nyuuzyou/wikis huggingface dataset:
CSDMS 2014 annual meeting poster Shimelis Setegn

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Hydrological model application and prediction uncertainty analysis=
Shimelis Setegn, Florida International University Miami Florida, United States. ssetegn@fiu.edu
Abstract:
The main objective of this study was to assess the performance and applicability of the soil water assessment tool (SWAT) model for prediction of streamflow in the Lake Tana Basin, so that the influence of topography, land use, soil and climatic condition on the hydrology of Lake Tana Basin can be well examined. Sequential uncertainty fitting (SUFI-2), parameter solution (ParaSol) and generalized likelihood uncertainty estimation (GLUE) calibration and uncertainty analysis methods were compared and used for the set-up of the SWAT model.
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CSDMS 2014 annual meeting poster Stephanie Higgins

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=InSAR measurements of compaction and subsidence in the Ganges-Brahmaputra Delta, Bangladesh=
Stephanie Higgins, University of Colorado Boulder Boulder Colorado, United States. stephanie.higgins@colorado.edu
Abstract:
The Ganges-Brahmaputra Delta (GBD) is the world's largest river delta, and is home to more than 150 million people. This study reconstructs subsidence rates in the eastern portion of the Ganges-Brahmaputra Delta (GBD), Bangladesh, covering more than 10,000 km2 at a high spatial resolution of 100 m. The map was produced using Interferometric Synthetic Aperture Radar (InSAR) covering the period 2007 to 2011. Eighteen ALOS (Advanced Land Observing Satellite) PALSAR (Phased-Array L-band SAR) scenes were used to generate 30 interferograms calibrated with GPS. Interferograms were stacked to yield average subsidence rates over the study period. Small Baseline Subset (SBAS)-InSAR was then applied to validate the results against an additional GPS record from Dhaka, Bangladesh. Land subsidence of 0 to > 10 mm/y is seen in Dhaka, likely related to groundwater abstraction with rates corresponding to local variations in shallow subsurface sediment properties. Outside of the city, rates vary from 0 to > 18 mm/y, with the lowest rates appearing primarily in Pleistocene Madhupur Clay and the highest rates in Holocene organic-rich muds. Results demonstrate that subsidence in this delta is primarily controlled by local stratigraphy, with rates varying by more than an order of magnitude depending on lithology. The ability of L-band InSAR to differentiate between stratigraphic units in this humid, vegetated subtropical river delta demonstrates the power of interferometry as a tool for studying the subsurface in deltaic environments.
(a) InSAR-derived average annual subsidence rates in the city of Dhaka, underlain by a satellite image of the city.(b) NEHRP soil class in the city of Dhaka, from CDMP [2009].Class D1 soil is most stiff, and class E soil is least stiff.
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CSDMS 2014 annual meeting poster Tara Kniskern

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Advances in sediment transport modeling offshore of a fluvial source=
Tara Kniskern, Virginia Institute of Marine Science PO Box 1346 Virginia, United States. knista@vims.eduCourtney Harris, Virginia Institute of Marine Science Gloucester Point Virginia, United States. ckharris@vims.eduJustin Birchler, Virgina Institute of Marine Science Gloucester Point Virginia, United States. jjbirchler@vims.edu
Abstract:
The Community Sediment Transport Modeling System (CSTMS) has been applied to several continental shelf environments, including areas offshore of large river sources. However, all of these sediment transport model studies have represented sediment as non-reactive tracers, resulting in a disconnection between model calculations and field observations which may rely on geochronological tracers. Additionally, model estimates of sediment transport within the freshwater plume, or resuspended on the sediment bed have not been linked to cross-shelf transport mechanisms that carry material to the deep sea. Here we make advances on both fronts by developing a numerical model for suspended transport that will be linked to models of down-slope transport, and furthermore develop the ability to directly estimate transport and decay of particle reactive radionuclides.
To better understand transport pathways and depositional patterns in the Gulf of Mexico, a three-dimensional coupled hydrodynamic-sediment transport model has been developed within the Regional Ocean Modeling System (ROMS). The modeled period, October 2007 through September 2008, included two hurricanes and a period of high river discharge. Model estimates of sediment dispersal revealed sensitivities to settling velocities and critical bed shear stresses. Transport and deposition of terrestrial sediments were limited along-shelf, such that the model showed little comingling of material from the Mississippi, Atchafalaya, and Mobile Rivers during the yearlong model run. Across-shelf suspended sediment transport occurred primarily during periods of elevated wave heights, coincident with storms.
The relative influences of terrestrial and marine processes on sediments in coastal marine environments can be inferred from the distribution of short-lived radioisotopes, but these have not previously been represented within models. A one-dimensional (vertical) sediment transport model was modified to include Be-7, a proxy for terrestrial sources, and Th-234, a proxy for suspension in marine environments, as reactive tracers associated with sediment particles. Experimental results explored the sensitivity of vertical radioisotope profiles to initial deposit thickness, bioturbation rates, resuspension depths, and initial radioisotope inventories. This approach will facilitate better comparisons between modeled and observed sediment transport and depositional data.
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CSDMS 2014 annual meeting poster Xuan Yu

