nyuuzyou/wikis huggingface dataset:
CSDMS 2013 annual meeting poster Carl Friedrichs

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2013</font>
=Combining Observations and Numerical Model Results to Improve Estimates of Hypoxic Volume Within the Chesapeake Bay=
Carl Friedrichs, Virginia Institute of Marine Science Gloucester Point Virginia, United States. cfried@vims.eduAaron Bever, Delta Modeling Associates, Inc. San Francisco California, USA. aaron@deltamodeling.comMarjy Friedrichs, Virginia Institute of Marine Science Gloucester Point Virginia, USA. marjy@vims.eduMalcolm Scully, Woods Hole Oceanographic Institution Woods Hole Massachusetts, United States. mscully@whoi.edu
Abstract:
The overall size of the Chesapeake Bay “dead zone” is quantified by the Bay’s hypoxic volume (HV), i.e., the volume of water with dissolved oxygen (DO) less than 2 mg/L. In order to improve estimates of HV, DO was subsampled from the output of three dimensional model hindcasts at times/locations matching the set of 2004-2005 stations monitored by the Chesapeake Bay Program. The resulting station profiles were then input into an interpolation program to produce Bay-wide estimates of HV in a manner consistent with non-synoptic, cruise-based estimates. Interpolations of the same stations sampled synoptically as well as multiple other combinations of station profiles were examined in order to quantify uncertainties associated with interpolating HV from observed profiles. The potential uncertainty in summer HV estimates resulting from profiles being collected over two weeks rather than synoptically, averaged ~5 km^3. This is larger than that due to sampling at discrete stations and interpolating/extrapolating to the entire Bay (2.4 km^3 ). As a result, sampling fewer, selected stations over a shorter time period is likely to reduce uncertainties associated with interpolating HV from observed profiles. A function was also derived, that, when applied to a subset of 13 stations, significantly improved estimates of HV. Finally, multiple metrics for quantifying Bay wide hypoxia were examined, and cumulative hypoxic volume was determined to be particularly useful, as a result of its insensitivity to temporal errors and climate change. A final product of this analysis is a nearly three-decade time series of improved estimates of HV for Chesapeake Bay. (Submitted March 2013 to Journal of Geophysical Research. For a pdf pre-print contact Carl Friedrichs at cfried@vims.edu .)
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CSDMS 2013 annual meeting poster Chris Jenkins

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2013</font>
=Globally extensive, Subgrid scale, Seafloor Drag (z0) for Input to Models=
Chris Jenkins, instaar Boulder Colorado, United States. chris.jenkins@colorado.eduEnda O'Dea, UK Met Office Exeter NO STATE, United Kingdom. enda.odea@metoffice.gov.uk
Abstract:
By using spatially-varying estimates of seabed bottom drag (z0) the performance of ocean current and tide numerical models may be improved. To an extent, the seabed database dbSEABED is able to supply these values from data on the seabed materials and features. But then adjustments for varying dynamic (wave, flow) conditions are also required. So the data and model must work closely together. We developed methods for calculating inputs of z0 for circulation models in this way. Preliminary outputs from this new globally capable facility are demonstrated for the NW European Shelf region (NWES). 
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CSDMS 2013 annual meeting poster Dan Ames

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2013</font>
=HydroDesktop and the CUAHSI Hydrologic Information System=
Dan Ames, Brigham Young University Provo Utah, United States. dan.ames@byu.edu
Abstract:
This presentation or poster will discuss the latest developments of the CUAHSI Hydrologic Information System including 1) the new open source server components built using PHP and MySQL specifically to support citizen science; and 2) the desktop application HydroDesktop with its extensions for search and discovery of data on the 100 servers of the CUAHSI data network. The presentation or poster will include a discussion of the potential integration of HIS data sources in CSDMS modeling efforts and potential for integration of the CSDMS modeling architecture with the HydroDesktop client application. 
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CSDMS 2013 annual meeting poster Elchin Jafarov

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2013</font>
=The effect of snow: How to better model ground surface temperatures=
Elchin Jafarov, NSIDC Boulder Colorado, United States. elchin.jafarov@gmail.com
Abstract:
We present a method that reconstructs daily snow thermal conductivities using air and ground temperature measurements. The method recovers the daily snow thermal conductivities over the entire snow season. By using reconstructed snow conductivities we can improve modeling of ground surface temperatures. Simulation of the ground surface temperatures by using changing in time snow thermal conductivities could potentially reduce ground temperature modeling uncertainty.
The developed method was applied to four permafrost observation stations in Alaska. Reconstructed snow thermal conductivity time series for the interior stations in Alaska revealed low conductivity values that reach their maximum towards the end of the snow season, while the northern stations showed high conductivity values that reach their maximum towards the middle of the snow season. The differences in snow conductivities between interior and northern stations are most likely due to wind compaction which is more pronounced in the Northern Arctic lowlands of Alaska.
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CSDMS 2013 annual meeting poster Elizabeth Olhsson

