nyuuzyou/wikis huggingface dataset:
CSDMS 2016 annual meeting poster HuiTang

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=GeoClawSed: A Model with Finite Volume Method for Tsunami Sediment Transport=
Hui Tang, V Blacksburg Virginia, United States. tanghui@vt.eduRobert Weiss, Virginia Tech Blacksburg Virginia, United States. weiszr@vt.edu
Abstract:
The shallow-water and advection-diffusion equations are commonly used for tsunami sediment-transport modeling. GeoClawSed is based on GeoClaw and adds a bed updating and avalanching scheme to the two-dimensional coupled system combining the shallow- water and advection-diffusion equations, which is a set of hyperbolic integral conservation laws. The modeling system consists of three coupled model components: (1) the shallow-water equations for hydrodynamics; (2) advection-diffusion equation for sediment transport; and (3) an equation for morphodynamics. For the hydrodynamic part, the finite-volume wave propagation methods (high resolution Godunov-type methods) are applied to the shallow-water equations. The well-known Riemann solver in GeoClaw is capable of dealing with diverse flow regimes present during tsunami flows. For the sediment-transport part, the advection-diffusion equation is employed to calculate the distribution of sediment in the water column. In the fully-coupled version, the advection-diffusion equation is also included in the Riemann solver. The Van Leer method is applied for calculating sediment flux in each direction. The bed updating and avalanching scheme (morphodynamics) is used for updating topography during tsunami wave propagation. Adaptive refinement method is extended to hydrodynamic part, sediment transport model and topography. GeoClawSed can evolve different resolution and accurately capture discontinuities in both flow dynamic and sediment transport. Together, GeoClawSed is designed for modeling tsunami propagation, inundation, sediment transport as well as topography change. Finally, GeoClawSed is applied for studying marine and terrestrial deposit distribution after tsunami wave.
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CSDMS 2016 annual meeting poster JaapNienhuis

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Predicting coastal deltaic change on a global scale=
Jaap Nienhuis, Tulane University New Orleans Louisiana, United States. jnienhui@tulane.eduAndrew Ashton, Woods Hole Oceanographic Institution Woods Hole Massachusetts, United States. aashton@whoi.eduAlbert Kettner, University of Colorado, Boulder Boulder Colorado, United States. kettner@colorado.eduDouglas Edmonds, Indiana University Bloomington Indiana, United States. edmondsd@indiana.eduJoel Rowland, Los Alamos National Laboratory Los alamos New Mexico, United States. jrowland@lanl.govTor Törnqvist, Tulane University New Orleans Louisiana, United States. tor@tulane.edu
Abstract:
Coastal deltaic change is expected to be one of the major Earth-surface hazards of the 21st century as deltas around the world face large changes in sediment supply due to river damming, land-use changes, and climate change. We have quantified the effect of waves, tides, and fluvial sediment supply on delta morphology to predict future changes to deltaic coasts. Simple parameterizations and key insights from global wave, tide, and fluvial sediment data have allowed us to make morphologic predictions around the globe for every delta on Earth. We find that without human interference many deltas with decreased sediment loads are expected to be reworked by waves into barrier islands or by tides into alluvial estuaries. Other deltas are projected to experience increased sediment flux, and, in some cases these growing deltas could transition to river-dominated morphologies. This unified, global picture of future deltaic change will aid local management of deltaic areas and also provide opportunities for inclusion of morphologic change into Earth system and climate models.
(A) Predicted morphology of about 14000 deltas/river mouths globally. (B) Location in the Galloway Ternary diagram set by the wave, tide and fluvial sediment fluxes. Color and size indicate the fluvial sediment flux, a proxy for delta area. (C) Number of channels for a selection of the 14000 deltas.
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CSDMS 2016 annual meeting poster JeremyKerr