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Parameter and model uncertainty analysis of a physics-based hydrologic model: a comparative study of GLUE and Gaussian process emulator=
Xuan Yu, Pennsylvania State University University Park Pennsylvania, United States. xuanyupsu@gmail.comChristopher Duffy, Pennsylvania State University University Park Pennsylvania, United States. cxd11@psu.eduMurali Haran, Pennsylvania State University University Park Pennsylvania, United States. muh10@psu.edu
Abstract:
Quantification of uncertainty of environmental models plays an important role in the decision making process. The most popular method GLUE (Generalized Likelihood Uncertainty Estimation) has been argued for the computationally inefficiency due to the emerging of complex models. Recently, the Bayesian approach using Gaussian process (GP) emulator has been attracted much attention in the uncertainty analysis of computationally expensive models. It would be useful to compare the difference of this two methods in the uncertainty analysis of a physics-based hydrologic model. We evaluate the difference of GLUE and GP emulator in the assessment of parameter uncertainty of a physics-based integrated hydrologic model (Penn State Integrated Model: PIHM). PIHM integrates the hydrological processes including interception, throughfall, infiltration, recharge, evapotranspiration, overland flow, groundwater flow, and channel routing, in a fully coupled scheme. The tradition parameter estimation focuses only on the model performance at streamflow, which may cause significant uncertainty of parameter in other intermediate predicted variables (groundwater table, soil moisture, etc.). We demonstrate the uncertainty at each process to investigate the uncertainty transfer in the integrated framework of PIHM. This study considers the comparison between GLUE and GP emulator uncertainty analysis at a catchment at central PA: Shale Hills, where hydrologic processes are monitored, including intermediate variables of rainfall-runoff processes. The GLUE method attempts to evaluate the total uncertainty from model structure, parameter, and input data through a large sample of model simulation. Whereas, the GP emulator starts with designed samples of model runs, and allows inferring the values of the model output at untried points. The uncertainty disentanglement between model structure, parameter, and hydrologic processes suggests that ignoring intermediate variable uncertainty will lead to unrealistic model simulations.
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CSDMS 2014 annual meeting poster Ya Ping Wang

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Water and sediment discharge into the sea from Yangtze River: an improving measurement=
Ya Ping Wang, Nanjing University Najing , China. ypwang@nju.edu.cnJames T. Liu, National Sun Yat-sen University , China.Shu Gao, Nanjing University , China. 
Abstract:
One third of the world population lives in the coastal zone whose natural environment and ecosystems are directly impacted by the freshwater and sediment discharged by the rivers. Yet, the conventional method to estimate the river discharges is based on the record of the gauging station located closest to the river mouth, which could be hundreds of kilometers away; such a method is insufficient to produce accurate values. Here we present in-situ yearlong observations of the water and sediment discharges through a cross-section near the mouth of the Changjiang (Yangtze River). This data was first compared to the data obtained from the nearest river gauging station at Datong, and then used to derive two methods to accurately estimate the water and sediment discharges of the entire drainage basin.
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CSDMS 2014 annual meeting poster Yu Zhang

