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

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Blocks control hillslope evolution in layered landscapes=
Rachel Glade, CU Boulder Boulder Colorado, United States. rachel.glade@colorado.edu
Abstract:
Rocky hillslopes dotted with large blocks and covered by a thin, non-uniform soil are common in both steep landscapes and arid environments, as well as on other planets. While the evolution of soil-mantled, convex hillslopes in uniform lithology can be well-modeled, the influence of lithology and geologic structure on hillslope form and evolution has yet to be properly addressed. Landscapes developed in layered rocks feature landforms such as mesas and hogbacks that exhibit steep, linear-to-concave up ramps scattered with blocks derived from the resistant rock layers. Beyond the ramp, no blocks are to be found. This morphology serves as a strong target for numerical modeling. Our hybrid continuum-discrete numerical model shows that interactions between resistant blocks and underlying easily weathered rock explain the form and evolution of a hogback, a tilted feature that exemplifies this class of landforms. Our model consists of a dipping hard rock layer sandwiched between less resistant layers. The hard layer releases resistant blocks that then armor the underlying rock from weathering. Fine sediment transport is treated with a traditional soil depth-dependent continuum hillslope flux law, while movement of individual resistant blocks is treated discretely. Blocks interfere with the flow of soil, damming it upslope, and developing a wake of thinning soil downslope into which the block eventually moves. We find that feedbacks between block release, weathering of blocks and soft rock, and sporadic downslope movement of blocks are necessary to capture the essence of these landscapes. Insights from our numerical model lead to a simple analytical solution that predicts the steady state hillslope form and slope angle from block size, spacing, rate of weathering, and the efficiency of soil transport. Our results illuminate previously unrecognized hillslope feedbacks, improving our understanding of the detailed geomorphology of rocky hillslopes and the large-scale evolution of landscapes developed in layered rock.
Hogback evolution through time in our numerical model, plotted every 400,000 years. The adjoining slope reaches steady state, parallel retreat by 1.6 Myr in which slope and release rate remain constant. Slopes are concave, with a slight convexity at the top. Blocks decrease in size as they weather and move downslope, and do not persist beyond the base of the ramp.
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CSDMS 2016 annual meeting poster RaleighMartin

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Linear scaling of wind-driven sand flux with shear stress=
Raleigh Martin, University of California, Los Angeles Los Angeles California, United States. Raleighmartin@gmail.comJasper Kok, University of California, Los Angeles Los Angeles California, United States. jfkok@ucla.edu
Abstract:
Wind-driven sand transport generates atmospheric dust and sculpts dunes, yet models for this process generally perform poorly. A paradigm underlying most such models is that particle speed increases linearly with wind shear velocity, resulting in the long-established nonlinear scaling of sand flux to the three-halves power of wind shear stress. Here, we present comprehensive measurements at three field sites showing that characteristic particle hop heights, and thus particle speeds, remain approximately constant with shear velocity. This result implies a linear dependence of wind-blown flux on wind shear stress, which we confirm by direct observation of the stress-flux relationship at all sites. Models for dust generation, dune migration, and other processes driven by wind-blown sand on Earth, Mars, and several other planetary surfaces should be modified to account for linear stress-flux scaling.
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CSDMS 2016 annual meeting poster RolfAalto

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Quaternary Morphodynamics of Fluvial Dispersal Systems Revealed: The Fly River, PNG, and the Sunda Shelf, SE Asia, simulated with the Massively Parallel GPU-based Model 'GULLEM'=
Rolf Aalto, Exeter, University of Exeter, United Kingdom. rolf.aalto@exeter.ac.uk
Abstract:
During glacial-marine transgressions vast volumes of sediment are deposited due to the infilling of lowland fluvial systems and shallow shelves, material that is removed during ensuing regressions. Modelling these processes would illuminate system morphodynamics, fluxes, and 'complexity' in response to base level change, yet such problems are computationally formidable. Environmental systems are characterized by strong interconnectivity, yet traditional supercomputers have slow inter-node communication -- whereas rapidly advancing Graphics Processing Unit (GPU) technology offers vastly higher (>100x) bandwidths. 
GULLEM (GpU-accelerated Lowland Landscape Evolution Model) employs massively parallel code to simulate coupled fluvial-landscape evolution for complex lowland river systems over large temporal and spatial scales. GULLEM models the accommodation space carved/infilled by representing a range of geomorphic processes, including: river & tributary incision within a multi-directional flow regime, non-linear diffusion, glacial-isostatic flexure, hydraulic geometry, tectonic deformation, sediment production, transport & deposition, and full 3D tracking of all resulting stratigraphy. 
Model results concur with the Holocene dynamics of the Fly River, PNG -- as documented with dated cores, sonar imaging of floodbasin stratigraphy, and the observations of topographic remnants from LGM conditions. Other supporting research was conducted along the Mekong River, the largest fluvial system of the Sunda Shelf. These and other field data provide tantalizing empirical glimpses into the lowland landscapes of large rivers during glacial-interglacial transitions, observations that can be explored with this powerful numerical model. 
GULLEM affords estimates for the timing and flux budgets within the Fly and Sunda Systems, illustrating complex internal system responses to the external forcing of sea level and climate. Furthermore, GULLEM can be applied to most ANY fluvial system to explore processes across a wide range of temporal and spatial scales. The presentation will provide insights (& many animations) illustrating river morphodynamics & resulting landscapes formed as a result of sea level oscillations.
http://www.geomorphology.com
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CSDMS 2016 annual meeting poster RyanSincavage

