nyuuzyou/wikis huggingface dataset:
CSDMS 2014 annual meeting poster Arnaud Temme

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=A new soil-landscape model: focus on its subsurface architecture=
Arnaud Temme, Wageningen University Wageningen , Netherlands. arnaud.temme@wur.nlTom Vanwalleghem, University of Cordoba Cordoba , Spain. tom.vanwalleghem@uco.es
Abstract:
Landscapes are shaped by the combination of (vertical) soil development dynamics and (lateral) geomorphic processes. However, almost all landscape evolution modelling studies have seen soil as a homogenous quantity: the regolith. This positions geomorphic processes as first-order determinants of landscape forms, and leaves us with questions regarding the relative importance of soil development - despite ample anecdotal evidence of soil-affected geomorphology such as in landscapes with laterite formation or clay translocation. Luckily, some soil-landscape feedbacks are increasingly being included in models of landscape evolution. Here, we present a new 'soilscape' model that combines some parts of the landscale evolution model LAPSUS with most parts of the soil development model of MILESD. Example outputs are presented, but our focus is on the subsoil architecture in the new model, where we compare various alternatives to arrive at our choice: a finite number of layers of variable thickness, variable composition and variable bulk density.
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CSDMS 2014 annual meeting poster Barry Eakins

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Challenges in building coastal digital elevation models=
Barry Eakins, CIRES Boulder Colorado, United States. barry.eakins@colorado.eduPamela Grothe, Georgia Institute of Technology Atlanta Georgia, United States.
Abstract:
Digital elevation models support a wide variety of uses, including modeling of surface processes, habitat mapping and conservation planning, coastal change and terrain analysis, and Earth visualization and exploration. These models may, however, contain significant deviations from the surface they are intended to represent, which could reduce their usefulness. Additional complexities arise when integrating bathymetric and topographic data to create coastal DEMs. We identify common challenges in building square-cell, coastal DEMs, and present some solutions. These challenges are grouped into six general categories: (i) source data, (ii) data processing, (iii) model development, (iv) model assessment, (v) morphologic change, and (vi) model uncertainty. Some DEM best practices to help improve DEM accuracy and utility include: visual inspection of source data in a GIS environment; establishing common horizontal and vertical datums; using data buffers and bathymetric pre-surfaces; assessing DEM accuracy; accounting for morphologic change; and quantifying DEM uncertainty at the cell level.
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CSDMS 2014 annual meeting poster Ehab Meselhe

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Sediment Dynamics of the Lower Mississippi River: Understanding Sediment Availability and Delivery for Land Building=
Ehab Meselhe, The Water Institute of the Gulf Baton Rouge Louisiana, United States. emeselhe@thewaterinstitute.org
Abstract:
There is a dire need to use sediment from alluvial rivers to sustain and create new marsh, sustain barrier islands and ridges. Coastal Louisiana is a prime example where wetland loss rates are one of the highest worldwide. This presentation discusses the sediment dynamics of the Lower Mississippi River, specifically the sediment availability, temporal and spatial variability, as well as the sediment size characteristics. The investigation is performed using morphodynamic numerical tool (Delft3D). The Louisiana 2012 State Master Plan identified two viable mechanisms to build land, sediment diversions and dedicated dredging. The morphodynamic model has been parameterized and validated using historical and recent field observations. The model is being used to investigate the riverside morphological response to single or multiple dredging of lateral sand bars as well as the infilling pattern and rate. The model will also be used to identify the key design parameters that govern the sediment capture efficiency of sediment diversions, e.g. the alignment angle, invert elevation, diversion size, and location.
The uncertainty and limitations in the ability of the numerical model to adequately capture the relevant physical processes is discussed. The implications of such limitations on the decision making process is presented. Despite the limitations and uncertainties, the analysis provides valuable design recommendation for sediment diversions to maximize their sediment capture efficiency. The analysis also provides a management plan for dredging multiple borrow areas. The management plan includes coordination of dredging timeline among multiple borrow pits, as well as coordination between dredging activities and sediment diversion operation plans.
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CSDMS 2014 annual meeting poster Elchin Jafarov

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Using ground-penetrating radar to measure an ice-wedge depth=
Elchin Jafarov, National Snow and Ice Data Center Boulder Colorado, United States. elchin.jafarov@colorado.eduKevin Schaefer, National Snow and Ice Data Center Boulder Colorado, United States.Andrew Parsekian, University of Wyoming Wyoming, United States. 
Abstract:
We use 2-D forward finite-difference model of the ground-penetrating radar (GPR) to recover ice-wedge depth. The results of the inverse modeling of the synthetic ice-wedge depth showed convergence to the prescribed values. Here we present preliminary results of the synthetic ice-wedge depth recovery using genetic algorithm optimization subroutine. We also applied some noise to the synthetic data and showed up to what level of noise we were able to recover the desired depth. To evaluate the inverse method we calculate the corresponding uncertainties.
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CSDMS 2014 annual meeting poster Eunseo Choi