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Fully-Coupled Hydrologic-Morphologic Processes for Modeling Landscape Evolution=
YU Zhang, The Pennsylvania State University University Park Pennsylvania, United States. YZZ130@PSU.EDURudy Slingerland, The Pennsylvania State University University Park Pennsylvania, United States. rxs15@psu.eduChristopher Duffy, The Pennsylvania State University University Park Pennsylvania, United States. cxd11@psu.edu
Abstract:
Investigating the impacts of properties, distribution and evolution of regolith on river channel, fluid pathways, flow rate and sediment transport is essential to resource management and restoration efforts. Besides field experiment studies, numerical simulation is also an efficient way to explore the relationship between the hydrological and morphological processes. Recent studies focus more on the interaction of physical processes that govern the surface hydrodynamics and morphodynamics. However, the fluid flow on the subsurface layer plays an important role on landscape evolution as well.
This study takes into account of the water exchange between surface and subsurface and water flow within subsurface and fully couples them into a 3D hydrologic-morphodynamic model (LE-PIHM) for regolith formation and landscape evolution by using finite volume strategy. Two scenarios, coupling subsurface flow and no subsurface flow, are applied in a synthetic experiment. A comparison of the simulation results in the two scenarios at steady state indicates that subsurface flow has significant influences on the distribution of regolith, steepness of hillslope, network density, drainage area and water balance.
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CSDMS 2014 annual meeting poster Zhixuan Feng

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2014</font>
=Modeling sediment-related loading, transport, and inactivation of fecal indicator bacteria at a nonpoint source beach=
Zhixuan Feng, University of Miami Miami Florida, United States. zfeng@rsmas.miami.eduAd Reniers, University of Miami Miami Florida, United States.Brian Haus, University of Miami Miami Florida, United States.Helena Solo-Gabriele, University of Miami Coral Gables Florida, United States.
Abstract:
Enterococci are the U.S. Environmental Protection Agency (EPA) recommended fecal indicator bacteria for assessing recreational marine water quality. Traditional methods of enterococci analyses are time consuming, resulting in delays in issuing beach closures. Models can potentially circumvent these delays by forecasting times when beaches should be closed. The objective of this study is to develop an innovative coupled microbe-hydrodynamic-morphological model. The unique feature of this model is its capability of simulating the release of microbes attached to coastal beach sands as a result of combined wave and tidal forcing. A nearshore process model (XBeach) was coupled with a microbe transport-decay equation. This equation included source functions that accounted for microbial release from mobilized sand, groundwater flow, entrainment through pore water diffusion, rainfall-runoff loading, and a fate function that accounted for solar inactivation effects. The model successfully simulated observed spatial and temporal patterns of enterococci in the beach water, including the reproduction of diel and tidal fluctuations and the rapid decrease of enterococci levels from the waterline to offshore. Primary processes for enterococci loading to the water column included wave-induced sediment resuspension and tidal washing for the entrainment of enterococci from the pore water in the intertidal zone. Diffusion was the major mechanism to transport enterococci from the intertidal zone to offshore. Sunlight inactivation was a key process to reduce enterococci levels during the day and to produce the diurnal cycles. Rainfall runoff was found to be an intermittent source of enterococci to beach water, whereas groundwater exchange was of secondary importance. Sensitivity analyses suggested that the processes and coefficients related to enterococci loading have quasi-linear characteristics, whereas model results of enterococci levels were sensitive to both diffusion and sunlight inactivation coefficients, showing high nonlinearity and spatial and temporal dependence.
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CSDMS 2015 annual meeting poster AlbertKettner