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=The quandary of an under-filled basin: Investigating the roles of local hydrology and incipient topography on channel path selection in Sylhet Basin, Bangladesh=
Ryan Sincavage, Vanderbilt University Nashville Tennessee, United States. ryan.s.sincavage@vanderbilt.eduMan Liang, University of Texas-Austin Austin Texas, United States. manliang@utexas.eduSteven Goodbred, Vanderbilt University Nashville Tennessee, United States. steven.goodbred@vanderbilt.eduPaola Passalacqua, University of Texas-Austin Austin Texas, United States. paola@austin.utexas.edu
Abstract:
Sylhet Basin, a seasonally flooded, tectonically influenced sub-basin within the Ganges-Brahmaputra-Meghna delta (GMBD) in northeastern Bangladesh, has experienced as many as three occupations of the Brahmaputra River during the Holocene. The active braidbelt has predominantly been routed along the proximal (west) margin of the basin, bypassing most of the water and sediment and leaving the central basin under-filled in spite of a favorable topographic gradient and active subsidence. We investigate this quandary with perturbations of several physical parameters within a simple 1D channel profile model and a 2D depth-averaged hydrodynamic model (FREHD) to determine preferential flow path selection between two possible pathways. A large body of water is created within the basin center to simulate seasonal flooding and to test the impact of a local backwater effect and reduced water surface slope on channel path preference. A hydrologic barrier effect does not appear to be plausible unless water depths are increased to values that exceed the physical dimensions of Sylhet Basin. Additionally, reduction of the topographic slope along two pathways in a simple bifurcation setup does not appear to enhance the local backwater effect on flow path selection. However, the introduction of a levee along the western margin flow path (and thus a lower elevation) than the basin center path creates a strong preference for bypass of the basin, in spite of a steeper path of descent towards the basin center. Additional tests on variable fan topography and asymmetry further illustrate the preference of the channel to follow a lower (entrenched) elevation bed surface, regardless of surface slope. These results corroborate field evidence in Sylhet Basin that antecedent topography within the GBMD exerts a primary control on Holocene river path selection, such that incision of the Pleistocene surface has impacted fluvial system dynamics more than local climate and tectonics. Future model runs will incorporate sediment transport to investigate the impacts of lake infilling on sediment bypass and mass extraction.
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CSDMS 2016 annual meeting poster SaiSiddharthaNudurupati