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2013</font>
=The Dynamic Watershed and Coastal Ocean: Predicting Biogeochemical Linkages and Variability over Decadal Time Scales=
Elizabeth Olhsson, University of California Berkeley California, United States. lolhsson@berkeley.edu
Abstract:
The west coast of North America is the setting for one of the world’s largest coastal upwelling regions. Large rivers drain from North America into the northern eastern Pacific Ocean, delivering large loads of sediments, as well as nutrients, organic matter and organisms. The Eel River discharges into the North Pacific just north of Cape Mendocino in Northern California. Its annual discharge (~200 m3/s) is about 1% that of the Mississippi, but its sediment yield (15 million tons/yr) is the highest for its drainage area (9500 km2) in the entire continental US. This strongly seasonal signal, generated largely by winter storm events that flush sediment and detritus into the river and down to the sea, generates dramatic nutrient pulses that may play a role in the timing and magnitude of offshore phytoplankton blooms. Understanding how the interannual variability of weather, moderated by slower trends in climate, affects these pulses, which in turn may alter offshore nutrient availability, is something we hope to explore through a detailed modeling framework. In our coupled modeling framework, the watershed is currently represented by the lumped empirical watershed model HydroTrend for its ability to generate high-frequency water and sediment time series in relatively unstudied basins. The atmosphere is represented by the NCEP North American Regional Reanalysis, a model and data assimilation tool. Eventually, we hope to represent the atmosphere with the Community Earth System Model, a powerful tool for studying climate change projections, which will let us talk about possible future impacts of climate change on coastal productivity. The ocean is represented with the Regional Ocean Modeling System, a powerful and very modular, physically distributed model that can efficiently solve fine-scale resolution grids. The coastal biology will be handled by modification of an iron-limited nutrient-phytoplankton-zooplankton-detritus model.
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CSDMS 2013 annual meeting poster France Floch

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2013</font>
=2D modelisation of non-hydrostatic internal waves on idealised embankment=
France Floc'h, IUEM Plouzane , France. france.floch@univ-brest.frAnnick Pichon, SHOM Brest , France. pichon@shom.fr
Abstract:
An Isopycnic Coordinate Ocean Model is used to represent the propagation of internal tides in the Bay of Biscay and their desintegration into solitons. To model important vertical variability of the thermocline, such as solitons, a non-hydrostatic model is necessary. In this study, we test the possibility of integrated non-hydrostatics terms under weakly nonlinear and nonhydrostatic approximation. Non-hydrostatic terms derived with this assumption, are directly added to the hydrostatic equations. We then address numerical problems : mesh size limitation responsible for numerical dispersion, numerical instabilities. After having investigated these problems analytically and tested the limitation, a stable method is proposed. Results for a 2D idealised configuration of the Bay of Biscay is described : the model is forced by the semi-diurnal tidal wave M2, two layers of different density are considered. The internal waves is desintegrated into solitons after few tidal periods.
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CSDMS 2013 annual meeting poster Greg Tucker