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2015</font>
=CSDMS Tools to Promote Visibility of Open-source Model Code=
Albert Kettner, Univ. of Colorado, INSTAAR, CSDMS, Colorado, United States. albert.kettner@gmail.comIrina Overeem, CSDMS, INSTAAR, University of Colorado, Colorado, United States.
Abstract:
CSDMS encourages and supports the effort of developers to provide their numerical models as truly open source codes. CSDMS uses GitHub as their software version control system to provide access for those who want to share their model source code regardless of whether a model is still in development or for stable versions. GitHub keeps track of current and historical versions of source code, it allows for easy download, makes code highly visible, and permits for easy contributions, even from parties that are not directly associated with the developers core team. All one needs to contribute code to GitHub is a Git client version on your computer. Not every developer may be familiar with GitHub, therefore developers can provide source code to CSDMS and the Integration Facility will maintain the GitHub repository. Additionally if developers want to learn more about Git and GITHub, CSDMS has provided Git/GitHub software bootcamps and clinics in the past and envisions to provide such in upcoming annual meetings as well.
CSDMS promotes open source code as it reduces redundancy; it guarantees re-use and it makes research more replicable. At the same time CSDMS strives to ensure that model developers receive recognition for their work, even when code is submitted but not (yet) described in a scientific journal. Therefore CSDMS was one of the first organizations to adopt the Digital Object Identifier (DOI) system for source code. For this, we collaborated with IEDA (Integrated Earth Data Applications, hosted at the Lamont-Doherty Earth Observatory of Columbia University). Now that this practice is becoming more commonplace, we have switched to using the DOI service of Zenodo (CERN) as it has an easy to use and integrated tool through GitHub.
With the help of a brief model description form on the CSMDS portal, the developers can provide basic model information and indicate under which software license the model source code is available. Licensing software ensures the developer that models once made freely available will continue to be available for the community, even if others are 'upgrading' your code. At the same time appropriate open-source licenses protect the development team. CSMDS advises which software licenses to use.
Finally, CSDMS promotes contributions of open source software by highlighting newly submitted models at the FrontPage of its website and through social media.
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CSDMS 2015 annual meeting poster AlejandroTejedor

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2015</font>
=A graph-theoretic approach to Studying Deltaic Systems: Quantifying Complexity and Self-Organization.=
Alejandro Tejedor, University of Minnesota, Minnesota, United States.alej.tejedor@gmail.comAnthony Longjas, University of Minnesota, Minnesota, United States.Ilya Zaliapin, University of Reno, Nevada, United States.Efi Foufoula-Georgiou, University of Minnesota, Minnesota, United States.
Abstract:
River deltas are intricate landscapes with complex channel networks that self-organize to deliver water, sediment, and nutrients from the apex to the delta top and eventually to the coastal zone. Most of the deltas are subject to anthropogenic and natural perturbations causing topological and dynamical changes in the delta structure and function. Conceptualizing a delta channel network as a directed graph where channels are modeled by edges and junctions by vertices, we present a quantitative framework based on spectral graph theory within which a systematic study of the topology and transport dynamics of river deltas can be performed. Specifically, this framework allows us, from algebraic computations, to depict structural features of the delta system such as sub-networks (from apex to shoreline outlets), and contributing and nourishing areas. We also introduce metrics of topologic and dynamic complexity and define a multidimensional complexity space where each delta projects. The aim is to decode in this space the information stored in the delta connectivity as imprinted by the morphodynamic processes (e.g., river, tide, waved dominated) and other physical parameters of the system (e.g. sediment cohesiveness).
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CSDMS 2015 annual meeting poster AnthonyLongjas

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2015</font>
=Vulnerability maps of deltas: quantifying how network connectivity modulates upstream change to the shoreline=
Anthony Longjas, University of Minnesota, Minnesota, United States. alongjas@umn.eduAlejandro Tejedor, University of Minnesota, Minnesota, Pennsylvania, United States.Ilya Zaliapin, University of Nevada, Nevada, United States.Efi Foufoula-Georgiou, University of Minnesota, Minnesota, United States.
Abstract:
The complex bifurcation and merging structure (called connectivity) of delta channel networks and the partitioning of fluxes at every junction determine the spatial flux distribution on the deltaic surface from the apex to the shoreline. Changes in any upstream part of the network will propagate downstream, and depending on the location of this change and the network connectivity, a particular perturbation will be attenuated to a different degree on its way to the shoreline. It is of interest to have a computationally efficient framework by which every channel in the delta network can be assigned a “vulnerability index” according to its potential to mitigate the propagation of the local change (e.g., a reduction of flux) to the shoreline. Here we present a framework for performing such an analysis by conceptualizing the network as a directed graph and using spectral graph theory to compute steady-state fluxes. We use the developed framework to construct vulnerability maps that quantify the relative change of sediment and water delivery to the shoreline outlets in response to possible perturbations in hundreds of upstream links. This enables us to evaluate which links (hotspots) and what management scenarios would most influence flux delivery to the outlets, paving the way for systematically examining how local or spatially distributed delta interventions can be studied within a systems approach for delta sustainability.
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