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Mechanisms of Shrub Encroachment explored in Southwestern United States using Landlab Ecohydrology=
Sai Siddhartha Nudurupati, University of Washington, Seattle, Washington, United States. saisiddu@uw.eduErkan Istanbulluoglu, University of Washington, Seattle, Washington, United States.Jordan M. Adams, Tulane University, New Orleans, Louisiana, United States.Daniel Hobley, University of Colorado, Boulder, Colorado, United States.Nicole M. Gasparini, Tulane University, New Orleans, Louisiana, United States. Gregory E. Tucker, University of Colorado, Boulder, Colorado, United States. Eric W. H. Hutton, CSDMS, University of Colorado, Boulder, Colorado, United States. 
Abstract:
Arid and semi-arid grasslands of southwestern United States have changed dramatically over the last 150 years due to woody plant encroachment. Driven by overgrazing, reduced fire frequency, and climate change, shrub encroachment is considered as a major form of desertification. In Landlab we represent ecohydrologic plant dynamics, fires, grazing, and resource distribution (erosion/deposition) in separate components. In this work, we demonstrate their utility for studying shrub encroachment using three examples. In the first example, a simple stochastic cellular automata model with two state variables, vegetation cover and soil resource storage, are used to model shrub patterns based on probabilistic establishment-mortality interplay, mediated by resource redistribution, while explicit roles of climate were neglected. In the second example, physically based vegetation dynamics model is used to simulate biomass production based on local soil moisture and potential evapotranspiration driven by daily simulated weather, coupled with a cellular automata plant establishment. While climate is included as forcing, the model disregards resource redistribution, except for seed dispersal. In the third example, we coupled the latter two models to examine the roles of disturbances and resource distribution in a dynamic ecohydrologic context. Inferences are drawn on how encroachment factors and model complexity affect shrub pattern in space and time.
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CSDMS 2016 annual meeting poster SalikAndersRosing

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Cretaceous Deepwater Formation: Processes and sensitivities=
Salik Anders Rosing, University of Copenhagen Copenhagen , Denmark, United States. salik@ign.ku.dkCourtney Harris, Virginia Institute of Marine Science Gloucester Point Virginia, United States. ckharris@vims.eduChristian J Bjerrum, Centre for Cross-disciplinary Chalk Research, Department of Geosciences and Natural Research Management, University of Copenhagen Copenhagen , Denmark. cjb@ign.ku.dk
Abstract:
It has been hypothesized that the warm Cretaceous Greenhouse climate with higher sea levels led to the breakdown of shelf front breaks and a thinning of the well mixed Ekman layer in continental shelf seas. Such a thinning would mean that shelf seas would have a more stratified structure, similar to that of the open oceans. With warmer climate, evaporation on stratified continental shelf seas could cause cascading of dense, high-salinity coastal waters, forming the oxygenated deep waters and leading to contour following currents in the intermediate waters below the pycnocline. Seismic surveys of the Upper Cretaceous Chalk group of the North Sea region suggest that the shallow Chalk Sea in which the group was deposited was under the influence of such contour following currents.
In order to test the hypothesis that dense water formation and cascading were a mechanism for deep water formation and contour following current forcing in the Chalk Sea, we developed an idealized model of the sea. The model, which was first proposed at the 2015 CSDMS meeting, simulates hydrodynamic and sediment transport processes, and is forced by climatic conditions (wind direction and strength, surface freshwater flux, salinity and temperature) informed by GCM modelling of the late Maastrichtian. Sediment properties are derived from experimental values. 
Here we present the final model and a range of sensitivity studies to demonstrate the feasibility of our hypothesis.
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CSDMS 2016 annual meeting poster SamapriyaRoy

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=A Composite Vulnerability Index for Urban Areas in Deltaic Regions: An Application in the Amazon Delta=
Samapriya Roy, Indiana University Bloomington Indiana, United States. roysam@indiana.edu
Abstract:
Deltas are complex socio-ecological systems subject to a wide range of human pressures and hazards, where population density is many-folds that of other regions. Urban development patterns, urban growth, river damming & sediment control coupled with climate change are increasing flood risks and the degree of vulnerability in many deltas of the world. The need for integrated vulnerability assessments that capture both socio-economic and geophysical elements in deltas is emergent. This study presents a composite index for the vulnerability assessment of the urban Amazon Delta (AD) based in three dimensions of vulnerability: flood exposure, socio-economic sensitivity and infrastructure. The vulnerability index was developed using the Analytical Hierarchy process (AHP), which helps to gage level of interdependence and the role of different dimensions of vulnerability. The index combines data from public databases at the most disaggregated level of analysis of census data (n = 2938 census sectors) and uses a methodology based on data from Shuttle Radar Topography Mission (SRTM) to assess and characterize sectors based on their flood risks. Results indicate that over 60% of the urban sectors within the AD present high degree of vulnerability, reaching a population of over one million inhabitants. This degree of urban vulnerability defines and reiterates the impacts of future climate changes across society and as it extends beyond the urban areas of the AD. The methodology proposed in this study contributes to a multi-dimensional assessment of urban vulnerability and it can be applied to other urban areas, allowing for cross-site comparison of vulnerabilities across urban spaces within deltaic systems. Depending on particular case study of an urban area, a more context specific sub set of model indicators can be selected to assess vulnerability. Some indicators can be adapted to individual urban systems thereby providing a useful tool to assess vulnerability in a particular case study while developing a broader model. Future work will involve additional emphasis on time dependent land cover changes and their effects on urban vulnerability based on compositional and configurational changes to the landscape.
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CSDMS 2016 annual meeting poster SantoshKumarMishra

