Model:CEM: Difference between revisions
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|Phone=919 681-5069 | |Phone=919 681-5069 | ||
|Fax=919 684-5833 | |Fax=919 684-5833 | ||
|First_name=Jordan | |||
|Last_name=Slott | |||
|Type_of_contact=Model developer | |||
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{{Model identity | {{Model identity | ||
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|One-line model description=Coastal evolution model | |One-line model description=Coastal evolution model | ||
|Extended model description=The Coastline Evolution Model (CEM) addresses predominately sandy, wave-dominated coastlines on time-scales ranging from years to millenia and on spatial scales ranging from kilometers to hundreds of kilometers. Shoreline evolution results from gradients in wave-driven alongshore sediment transport. At its most basic level, the model follows the standard 'one-line' modeling approach, where the cross-shore dimension is collapsed into a single data point. However, the model allows the plan-view shoreline to take on arbitrary local orientations, and even fold back upon itself, as complex shapes such as capes and spits form under some wave climates (distributions of wave influences from different approach angles). The model can also represent the geology underlying the sandy coastline and shoreface in a simplified manner and enables the simulation of coastline evolution when sediment supply from an eroding shoreface may be constrained. CEM also supports the simulation of human manipulations to coastline evolution through beach nourishment or hard structures. | |Extended model description=The Coastline Evolution Model (CEM) addresses predominately sandy, wave-dominated coastlines on time-scales ranging from years to millenia and on spatial scales ranging from kilometers to hundreds of kilometers. Shoreline evolution results from gradients in wave-driven alongshore sediment transport. At its most basic level, the model follows the standard 'one-line' modeling approach, where the cross-shore dimension is collapsed into a single data point. However, the model allows the plan-view shoreline to take on arbitrary local orientations, and even fold back upon itself, as complex shapes such as capes and spits form under some wave climates (distributions of wave influences from different approach angles). The model can also represent the geology underlying the sandy coastline and shoreface in a simplified manner and enables the simulation of coastline evolution when sediment supply from an eroding shoreface may be constrained. CEM also supports the simulation of human manipulations to coastline evolution through beach nourishment or hard structures. | ||
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|Last_name=Slott | |||
|Type_of_contact=Model developer | |||
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{{Model technical information | {{Model technical information | ||
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|Memory requirements=20 Mb | |Memory requirements=20 Mb | ||
|Typical run time=days | |Typical run time=days | ||
|First_name=Jordan | |||
|Last_name=Slott | |||
|Type_of_contact=Model developer | |||
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{{Input - Output description | {{Input - Output description | ||
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|If above answer is yes=Matlab | |If above answer is yes=Matlab | ||
|Other visualization software=Note: if using the JPEGs automatically generated, the answer to the visualization question is 'no.' | |Other visualization software=Note: if using the JPEGs automatically generated, the answer to the visualization question is 'no.' | ||
|First_name=Jordan | |||
|Last_name=Slott | |||
|Type_of_contact=Model developer | |||
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{{Process description model | {{Process description model | ||
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|Describe time scale and resolution constraints=Years to millenia. Typically, the model is run with timesteps on the order of a day. However, the assumptions that the shoreface progrades or erodes while maintaining its cross-shore shape prevents model results from being interpreted as meaningful over time scales shorter than years to decades. (Storm and post storm cross-shore shifting of sediment within the shoreface causes shoreline fluctuations on event timescales that are implicitly averaged out in this model.) | |Describe time scale and resolution constraints=Years to millenia. Typically, the model is run with timesteps on the order of a day. However, the assumptions that the shoreface progrades or erodes while maintaining its cross-shore shape prevents model results from being interpreted as meaningful over time scales shorter than years to decades. (Storm and post storm cross-shore shifting of sediment within the shoreface causes shoreline fluctuations on event timescales that are implicitly averaged out in this model.) | ||
|Describe any numerical limitations and issues=The model handles complex-shaped coastlines, such as cuspate-capes and spits. However, where the shoreline curvature becomes extreme (radius of curvature comparable to the cross-shore shoreface extent), as at the ends of spits, the assumptions of a locally rectilinear coordinate system break down, and sediment is conserved less rigorously locally. See Ashton and Murray (2006a) for details. | |Describe any numerical limitations and issues=The model handles complex-shaped coastlines, such as cuspate-capes and spits. However, where the shoreline curvature becomes extreme (radius of curvature comparable to the cross-shore shoreface extent), as at the ends of spits, the assumptions of a locally rectilinear coordinate system break down, and sediment is conserved less rigorously locally. See Ashton and Murray (2006a) for details. | ||
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|Last_name=Slott | |||
|Type_of_contact=Model developer | |||
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{{Model testing | {{Model testing | ||