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2013</font>
=A Generic "Gridding Engine" for 2D Modeling of Earth-Surface Dynamics=
Greg Tucker, CIRES Boulder Colorado, United States. gtucker@colorado.eduNicole Gasparini, Tulane Univ New Orleans Louisiana, United States.Erkan Istanbulluoglu, Univ Washington Seattle Washington, United States.Eric Hutton, CSDMS Boulder Colorado, United States.Dan Hobley, Univ Colorado Boulder Colorado, United States.
Abstract:
This presentation addresses an important limitation to scientific productivity in fields that rely on computational modeling of landscape processes. Landscape models compute flows of mass, such as water, sediment, glacial ice, volcanic material, or landslide debris, across a gridded terrain surface. Science and engineering applications of these models range from short-term flood forecasting to long-term landform evolution. At present, software development behind these models is highly compartmentalized and idiosyncratic, despite the strong similarity in core algorithms and data structures between otherwise diverse models.
We report progress on a proof-of-concept study in which an existing landscape model code is adapted and enhanced to provide a set of independent, interoperable components (written initially in C++). These include: (1) a gridding engine to handle both regular and unstructured meshes, (2) an interface for space-time rainfall input, (3) a surface hydrology component, (4) an erosion-deposition component, (5) a vegetation component and (6) a simulation driver. The components can communicate with each other in one of two ways: using a simple C++ driver script, or using the Community Surface Dynamics Modeling System (CSDMS) Model Coupling Framework. 
A central element is the gridding engine, which provides the ability to rapidly instantiate and configure a 2D simulation grid. Initially, the grid is an unstructured Delaunay/Voronoi mesh. Because the internal representation of geometry and topology is quite generic—consisting of nodes (cells), directed edges, polygon faces, etc.—the software can be enhanced to provide other grid formats, such as a simple raster or a quad-tree representation. The gridding engine also provides basic capabilities for finite-volume numerics, such as calculation of scalar gradients between pairs of neighboring cells, and calculation of flux divergence within cells. 
Our hope is that these interoperable and interchangeable components with simple, standardized interfaces, will transform the nature and speed of progress in the landscape sciences by allowing scientist-programmers to focus on the processes of interest rather than on the underlying software infrastructure.
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CSDMS 2013 annual meeting poster Irina Overeem

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2013</font>
=Modeling of Waves and Storm Surge along the Arctic Coast of Alaska=
Irina Overeem, University of Colorado Boulder Colorado, United States. irina.overeem@colorado.eduKaty Barnhart, University of Colorado Boulder Colorado, United States. katy.barnhart@colorado.eduRobert Anderson, University of Colorado Boulder Colorado, United States. r.s.anderson@colorado.edu
Abstract:
Arctic coasts have been impacted by rapid environmental change over the last 30 years. Warming air and water temperatures and the increased duration of the open water season, correlate with increases in the rate of already rapid erosion of ice-rich bluffs along the Beaufort Sea coast. To investigate longer-term changes in near-shore wave dynamics and storm surge set up as a result of sea-ice retreat, we coupled two simple modules. 
Following Dean and Dalrymple (1991), we model wind-driven setup as a function of wind speed and direction, azimuth relative to the shore-normal, fetch and bathymetry. The wave module calculates the wave field for fetch-limited waves in shallow water based on the Shore Protection Manual (1984). For a given wind speed, dynamic water depth and fetch, we predict the significant wave height and wave period. Both modules require fetch as a controlling parameter. Sea-ice influenced coasts, are unique in that fetch is spatially variable due to the geometry of the shoreline and temporally variable as the location of the sea ice edge moves through the sea ice free season. We determine the distance to the sea ice edge using daily Nimbus 7-SMMR/SSM/I and DMSP SSMI Passive Microwave Sea Ice Concentration data. The sea ice edge is defined at a threshold sea ice concentration of 15%. We find a good match between the model predictions and our observed records of meteorological conditions and nearshore water level and waves along the Beaufort Coast in the summers of 2009 and 2010.
Over the period 1979-2012, fetch has increased significantly. In our study area near Drew Point, Alaska, the open water season itself lengthened from ~45 days to ~90 days. In the 1980’s and early 1990’s wave dynamics were fetch-limited during a significant period of the open water season. More recently, the distance from the coast to the sea ice edge shifts extremely rapidly (often 100’s of km over 1-2 weeks); fetch therefore only minimally influences wave dynamics as offshore distance exceeds the 140 km threshold over most of the open water season. Wave heights and surge set-up events on average have not changed in magnitude significantly, but storm surge set up events have increased in frequency.
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CSDMS 2013 annual meeting poster Jeremy Kerr

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2013</font>
=A 3-D cellular depositional model of platform evolution delivered at fine scale=
Jeremy Kerr, Nova Southeastern University Oceanographic Center Dania Florida, United States. jk908@nova.eduSamuel Purkis, Nova Southeastern University Oceanographic Center Dania Florida, United States. purkis@nova.edu
Abstract:
Satellite and field observations find modern carbonate depositional systems to be self-organized, yet the processes generating such behavior are not fully understood. A 3-D forward model of carbonate reef growth rooted in cellular automata is developed to simulate the evolution of self-organized geometry through time. Carbonate landscapes are generated over spatial extents of several kilometers through time scales of millennia at meter-scale resolution. Classes in the model include carbonate factories (e.g., branching and massive coral communities, algal communities) and sinks (e.g., unconsolidated sand). Environmental factors include relative sea level and light intensity, and ecological controls are based on life history traits for the biological facies. Ecological processes within the model include mortality and colonization rates for biological classes, transition probabilities between facies, and rates of vertical accretion. The algorithm results in a self-organized landscape that emulates those observed in nature, such as rims and reticulate structures. Visualizations can be produced by accessing topographic and facies maps generated at each time step. This project’s goals are 1) to investigate which configurations of environmental parameters result in specific spatial motifs, 2) examine the effects of environmental perturbations on reef construction, and 3) understand the importance of biological and physical regimes on the generation of geomorphological features.
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CSDMS 2013 annual meeting poster Jianwei Han