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=SNAC-CHILD Coupling: Preliminary Results Towards Interoperable Modeling Frameworks=
Eunseo Choi, Center for Earthquake Research and Information Memphis Tennessee, United States. echoi2@memphis.edu
Abstract:
Geodynamic modeling of the Earth’s subsurface provides critical boundary conditions for surface dynamics and deformation modeling, at various time scales. This in turn may be used to investigate the formation of specific landscape and geology configurations. Linking these two scientific tool chains, and the corresponding communities, through setting up an interoperability protocol between a framework for tectonic modeling applications, Pyre, and the CSDMS model coupling approach is one of the direct aims of the on-going EarthCube Building Blocks project, "Earth System Bridge: Spanning Scientific Communities with Interoperable Modeling Frameworks". I present preliminary works towards coupling SNAC, a Pyre-compatible application for tectonic modeling, with CHILD, a landscape evolution modeling code available as a component of the CSDMS Modeling Toolkit. As a proof of concept, a coupling scheme has been implemented without making explicit use of any framework. This simplistic coupling scheme is described, validated through non-trivial models, and discussed in terms of the interoperability of frameworks.
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CSDMS 2014 annual meeting poster Fei Xing

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Hydrodynamics and morphological changes of the Wax Lake Delta (WLD) during hurricane Rita, 2005=
Fei Xing, CSDMS Boulder Colorado, United States. Fei.Xing@colorado.eduAlbert Kettner, CSDMS Boulder Colorado, United States. kettner@colorado.eduJames Syvitski, CSDMS Boulder Colorado, United States. James.Syvitski@colorado.eduJohn Atkinson, Arcadis Boulder Colorado, United States. John.Atkinson@arcadis-us.com
Abstract:
For this study Delft3D HD module, coupled with SWAN and a morphology module is applied to explore the impact of hurricane Rita (2005) on the hydrodynamics and morphological changes of WLD, A vegetation routine is also incorporated to study the influence of plants during this hurricane event. Under normal conditions tides cause water level to change by ~1 m (-0.5 ~ 0.5 m). During hurricane Rita, the storm surge causes water level to rise to as high as 3 m. Water level at the deltaic area first decreases by more than 2 m before the hurricane storm surge approaches while water accumulates towards the center of the hurricane. Current velocity at the deltaic area increases from 0.6 m/s (during tides) to 1.5 m/s (during hurricane Rita), and the storm surge causes water to flow upstream in the river channels, lasting for 12 hours. Simulation results without including a vegetation routine reveal that after hurricane Rita made landfall, the delta morphology changed such that sediments eroded mostly on the deltaic islands and were deposited in the distributary channels. This demonstrates an opposite pattern to former observations made during river floods, indicating that hurricanes decrease the progradation of WLD. A model simulation incorporating aboveground vegetation shows that plants reduce storm surge progradation, and diminish the impact of hurricane Rita on the deltaic area such that the vegetated islands are less eroded. Less sediment is deposited in the distributary channels as well. The impact of plant roots has been explored through stabilizing bed materials, both for cohesive and non-cohesive sediments. Results demonstrate that roots can significantly decrease erosion in vegetated areas and illustrates that vegetation could be a great protector to wetlands, especially during extreme events.
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CSDMS 2014 annual meeting poster Harrison Gray

