nyuuzyou/wikis huggingface dataset:
CSDMS 2014 annual meeting poster John Kondziolka

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Spatial structure and evolution in emergent vegetated ecosystems=
John Kondziolka, MIT Cambridge Massachusetts, United States. kondzi@mit.eduHeidi Nepf, MIT Cambridge Massachusetts, United States. hmnepf@mit.edu
Abstract:
Predicting how plant-water landscapes evolve through time is essential for development and restoration work involving natural ecosystems and built environments near waterways. Recent experimental studies show that the interaction and merger of vegetation patch wakes can produce zones of diminished velocity and enhanced deposition that persist downstream and are offset from the patch centerline, which may encourage lateral patterns of growth. These effects are not incorporated into current models of landscape evolution.
In this study, these flow-biogeomorphic interactions at the patch scale are incorporated into a simple model for vegetation development. The model is constructed in Matlab, utilizing MODFLOW, based on a porous media formulation for hydraulic resistance. Landscape evolution over 5 to 300 cycles of vegetation growth produces several categories of realistic landforms. The effect of wakes is shown to consistently alter the steady-state landscape reached by an environment, implying that current models underestimate the effects of vegetation on development.
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CSDMS 2014 annual meeting poster Julia Moriarty

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Buoyant and Gravity-Driven Transport on the Waipaoa Shelf: Model Evaluation and Sensitivity Analyses=
Julia Moriarty, Virginia Institute of Marine Science Gloucester Point Virginia, United States. moriarty@vims.eduCourtney Harris, Virginia Institute of Marine Science Gloucester Point Virginia, United States. ckharris@vims.eduCarl Friedrichs, Virginia Institute of Marine Science Gloucester Point Virginia, United States. cfried@vims.eduMark Hadfield, National Institute for Water and Atmosphere Wellington , New Zealand. m.hadfield@niwa.co.nz
Abstract:
Riverine deposits on continental shelves display terrestrial signatures, although the marine environment may overprint them. Partitioning between various transport mechanisms (dilute suspension vs. gravity-driven) may influence the location and characteristics of these deposits. The MARGINS Waipaoa River shelf initiative investigated these issues by conducting a thirteen month field campaign, and an ongoing numerical modeling study of the Waipaoa River shelf, New Zealand. We used two numerical models to analyze sediment fluxes and fate on the continental shelf during a time when three large floods and multiple high wave events occurred, from January 15, 2010 – February 15, 2011.
Water-column fluxes were estimated using the Regional Ocean Modeling System- Community Sediment Transport Modeling System (ROMS - CSTMS). This three-dimensional hydrodynamic-sediment transport numerical model accounted for gravity-driven transport by incorporating sediment concentrations into the model’s equation of state. Because ROMS did not resolve fluxes within the thin wave-current boundary layer, however, we also used a linear-bed turbid layer model based on the Chezy equation, which balances friction and gravity.
Buoyant fluxes within the water column model distributed sediment along-shore to the inner and mid-shelf, depositing material up to about 50 m water depth. Wave- and current- supported gravity flows, in contrast, could export sediment to long-term shelf depocenters (50 – 70 m water depth) and the continental slope. Hydrodynamic and seabed observations of sediment fluxes and gravity flows will be compared to sensitivity tests. Preliminary results indicated that erodibility parameterization and sediment settling velocity significantly affected buoyant sediment fluxes. In contrast, estimates from the near-bed turbid layer model were sensitive to assumptions about the distribution of sediment delivery from the river in terms of the initial deposit and percentage of the riverine load available for gravity driven transport.
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CSDMS 2014 annual meeting poster Kevin Hanegan