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Climate Change Consequences on Seabird Population (With Emphasis on Distributional Changes in Seabirds in South Africa)=
Santosh Kumar Mishra, Population Education Resource Centre (PERC), Department of Continuing and Adult Education and Extension Work, S. N. D. T. Women's University, Mumbai, India. Mumbai , India. drskmishrain@yahoo.com
Abstract:
Climate change is already having a profound impact on the world’s oceans-disrupting the complex oceanographic phenomena and cycles that govern marine ecosystems. Seabirds are key indicators as to the magnitude of climate-induced changes in the marine realm, at the same time; they may also be uniquely vulnerable to its impacts. Numerous scenarios exist regarding the extent of climatic change consequences on seabird population. Over the past 100 years, the global mean surface temperature has increased by 0.6°C and scientists believe that there will be further increases 1.4 to 5.8°C over the next 100 years. Birds have already been affected by changes in breeding success, distribution and migration timing due to climate change. 
This paper aims to research into consequences climate change has on seabirds, responses, and predictions of future direct and indirect impacts. It also touches upon (as a case study) climate change impacts on distributional changes in seabird population in South Africa. In terms of methodology, secondary data have been used in this presentation and analysis is descriptive in nature. The paper concludes that along with impacts due to changes in weather, seabirds will also be indirectly affected by the impacts of climate change on their ecosystems. This includes the marine ecosystem that contains the main prey of seabirds and also the various ecosystems that provide the diverse range of seabird breeding habitats. Many predictions are based on the documented effects on seabirds during short warming events. With reference to climate change impacts on distributional changes in seabird population in South Africa, the paper finds that in the mid-1990s, breeding of Leach’s storm petrel Oceanodroma leucorhoa was recorded in the Western Cape, the first record for the Southern Hemisphere. Further, in the early 2000s, there was a decrease in numbers of Cape gannets Morus capensis breeding in the Western Cape, but a large increase in the Eastern Cape.
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CSDMS 2016 annual meeting poster SarahHarbert

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Investigating the role of near-fault relief and vertical uplift in strike-slip landscape development=
Sarah Harbert, University of Washington Seattle Washington, United States. harbert1@uw.eduAlison Duvall, University of Washington Seattle Washington, United States. aduvall@uw.eduGregory Tucker, University of Colorado - Boulder Boulder Colorado, United States. gtucker@colorado.edu
Abstract:
Strike-slip faults have long been observed to create distinctive fluvial landforms, such as offset, diverted, and captured streams, as well as near-fault relief features such as shutter ridges and sag ponds. These landforms, particularly offset streams, have been used to identify faults, assess fault activity and determine slip rates. However, not every active strike-slip fault shows a clear landscape signature of its presence, and strike-slip motion on a fault may not be wholly responsible for the occurrence and form of these features. Here, we attempt to constrain the factors that influence the production of strike-slip landforms. We use the Channel-Hillslope Integrated Landscape Development model (CHILD) to investigate specifically the effects of vertical uplift and relief across a fault. We model a scenario in which a strike-slip fault cuts a linear mountain ridge, offsetting a set of subparallel streams. By varying uplift rates and bedrock erodibility across the fault, we consider both how different ratios of vertical to horizontal fault motion affect the landscape and how the presence of landforms such as shutter ridges and sag ponds affect the development of the fluvial network along the fault, including stream offsets and capture events. 
Of the parameters tested, relief on the downhill side of the fault has the strongest effect on the landscape. When relief is low and shutter ridges are very small or not present, offsets are very short and stream capture occurs frequently. As a consequence, drainage spacing remains short because long offsets do not cause adjacent drainages to merge. We compare these results to landscapes in the Marlborough Fault System of New Zealand, which is a suite of four parallel strike-slip faults that vary in slip rate from 3 to 20 mm/yr from north to south. At sites analogous to our models, relief on the downhill side of the fault broadly correlates to channel offset length. These results show that the presence of topography or lithologic contrasts that can enhance the landscape signature of a strike-slip fault. Pre-existing characteristics of the landscape may damp or exaggerate the production of stream offsets and the occurrence of stream captures.
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