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Investigating the relationship between carbonate facies belts and mosaics=
Jeremy Kerr, Nova Southeastern University Dania Florida, United States. jk908@nova.edu
Abstract:
The spatial patterns of facies within a carbonate depositional system provide a geologic record of climatic and oceanographic conditions. The classic textbook model describes such a system as a series of shore- or margin-parallel facies belts whose occurrence strongly correlates with water depth. While clearly useful for describing broad-scale spatial patterns and reconstructing geologic history, including sea-level curves, the belt model does not adequately capture the fine-scale spatial heterogeneity of facies arrangements observed in real-world systems. This limitation of the belt model led to the proposal the facies mosaic model as an alternative description for carbonate depositional systems. A facies mosaic is defined as, “an arrangement of lithological elements lacking significant linear trends in element arrangement, but showing some statistically significant relationship between element size and frequency of occurrence.” This definition is a useful starting point for refining our understanding of these sedimentary systems, yet it too is limited. In particular, there is an implicit assumption that belt systems and mosaics are distinct end-members on a spectrum of possible facies configurations, yet it remains unclear whether this assumption is true or not. Further muddling the issue is the fact that facies belts can exhibit the statistically significant relationship between element size and frequency of occurrence inherent to the mosaic model. Thus, there is a need to revisit these two models to better understand their relationship to address the aforementioned issues. This is important because if they do represent distinct configurations, then one must ask if they represent different sets of environmental controls. If they do, then the criteria for distinguishing the two endmembers require refinement to ensure reliable interpretation of the sedimentary record. This study investigates the relationship between the belt and mosaic models using real-world observations of lateral facies patterns from a modern isolated carbonate platform.
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CSDMS 2016 annual meeting poster JohnShaw

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=A mass-conservation approach to predicting the distance to river mouth channel bifurcations=
John Shaw, University of Arkansas Fayetteville Arkansas, United States. shaw84@uark.eduBrandon McElroy, University of Wyoming Laramie Wyoming, United States. bmcelroy@uwyo.eduKim Miller, University of Wyoming Laramie Wyoming, United States. litwinmiller@gmail.com
Abstract:
Channel bifurcation is an important process in fluvio-deltaic morphodynamics and resulting stratigraphic architecture of prograding river deltas. We develop and test a new theory for the formation of channel bifurcations based on fluid mass conservation and system-averaged transport conditions rather than local hydrodynamics. 29 experimental deltas were built under a variety of boundary conditions to examine the inception and growth of bars and channel bifurcations. From the initial condition of water and sediment entering a still basin of uniform depth as a wall-bounded turbulent jet, delta growth begins with the formation of a lunate bar as predicted by the hydrodynamics of jet spreading. However, the lunate bar diverts water and sediment laterally causing the bar to widen into a radially symmetric flow expansion extending from the channel axis to the flume walls. This feature is stable to perturbations, and its distal limit progrades basinward while maintaining a roughly constant flow depth of ~10 times the median grain diameter (H=2-3 mm). Bar formation and channel bifurcation occur on top of the apron at the distance where shear stress applied by radially-averaged flow velocity falls below the threshold of sediment motion. Our model predicts that the distance to the first channel bifurcation should scale with water discharge, scale inversely with flow depth over the apron, and scale with median grain diameter to the negative one half.
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CSDMS 2016 annual meeting poster JuanFelipePaniagua-Arroyave

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Prediction of coastline retreat in Arboletes, southern Caribbean coast of Colombia, for a climate change scenario=
Juan Felipe Paniagua-Arroyave, University of Florida Gainesville Florida, United States, Colombia, Spain. jf.paniagua@ufl.eduIvan Dario Correa, Universidad EAFIT Medellin , Colombia. icorrea@eafit.edu.coPeter Adams, University of Florida Gainesville Florida, United States. adamsp@ufl.eduGiorgio Anfuso, Universidad de Cadiz Puerto Real , Spain. giorgio.anfuso@uca.es
Abstract:
Accurate quantification of coastal hazards remains a crucial issue in the light of predicted future sea level rise due to climate change. Most drastic up-to-date predictions have proposed for 2100 a global mean sea level in ~1 m above pre-industrial levels. This may increase the likelihood of related coastal impacts, especially on vulnerable coastlines of developing countries. Along the soft-cliffs of Arboletes town, southern Caribbean coast of Colombia, recent research has quantified historical retreat rates and predicted future coastline positions for the climate change related acceleration in global mean sea level.
The aim of present study is to improve upon those results by including a more accurate quantification of local mean sea level rise and variations in top-cliff coastline elevations. Latter item allowed the calculation, under several assumptions, of the amount of sediment that would be released to the nearshore from cliff erosion. By using a validated model that relates the rates of retreat and sea-level rise, future positions were calculated for ~1 km of coastline located at the Minuto de Dios neighborhood (MD) of Arboletes town. Overall, mean end-point retreat at MD between 1938 and 2010 was 1.7±0.4 m/a, which would increase to 2.9±0.7 m/a between 2010 and 2046 due to the acceleration in global mean sea level rise. This may imply a future mean coastline recession distance of 104.4±25.2 m and a release of 720,000 m3 of rock.
Future coastline retreat of the order of magnitude herein presented could produce important impacts over local infrastructure, including the loss of around 100 socio-economically vulnerable urban constructions of MD. In addition, 2046 coastline may be located as close as 50 m from the main road that connects Arboletes town with Monteria city. To the knowledge of the authors, these predictions provide compelling evidence that climate change may exacerbate already important coastal hazards along the littoral of MD. Indeed, aforementioned results may inform policy makers and could eventually lead to coastal management solutions for this region.
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CSDMS 2016 annual meeting poster JuliaMoriarty