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Tidal Modulated Flow and Sediment Flux through Wax Lake Delta Distributary Channels: Implications for Delta Development=
Kevin Hanegan, University of New Orleans New Orleans Louisiana, United States. khanegan@uno.eduIoannis Georgiou, University of New Orleans New Orleans Louisiana, United States. igeorgio@uno.edu
Abstract:
In this study, a Delft3D model of the Wax Lake Delta was developed to simulate flow and sediment flux through delta distributary channels. The model was calibrated using existing measurements of velocity and sediment concentration across channel transects taken during a single flood event. The calibrated model was then used to simulate full spring-neap tidal cycles with several representative upstream boundary conditions, with grain size variation in suspended load represented using two sediment fractions. Flow and sediment flux results through distributary channel cross-sections were examined for spatial and temporal variability with the goal of characterizing delta development processes at the scale of a single bifurcation and along the entire channel network. The Wax Lake Delta has grown through channel extension, mid-channel bar deposition, and channel bifurcation. The formation of stable bifurcations in the delta has controlled the resulting channel network and landscape development. Model results at two particular bifurcations with varying degrees of asymmetry are examined in light of proposed equilibrium conditions. The flow and sediment flux distributions at both bifurcations show variability through the tidal cycle and at different input discharges. Additionally, the trends in flow, velocity, bed shear stress, and sediment transport are examined along primary distributary channels. Here we show that tidal modulation of currents influences suspended sand transport, and ebb-tide acceleration has the capacity to suspend sand in distal reaches during lower flows. The basinward-increasing transport capacity in Wax Lake Delta channels indicates that erosive channel extension could be an important process even during non-flood events. Results of this study show that tidal range and varying flow influence the balance between erosional and depositional delta growth. Modeling of these processes in existing deltas can increase the understanding of dynamics during low-flow portions of the year and their importance in delta development.
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CSDMS 2014 annual meeting poster Kimberly Rogers

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Simplifying the Ganges-Brahmaputra sediment dispersal system using a coupled model-field approach=
Kimberly Rogers, CSDMS Boulder Colorado, United States. kgrogers@colorado.eduIrina Overeem, CSDMS Boulder Colorado, United States. irina.overeem@colorado.edu
Abstract:
The Ganges-Brahmaputra (G-B) Delta is a densely populated (~900 km-2) delta that could be flooded within the next century by a combination of global sea level rise and increased monsoonal rains. These rivers currently transport a combined estimate of one billion tons of sediment from their basins in the Himalaya Mountains to the delta surface each year during the five months of the Asian summer monsoon. Sediment and water discharge has been reconstructed using observational data from two gauging stations on the Ganges and Brahmaputra Rivers from the mid 1950’s onward. However, downstream spatial distribution of sediment flux into the deltaic distributary channel network and deposition rates onto the floodplain and lower deltaplain are remarkably unconstrained, yet critical to understanding the overall delta sediment budget.
A series of model components are used to simplify the G-B sediment routing system and to test the sensitivity of the system to various climate scenarios. We numerically model daily and monthly incoming sediment flux with the climate-driven hydrological model, HydroTrend, which predicts long-term sediment load as a function of river discharge, drainage basin characteristics and climate controls. The estimated flux provides boundary conditions to the lowland sedimentary input system. We then present a simple approach to sediment routing over the delta distributaries and into tidal channels using two cross-sectional process models, AquaTellUS and FV-SED, to calculate cross-channel sediment accumulation from river flooding and tidal flooding, respectively. Model outputs are validated by field data collected in the fluvial-dominated and tidally-controlled lower delta plains. Direct sedimentation measurements from the river-dominated lower delta show spatially variable patterns of monsoonal overbank deposition, with localized rates as high as 5 cm/yr. In the tidally controlled western lower delta plain, regional mean accumulation rates are around 1 cm/yr, emphasizing the role of the large (3-4 m) tidal range in sediment dispersal. Seasonal sedimentation patterns revealed by these direct field measurements are comparable to rapid near-channel sedimentation indicated in the modeling results. Using this coupled modeling approach, the unknowns in the flood plain and deltaplain storage terms of the G-B sediment budget are simplified.
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CSDMS 2014 annual meeting poster Kristin Sweeney

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Testing bedrock incision models in a mixed bedrock-alluvial system: High Cascades, Oregon=
Kristin Sweeney, University of Oregon Eugene Oregon, United States. sweeney3@uoregon.edu
Abstract:
There is abundant field evidence that sediment supply controls the incision of bedrock channels by both protecting the bed from incision and providing tools to incise the bed. Mixed bedrock-alluvial systems are uniquely suited to test these models, as the transition from bedrock to alluvial morphology can constrain parameters like sediment supply that are otherwise difficult to measure. Here, we use Lidar data and field observations from a fluvial channel cut into a Holocene lava flow in the High Cascades, Oregon to explore the ability of the full physics of models of abrasion by saltating bedload to predict observed incision. The blocky andesite of Collier lava flow erupted from Collier Cone ~1500 years ago, paving over the existing landscape and erasing fine-scale landscape dissection. Since the eruption, a 6 km stream channel has been incised into the lava flow, though the channel is currently dry for most of the year. The channel is comprised of two alluvial reaches and two bedrock gorges. The division between these reaches follows the background slope of the lava flow, with alluvial areas corresponding to low slopes and gorges corresponding to high background slopes. The alluvial reaches are characterized by deposits up to 2 m thick and gravel-bedded self-formed channels; gorges are incised up to 8 m into the flow. Using a simple finite difference scheme with airborne-Lidar-derived pre-incision topography as an initial condition, we predict incision in the two gorges with the saltation-abrasion model. We examine model outcomes as a function of water discharge, grain size, and sediment supply, fully populating the parameter space with several model runs. Water discharge and grain size are set as free parameters and we use a 1D energy equation to calculate channel shear stress. To constrain sediment supply, we assume that there is no incision in the alluvial reaches, such that sediment supply is greater than or equal to alluvial transport capacity. Our initial results using this approach suggest that for most parameter values, gorge incision is dominated by the tools effect, whereby greater channel shear stress and greater sediment supply result in higher channel incision.
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CSDMS 2014 annual meeting poster Lian Feng

