, & Professional Papers
This study documents a Late Neoproterozoic through Early Cambrian stratigraphic record in the Humbolt anticline of southwestern Montana. The Precambrian-Cambrian transition includes a Fortunian-aged biostratigraphic trace-fossil assemblage with the ichnofossil Treptichnus pedum. The Humbolt anticline represents an inverted paleo-graben that exposes a stratigraphic window interpreted to be a record of rifting along the Cordilleran miogeoclinal margin, linked with the breakup of the Rodinia supercontinent. The graben subsided and captured sediment during late-stage rifting and final-stage dissociation along the rift margin. Its structural axis paralleled the rift margin. Sevier/Laramide orogenic thrusting inverted the graben into the Humbolt anticline. The Late …
Determining The Precambrian Structure And Thermotectonic Evolution Of The Central Ruby Range, Southwest Montana, Sara Vivienne Stotter
Determining The Precambrian Structure And Thermotectonic Evolution Of The Central Ruby Range, Southwest Montana, Sara Vivienne Stotter
Graduate Student Theses, Dissertations, & Professional Papers
The Ruby Range in southwestern Montana is a fundamental location within the Archean Wyoming craton for examining Precambrian crustal architecture and determining the thermotectonic evolution of the region. Monazite, zircon, and garnet geochronology from each of the three major units within the Ruby Range reveal two distinct metamorphic age populations: an older population ca. 2.55-2.45 Ga (the Tendoy orogeny) and a second, younger population ca. 1.78-1.72 Ga (the Big Sky orogeny). Phase equilibria modeling for the Big Sky orogeny within the confines of the Mine Gulch 7.5’ quadrangle reveal discrete pressure-temperature (P-T)histories for each of the three major …