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=The Roles of Resuspension and Redistribution on Nutrient Cycling in the Northern Gulf of Mexico: Results From A Coupled Hydrodynamic-Sediment Transport – Biogeochemical Numerical Model=
Julia Moriarty, Virginia Institute of Marine Science, College of William & Mary Hayes Virginia, United States. moriarty@vims.eduCourtney Harris, Virginia Institute of Marine Science, College of William & Mary Hayes Virginia, United States. ckharris@vims.eduMarjorie Friedrichs, Virginia Institute of Marine Science, College of William & Mary Hayes Virginia, United States. marjy@vims.edu
Abstract:
Transport of particulate organic matter within and through coastal marine environments depends on the relative effects of supply, storage in the seabed, subsequent resuspension, and advection within the water column, as well as biogeochemical reactions. These transport processes are often invoked to explain spatial or temporal variations in biogeochemical fluxes, but the extent to which resuspension and advection affect water-column biogeochemistry and carbon remineralization is debated and can be challenging to measure. A modeling approach promises a means of quantifying these fluxes for a range of conditions, and enables extrapolation beyond point observations. Typically, however, water column biogeochemistry models have used simplifying assumptions to represent benthic boundary conditions, and have neglected resuspension and subsequent advection of particulate organic matter and nutrients. Yet, sensitivity tests have shown that estimates of biogeochemical cycling in dynamic coastal environments are sensitive to how sediment processes are represented in models. 
To evaluate the role of seabed resuspension and subsequent advection on biogeochemical fluxes, we developed a coupled model within the Regional Ocean Modeling System (ROMS) framework. The coupled model includes hydrodynamic, sediment transport, and biogeochemical processes. To link the sediment transport and water column biogeochemical modules, a diagenetic model was added to the seabed. The coupled model accounts for processes including advection, resuspension, diffusion within the seabed and at the sediment-water interface, and organic matter remineralization. Here, we implemented coupling between hydrodynamics, sediment transport, and a biogeochemical model within a full three-dimensional numerical model to investigate the relative effects of supply, resuspension, and advection on biogeochemical fluxes within the riverine-influenced Gulf of Mexico. Preliminary results indicate that seabed and bottom boundary layer oxygen consumption increased where and when particulate organic carbon accumulates on the shelf. Ongoing work includes analyzing results for nitrogen fluxes and from time-periods with low-oxygen conditions.
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CSDMS 2016 annual meeting poster KatherineRatliff