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Modeling the evolution of a thrust system: a geological application of DynEarthSol2D=
Lian Feng, University of Memphis Memphis Tennessee, United States. lfeng@memphis.eduEunseo Choi, University of Memphis Memphis Tennessee, United States. echoi2@memphis.eduMervin Bartholomew, University of Memphis Memphis Tennessee, United States. jbrthlm1@memphis.edu
Abstract:
DynEarthSol2D (an open source available at http://bitbucket.org/tan2/dynearthsol2) is a robust, adaptive, two-dimensional finite element code that solves the momentum and heat energy balance equations in the Lagrangian form using unstructured meshes. Verified in a number of benchmark problems, this solver uses contingent mesh adaptivity in places where shear strain is focused (localization) and a conservative mapping assisted by marker particles to preserve phase boundaries during remeshing. As a first step towards the ultimate goal of applying DynEarthSol2D to the tectonics-surface process coupling, we explored the role of spatial distribution of décollements on structural styles of a thrust system. In our models, a décollement is a gliding zone of accumulated high shear strain, originating from an incompetent layer with a lower cohesion and friction angle than its surrounding rock. Models of various spacing between décollements develop dramatically different subsequent structures with a spectrum of three characteristic styles of thrust systems: ramp-flat thrust, imbricate thrust, and duplex. We also investigate how erosion rates and overburden influence thrusting patterns.
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CSDMS 2014 annual meeting poster Mary Hill

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Exploring how parameter importance to prediction changes in parameter space=
Mary Hill, USGS Boulder Colorado, United States. mchill@usgs.govOlda Rakovec, UFZ Liepzig , Germany. oldrich.rakovec@ufz.deMartyn Clark, NCAR Boulder Colorado, United States. mclark@ucar.edu
Abstract:
This talk presents a novel hybrid local-global method that measures how model parameter importance is distributed as parameter values change. DELSA (Distributed Evaluation of Local Sensitivity Analysis) is demonstrated using rainfall-runoff models constricted using FUSE, and results are compared to the Sobol’ global sensitivity analysis method. Insights from DELSA can be combined with field data to identify the most relevant parts of parameter space to focus data collection and model development.
Much of what will be discussed is described in:
Rakovec, O., M. C. Hill, M. P. Clark, A. H. Weerts, A. J. Teuling, and R. Uijlenhoet (2014), Distributed Evaluation of Local Sensitivity Analysis (DELSA), with application to hydrologic models, Water Resources Research, 50, doi:10.1002/2013WR014063.
Comparing Sobol' to the less computationally demanding DELSA method.
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CSDMS 2014 annual meeting poster Phaedra Upton

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=How does topography control shallow geological processes?=
Phaedra Upton, GNS Science Lower Hutt , New Zealand. p.upton@gns.cri.nzPeter Koons, University of Maine Orono Maine, United States. peter.koons@maine.eduJamie Howarth, GNS Science Lower Hutt NO STATE, New Zealand. j.howarth@gns.cri.nz
Abstract:
Over the past 30 years conceptual and numerical models of crustal evolution have evolved from simple 2D cross-sections to complex 3D models that achieve a qualitative, process-based understanding of key aspects of solid earth dynamics. However, recent progress toward improved application of these models to higher spatial and temporal frequencies has revealed considerable inconsistencies in their predictive powers, especially at the near surface. Here we focus on how topography at the scale of ridges and valleys feedback into the 3D stress and strain fields and related parameters. A new formulation, the Failure Earth Response Model (FERM), which unifies the description of tectonic and geomorphic forcings within a single framework, allows us to gather stresses generated by far field tectonics processes, topography and surface processes into a single stress state for every point. We can explicitly consider the contribution that pore pressure fluctuations, seismic accelerations, fault damage and large storm events make toward the rock mass failing using examples from the Southern Alps of New Zealand.
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CSDMS 2014 annual meeting poster Sagy Cohen