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2013</font>
=Exploring the mechanisms that control valley spacing in higher order fluvial channels with the CHILD Model=
Jianwei Han, Tulane University New Orleans Louisiana, United States. jhan@tulane.eduNicole Gasparini, Tulane University New Orleans Louisiana, United States. ngaspari@tulane.edu
Abstract:
Previous studies have found that the ratio between valley spacing and mountain range width is relatively constant across the globe, but the processes responsible for its uniformity are not well understood. To determine the reasons for this uniform ratio, we firstly need to explore why valleys are evenly distributed in a mountain range, and what factors can impact valley spacing. Recent research has found that the critical length between hillslope and fluvial processes is an important control on the valley spacing of first order fluvial channels. In this study, we use the CHILD landscape evolution model to explore how the critical length affects valley spacing in higher order fluvial channels, and we use these results to help explain the narrow range of observations in the valley spacing ratio. We find that valley spacing has a linear relationship with critical length in higher order channels and, for a given order channel, the ratio between valley spacing and critical length is relatively constant. This relationship demonstrates that the competition between hillslope and fluvial processes influences the distribution of higher order channels across the landscape. However, we also find that valley spacing is influenced by model initial conditions and variability across the landscape, such as orographic precipitation patterns. Moreover, for a fixed domain in our model, although the critical length may vary, the ratio between the valley spacing of trunk channels and mountain width remains in the range observed in real landscapes. The reason for this is that the order of trunk channels varies with the critical length. Therefore, for a given domain size (or mountain range width), a larger critical length can produce lower order trunk channels but with the same spacing value as higher order trunk channels with a smaller critical length. This may be one of the reasons why the spacing ratio is relatively constant across diverse natural settings.
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CSDMS 2013 annual meeting poster Jorge Lorenzo Trueba

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during CSDMS annual meeting 2013</font>
=A simple morphodynamic model of coastal barrier response to rising sea level=
Jorge Lorenzo Trueba, Woods Hole Oceanographic Institution Woods Hole Massachusetts, United States. jorge@whoi.edu
Abstract:
Low-lying coastal barriers face an uncertain future over the next century, with many projections suggesting end-of-century rates of sea-level rise as high as 1 cm/yr. The hazards associated with this passive inundation can be reasonably estimated using state-of-the-art tools. However, the coast is not a bathtub - increased sea levels enhance the ability for waves to reorganize the coast, typically resulting in increased shoreline retreat by moving sediment either offshore into deeper waters or onshore by overwashing the existing coast. 
Although many models of coastal change have been developed, the majority are either highly calibrated and intended to operate at the temporal scales of engineering projects (< ~5 years), offering little possibility of forecasting never-seen behaviors such as barrier drowning, or long-term geologic models, which typically assume that the coast maintains an ‘equilibrium’ configuration that moves with sea level. We aim at bridging the gap between these approaches by constructing a simple model that focuses on dynamical coupling of two primary barrier components: the marine domain represented by the active shoreface, which is constantly affected by transport and reworking by waves, and the backbarrier system, where the infrequent process of overwash controls landward mass fluxes. The model demonstrates that coastal barriers can respond to an accelerated sea-level rise in complex, less predictable manners than suggested by existing conceptual and long-term numerical models. Model behaviors under constant sea-level rise reveal two potential modes of barrier failure: ‘height drowning’, which occurs when overwash fluxes are insufficient to maintain the landward migration rate required to keep in pace with sea-level rise; and ‘width drowning’, which occurs when the shoreface response is insufficient to maintain the barrier geometry during landward migration. We also identify a mode of discontinuous barrier retreat, where barriers can experience punctuated intervals of rapid rollover and shoreline stability, even with constant rates of sea-level rise. We explore the sensitivity of these modes to external and internal variables, including sea-level rise rate, maximum overwash rate, shoreface response rate, and inland topography.
* Please acknowledge the original contributors when you are using this material. If there are any copyright issues, please let us know and we will respond as soon as possible.