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=An iterative bleach-and-mix model for the change in luminescence signal with cumulative sediment transport.=
Harrison Gray, University of Colorado - Boulder Boulder Colorado, United States. harrison.gray@colorado.edu
Abstract:
Optically Stimulated Luminescence (OSL) dating is one member of a family of dating techniques that rely on sufficient sunlight exposure (bleaching) to remove a previously obtained signal. Sunlight exposure occurs during sediment transport from original erosional source to depositional sink and the presence of this signal bleaching is well-documented in the literature, yet, the mechanics of sunlight exposure in geomorphic systems has been unexplored. Since this bleaching of luminescence signal is a function of geomorphic variables such as transport rate, mechanism, and sediment flux, there exists potential to quantify these processes through measurement of the luminescence signal at various locations within a geomorphic system.
Here, I present a simple model demonstrating the predicted change in luminescence signal for a package of sediment with a homogeneous initial signal that is iteratively bleached at the surface and re-mixed. The model does not attempt to directly model a specific geomorphic environment, but is a starting point for predicting the magnitude and dispersion of luminescence signal values throughout a geomorphic system.
Initial model results demonstrate that the mean luminescence signal should decrease in a power law fashion asymptotically approaching zero with each mixing event. The standard deviation of the sediment package increases rapidly during the early mix and bleach iterations before leveling off and decreasing toward zero as the majority of the sediment reaches a homogeneously bleached state. Introducing a sediment flux into and out of the sediment package alters the geometry of the package and therefore the efficiency of bleaching causing the mean and standard deviation to approach steady-state values. This may suggest that the luminescence signals measured from sediment in transport act as a proxy for volumetric sediment fluxes. Combining this model with landscape evolution models may help predict the luminescence signal for fluvial networks which may in turn assist in provenance studies.
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CSDMS 2014 annual meeting poster Jaap Nienhuis

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Wave angle control on deltaic channel orientation=
Jaap Nienhuis, MIT-WHOI Cambridge Massachusetts, United States. jhn@mit.eduAndrew Ashton, WHOI Woods Hole Massachusetts, United States. aashton@whoi.eduLiviu Giosan, WHOI Woods Hole Massachusetts, United States. lgiosan@whoi.edu
Abstract:
Deltas are fragile coastal ecosystems, sensitive to changes in both marine and terrestrial forcings. Many active deltas face rising sea level, reduced fluvial sediment supply, and a subsiding delta plain, making them increasingly exposed to wave action. In a deltaic system, autogenic feedbacks between the river mouth, alongshore transport of sediment, and differential morphology between the up and downdrift flanks of the delta can deflect the river mouth and steer the course of the river. Previous modeling studies of wave-influenced deltas forced the fluvial channel to grow along a straight, predefined path, leaving these feedbacks unexplored.
We improve upon the plan-view delta Coastline Evolution Model (CEM) by allowing the river mouth to grow in a direction perpendicular to the local shoreline’s orientation. Additionally, a fraction of littoral sediment β can bypass the river mouth. This allows us study the effects of wave climate and sediment bypassing on channel orientation.
We find that for a large fluvial sediment flux the channel will orient itself into the dominant wave approach direction. In this case, shoreline angles on both sides of the river mouth effectively limit sediment bypassing. As fluvial dominance decreases, the channel steers away from the waves. When no littoral sediment is allowed to bypass the river mouth, the ratio between the flux of alongshore littoral sediment (stored in the updrift flank) and the flux of fluvial sediment (stored in the downdrift flank) is reflected by the average channel orientation. This physical framework allows us to further interpret the conditions under which deltas form. Furthermore, these results provide quantitative insight into active deltas under dynamic environmental conditions.
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CSDMS 2014 annual meeting poster Jean-Arthur Olive

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=The long-term evolution of normal faults controlled by lithospheric flexure and surface processes.=
Jean-Arthur Olive, MIT / WHOI Woods Hole Massachusetts, United States. jaolive@mit.eduMark Behn, WHOI Woods Hole Massachusetts, United States. mbehn@whoi.edu
Abstract:
We investigate the growth of normal faults on long timescales (10-1000 kyrs) and seek to identify key mechanical controls on fault dip, lifespan, and related topography. To do so, we consider the energy budget of a growing fault, which is partitioned into 1/ overcoming the frictional resistance on the fault and 2/ sustaining the build-up of topography and associated flexure. Our model builds on classic finite extension theory, but incorporates the possibility that the active fault plane may rotate as a response to the accumulation of flexural stresses with increasing extension. We postulate that fault plane rotation acts to minimize the amount of extensional work required to keep the fault active. In an elastic layer, this assumption results in rapid rotation of the active fault plane from ~60° down to 30–40° before fault heave has reached 40% of the faulted layer thickness. In our model, fault rotation rates scale as the inverse of the faulted layer thickness, which is in quantitative agreement with 2D geodynamic simulations that include an elasto-plastic description of the lithosphere. We show that fault rotation promotes longer-lived fault extension compared to continued slip on a high angle normal fault, and therefore holds a strong control on faulting styles (i.e., multiple short-offset vs. dominant large-offset faults). Finally, we incorporate erosion and deposition processes into the model, which locally enhance or relieve a portion of the topographic load, and characterize their influence on the evolution of extensional systems.
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CSDMS 2014 annual meeting poster Jian Hua Gao