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=On the sensitivity of global suspended sediment modeling to dams=
Sagy Cohen, University of Alabama Tuscaloosa Alabama, United States. sagy.cohen@ua.eduJames Syvitski, University of Colorado Boulder Colorado, United States.Albert Kettner, University of Colorado Boulder Colorado, United States.
Abstract:
The WBMsed model is a global, spatially and temporally explicit riverine flux (water, sediment and nutrients) simulator. Among its many input datasets is a dams and reservoir dataset, used to calculates the water balance and the upstream sediment trapping efficiency of a river system. Here we compare results from three simulations: (1) no reservoirs input, (2) the model's original reservoirs input that include only large dams, and (3) a new dam dataset to include over 6600 large and small dams worldwide. The new dams input is based on the Global Reservoir and Dam (GRanD) Database (http://sedac.ciesin.columbia.edu/data/collection/grand-v1). As expected, the results show that simulations that include dams yields a more accurate predictions of modern fluxes. The results also show that the new dataset have significantly improved the model accuracy in some rivers while having a neutral or, in some cases, negative effect in others.
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CSDMS 2014 annual meeting poster Sai Siddhartha Nudurupati

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Coupling Fluvial and Eco-hydrologic Components in the Landlab Modeling Framework=
Sai Siddhartha Nudurupati, University of Washington Seattle Washington, United States. saisiddu@gmail.comErkan Istanbulluoglu, Unviersity of Washington Seattle Washington, United States. erkani@u.washington.eduGreg Tucker, University of Colorado & CIRES Boulder Colorado, United States. gtucker@colorado.eduNicole Gasparini, Tulane University New Orleans Louisiana, United States. ngaspari@tulane.eduEric Hutton, CSDMS Boulder Colorado, United States. hutton.eric@gmail.comDan Hobley, University of Colorado Boulder Colorado, United States. Daniel.Hobley@colorado.eduJordan Adams, Tulane University New Orleans Louisiana, United States. <smmall>jadams15@tulane.edu</small>
Abstract:
In arid and semi-arid regions, geomorphic response of a catchment is tightly coupled with Eco-hydrologic dynamics. Climate-driven biotic and abiotic processes strongly influence land-surface-atmosphere interactions and thus play an important role in landscape evolution. Landscape Evolution Models (LEMs) provide a platform for scientists to quantitatively understand these complex interactions by exploring testable hypotheses. Hydrology and vegetation dynamics are thus critical components of these LEMs. This work illustrates the development of such components and model-building by coupling fluvial and ecohydrologic components in the Landlab modeling environment. The Landlab is a component based framework for 2D numerical modeling, coded in Python. It provides a gridding module and allows users to either configure a model from scratch or use existing components. We present a coupled overland flow and vegetation dynamics model where vegetation is simulated based on inputs from stochastic precipitation generator, radiation component, potential evapotranspiration component and soil moisture component, and runoff is routed by overland flow component. This work demonstrates the flexibility of the Landlab and also highlights the advantages of component-based approach.
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CSDMS 2014 annual meeting poster Salik Anders Rosing

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Modeling the circulation of the NW European shelf seas – present and deep past.=
Salik Anders Rosing, University of Copenhagen Copenhagen , Denmark. salik@ign.ku.dkChristian J. Bjerrum, University of Copenhagen Copenhagen , Denmark. cjb@ign.ku.dkMuchamad Al Azhar, University of Copenhagen Copenhagen , Denmark. azhar.al@gmail.com
Abstract:
The present day North Sea is here explored through the basic modelling capacities of the Regional Ocean Modeling System (ROMS) coupled with the biogeochemical sub module of Azhar et al., 2014. This new module is capable of investigating low oxygenanoxic bottom water conditions such as under upwelling or eutrophic systems.
The prospect of the study is to provide a ground truth case for the model toward reproducing known circulation, productivity, oxygenation and bottom sediment distribution patterns in the basin, and if successful, to study the effect of predicted sea level change under a changing future climate. These investigations will be used as a back drop for modelling the Cretaceous of Northwest Europe, in order to investigate the effect of climate and bathymetry on productivity, bottom water conditions and carbonate ooze deposition in the region.
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