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Exploring delta morphodynamics with a coupled river-ocean model=
Katherine Ratliff, Duke University Durham North Carolina, United States. k.ratliff@duke.eduEric Hutton, CSDMS Boulder CO Colorado, United States. eric.hutton@colorado.eduBrad Murray, Duke University Durham North Carolina, United States. abmurray@duke.edu
Abstract:
Often densely populated, deltas are important for agriculture, resource extraction, and transportation, yet they are increasingly vulnerable to natural disasters (e.g., flooding, storm surges) and submergence. Many natural processes influence large-scale delta morphology, yet the relative importance of anthropogenic influences in shaping modern deltas is unknown. To explore the long-term combined effects of sea-level rise, climate change, and anthropogenic influences, we have developed a new morphodynamic delta model that links fluvial, floodplain, and coastal dynamics over large space and timescales. Using the CSDMS Basic Modeling Interface, we couple the River Avulsion and Floodplain Evolution Model (RAFEM) with the Coastline Evolution Model (CEM). In RAFEM, the river course is determined using steepest-descent methodology, and elevation changes along the river profile are modeled as a linear diffusive process. An avulsion occurs when the riverbed becomes super-elevated relative to the surrounding floodplain, but only if the new steepest-descent path to sea level is shorter than the prior river course. CEM uses alongshore sediment transport gradients to distribute sediment flux from the river mouth along the coastline. Preliminary results indicate that anthropogenic manipulations of the river (e.g., levees) can propagate hundreds of kilometers upstream and affect shoreline morphology. Climate change impacts on delta morphology are modeled through changing storminess (affecting the wave climate) and varying sea-level rise rates.
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CSDMS 2016 annual meeting poster KenFerrier

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Transient responses of chemical erosion rates to perturbations in physical erosion rates in a simple model of regolith mineralogy=
Ken Ferrier, Georgia Tech Atlanta Georgia, United States. ken.ferrier@eas.gatech.edu
Abstract:
Regolith-mantled hillslopes respond to tectonic and climatic perturbations in a variety of ways over a variety of time scales. Here I explore the response of chemical erosion rates in regolith to transient perturbations in physical erosion rates using a simple numerical model for regolith mineralogy. In this 1-D column model, weathered regolith is eroded from the surface at a prescribed physical erosion rate E(t), which drives responses in the rate at which solutes are flushed from the regolith at a chemical erosion rate W(t). To explore the response of W to perturbations in E, I impose a Gaussian pulse in physical erosion rates and compute the time-varying response in W. This model predicts that changes in W lag changes in E by a time comparable to the regolith residence time. As a consequence of this lag, there is a hysteresis in the modeled response of W to perturbations in E, with different relationships between W and E over different periods of time during and after the pulse. This model also predicts that the resulting relationships between W and E should depend on the initial value of E relative to a maximum possible regolith production rate. That is, transient increases in E generate increases in W for some initial values of E, and generate decreases in W for other initial values of E. To the extent that this model reflects the behavior of chemical erosion rates in nature, these results imply that transient perturbations in physical erosion rates can complicate interpretation of the relationships between W and E inferred from fluvial solute and sediment flux measurements and from sediment cores.
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CSDMS 2016 annual meeting poster KimberlyMiller

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Experimental reproducibility of results of flow intermittency on delta dynamics=
Kimberly Miller, University of Wyoming Encino California, United States. litwinmiller@gmail.comBrandon McElroy, University of Wyoming Laramie Wyoming, United States. Wonsuck Kim, University of Texas at Austin Austin Texas, United States. 
Abstract:
In order to simplify the complex hydrological variability of flow conditions, experiments modeling delta evolution are often conducted using a representative “channel-forming” flood flow and then results are related to field settings using an intermittency factor, defined as the fraction of total time at flood conditions. Although this intermittency factor makes it easier to investigate how variables, such as relative base level and/or sediment supply, affect delta dynamics, little is known about how this generalization to a single flow condition affects delta processes. With changes in climate causing changes in magnitude, as well as variability, of the hydrology of these coastal systems, it is important to understand how intermittent flows will affect these environments. We conducted a set of laboratory experiments with periodic flow conditions to determine the effects of intermittent discharges on delta evolution. Because the Sediment Experimentalist Network (SEN) has stated that reproducibility of experimental results is one of the grand challenges facing our scientific community, we have conducted similar experiments at both the University of Texas at Austin and the University of Wyoming to compare and determine generalized conclusions. During these experiments, flood periods with a set water discharge and sediment supply, cycles between periods of base flow where the sediment supply is turned off. We find that during base flow periods, channels tend to incise resulting in a small yet finite amount of shoreline progradation even though sediment is not input to the system. On the other hand, channels will aggrade during floods when sediment is turned back on. The system must adjust between these two different equilibrium states for each flow condition. These results suggest that the adjustment timescale between differing flow conditions is a factor in determining the overall shape of the delta and behavior of the fluviodeltaic channels. We conclude, periods of base flow when topset sediment is reworked, may be just as important to delta dynamics as periods of flood when sediment is supplied to the system.
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