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Changes in water and sediment exchange between the Changjiang River and Poyang Lake under natural and anthropogenic conditions, China=
Jian Hua Gao, Nanjing University Nanjing , China. jhgao@nju.edu.cnJianjun Jia, Key Laboratory of Submarine Geo-Sciences, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China Hangzhou , China.Albert J. Kettner, CSDMS Integration Facility, INSTAAR, University of Colorado, Boulder, CO 80309-0545, USA , United States.Fei Xing, CSDMS Integration Facility, INSTAAR, University of Colorado, Boulder, CO 80309-0545, USA , United States.
Abstract:
To study the fluvial interaction between Changjiang River and Poyang Lake, we analyze the observed changes of riverine flux of the mid-upstream of Changjiang River Catchment, Poyang Lake Watershed and Poyang Lake basin. Inter-annual and seasonal variation of the water discharge and sediment exchange processes between Changjiang River and Poyang Lake are systematically explored to determine the influence of climate change as well as human impact (especially the Three Gorge Dam (TGD)). Results indicate that climate variation for the Changjiang catchment and Poyang Lake Watershed is the main factor determining the changes of water exchanges between Changjiang River and Poyang Lake. However, human activities (including the emplacement of the TGD) accelerated this rate of change. Relative to previous years (1956-1989), the water discharge outflow from Poyang Lake during the dry season towards the Changjiang catchment increased by 8.98 km3 y-1 during 2003-2010. Evidently, the water discharge flowing into Poyang Lake during late April-late May decreased. As a consequence, water storage of Poyang Lake significantly reduced during late April-late May, resulting in frequent spring droughts after 2003. The freshwater flux of Changjiang River towards Poyang Lake is less during the flood season as well, significantly lowering the magnitude and frequency of the backflow of the Changjiang River during 2003-2010. Human activities, especially the emplacement and operation of the TGD and sand mining at Poyang Lake imposes a major impact on the variation of sediment exchange between Changjiang main river and Poyang Lake. On average, sediments from Changjiang River deposited in Poyang Lake before 2000. After 2000, Changjiang River no longer supplied sediment to Poyang Lake. As a consequence, the sediment load of Changjiang River entering the sea increasingly exists of sediments from Lake Poyang during 2003-2010. As a result, Poyang Lake converted from a depositional to an erosional system, with a gross sediment loss of 120.19 Mt y-1 during 2001-2010, including sand mining.
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CSDMS 2014 annual meeting poster Jianwei Han

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Measuring the imprint of orographic rainfall gradients on the morphology of steady-state numerical landscapes=
Jianwei Han, Tulane University New Orleans Louisiana, United States. jhan@tulane.eduNicole Gasparini, Tulane University New Orleans Louisiana, United States. ngaspari@tulane.eduJoel Johnson, The University of Texas at Austin Austin Texas, United States. joelj@jsg.utexas.edu
Abstract:
In this study we incorporate a 2-D orographic precipitation module into the CHILD numerical landscape evolution model to provide a quantitative tool for exploring the coevolution of rainfall patterns and fluvial topography, focusing on the imprint of spatial rainfall patterns on steady-state landscapes with uniform rock uplift. Our results suggest that network organization and planform morphology are strongly impacted by rainfall patterns. We find that rainfall gradients produce narrower watersheds, because channels show a tendency to flow along the rainfall gradient, rather than across it. The change in watershed shape is evidenced by smaller values of the exponent on distance in Hack’s law and a less peaked width function, which describes the distribution of points in a network at a given length from the outlet. Narrower watersheds also lead to an increase in the valley spacing ratio (mean mountain half width over mean distance between adjacent mainstem river outlets) and constrain trunk channels to follow a more direct path to the mountain foot. Rainfall gradients also influence the distribution of topography across a watershed. Channel profiles record rainfall patterns in both the channel concavity (downstream changes in slope) and the channel steepness index (ksn, or local slope normalized for drainage area). Small tributaries, in which the rainfall rate does not change as much relative to the mainstem channels, have a relatively clear relationship between ksn and mean rainfall across the tributary watershed. The hypsometric integral (HI), which increases with the amount of topography that is at relatively high elevations within a watershed, has a negative relationship with the profile concavity of the trunk channel, and high rainfall rates at the ridge top lead to mainstem channels that have relatively low concavity and watersheds with relatively higher HI in comparison with landscapes that have uniform precipitation. We contrast the impacts of rainfall patterns on landscape morphology with those resulting from a linear uplift gradient and uniform rainfall. We find that uplift patterns may have a similar impact on landscape morphology as rainfall gradients, making it challenging to decipher the relative roles of climate and tectonics on landscape evolution.
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