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However, to date the model has been used chiefly for relatively abstract explorations of how coastline evolution works: how emergent coastline structures such as capes, spits, and alongshore sand waves form and interact; how heterogeneity in underlying geology affects coastline evolution; how scenarios of changing storm and wave climates would affect coastline change; and how human manipulations alter large-scale coastline change). Ashton and Murray (2006b) compared robust model predictions concerning the way local wave climates vary along a coastline with emergent structures (capes and flying spits) to hindcast wave climates along actual shorelines. As opposed to testing whether model parameters can be adjusted to reproduce observations in detail, testing a robust prediction like this, which does not depend on the formal details of the model ingredients, can falsify the hypothesis that the interactions in the model capture the basic aspects of the interactions that are important in the actual system (see Murray, 2003; 2007). | However, to date the model has been used chiefly for relatively abstract explorations of how coastline evolution works: how emergent coastline structures such as capes, spits, and alongshore sand waves form and interact; how heterogeneity in underlying geology affects coastline evolution; how scenarios of changing storm and wave climates would affect coastline change; and how human manipulations alter large-scale coastline change). Ashton and Murray (2006b) compared robust model predictions concerning the way local wave climates vary along a coastline with emergent structures (capes and flying spits) to hindcast wave climates along actual shorelines. As opposed to testing whether model parameters can be adjusted to reproduce observations in detail, testing a robust prediction like this, which does not depend on the formal details of the model ingredients, can falsify the hypothesis that the interactions in the model capture the basic aspects of the interactions that are important in the actual system (see Murray, 2003; 2007). | ||
|Describe ideal data for testing=See answer above and Ashton and Murray (2006a, b). Data sets spanning large spatial scales are most appropriate, and if model behaviors are going to be compared to shoreline change, long temporal scales are best (see ‘limitations’ above). | |Describe ideal data for testing=See answer above and Ashton and Murray (2006a, b). Data sets spanning large spatial scales are most appropriate, and if model behaviors are going to be compared to shoreline change, long temporal scales are best (see ‘limitations’ above). | ||
|First_name=Jordan | |||
|Last_name=Slott | |||
|Type_of_contact=Model developer | |||
}} | }} | ||
{{Users groups model | {{Users groups model | ||
|Do you have current or future plans for collaborating with other researchers?=Collaborations are underway within Duke University (an interdisciplinary project involving human shoreline manipulations) and Woods Hole Oceanographic Institution (where the model is being used to explore delta dynamics). Various collaborations involving researchers in the US and abroad are in various stages. | |Do you have current or future plans for collaborating with other researchers?=Collaborations are underway within Duke University (an interdisciplinary project involving human shoreline manipulations) and Woods Hole Oceanographic Institution (where the model is being used to explore delta dynamics). Various collaborations involving researchers in the US and abroad are in various stages. | ||
|First_name=Jordan | |||
|Last_name=Slott | |||
|Type_of_contact=Model developer | |||
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{{Documentation model | {{Documentation model | ||
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* Murray, A.B., 2003, Contrasting the goal, strategies, and predictions associated with simplified numerical models and detailed simulations, in Prediction in Geomorphology, Dick Iverson and Peter Wilcock Eds, Geophysical Monograph 135, American Geophysical Union, 151-165. | * Murray, A.B., 2003, Contrasting the goal, strategies, and predictions associated with simplified numerical models and detailed simulations, in Prediction in Geomorphology, Dick Iverson and Peter Wilcock Eds, Geophysical Monograph 135, American Geophysical Union, 151-165. | ||
|Manual model available=No | |Manual model available=No | ||
|First_name=Jordan | |||
|Last_name=Slott | |||
|Type_of_contact=Model developer | |||
}} | }} | ||
{{Additional comments model | {{Additional comments model | ||
|Comments=This entry, with the name 'Coastline Evolution Model' should replace the 'Murray model' currently listed. Thanks Albert! | |Comments=This entry, with the name 'Coastline Evolution Model' should replace the 'Murray model' currently listed. Thanks Albert! | ||
|First_name=Jordan | |||
|Last_name=Slott | |||
|Type_of_contact=Model developer | |||
}} | }} | ||
{{Infobox Model | {{Infobox Model |
Revision as of 16:05, 25 November 2009
Contact
Name | A. Brad Murray |
Type of contact | Project manager |
Institute / Organization | Duke University |
Postal address 1 | Box 90230 |
Postal address 2 | |
Town / City | Durham |
Postal code | 27708-0230 |
State | North Carolina |
Country | USA"USA" is not in the list (Afghanistan, Albania, Algeria, Andorra, Angola, Antigua and Barbuda, Argentina, Armenia, Australia, Austria, ...) of allowed values for the "Country" property. |
Email address | abmurray@duke.edu |
Phone | 919 681-5069 |
Fax | 919 684-5833 |
CEM
Metadata
Summary
Technical specs
In/Output
Process
Testing
Other
IntroductionNOTE: This page is still under development. Some information may be incorrect. When we believe everything is correct, we'll remove this message. Coastline Evolution Model: IntroductionThis site hosts the source code for the Coastline Evolution Model (CEM) from Duke University. To find out more technical details of this model, please visit the Model:Test_CEM#Metadata page. This purpose of the instructions on this page are to explain how to download, compile, and use the model. Please keep in mind this is an open-source project, not shrink-wrapped software. So it may require a bit of effort to get running on your own system. The source code is very-well documented however, and we'd encourage you to extend it for your own purposes. The source code is licensed under the Berkeley Standard Distribution (BSD) license. Supported Systems & RequirementsCurrently, the source code has only been run on Linux CentOS (which is a variation of RedHat Linux). It has also been successfully used on Mac OSX and Solaris, but the Makefiles will need slight tweaks on those systems. We'd appreciate any help getting the model to run on systems other than Linux! The model code is written in C and requires the GNU Compiler Collection (GCC), preferably under version 4.0.2 or greater. It has also been run under GCC v2.9.6. Please do not use the GCC v3.x.x compiler series; we have run into issues with them. The model code requires two libraries to be installed on your system:
You may need to tweak the Makefile to compile if you have these two libraries installed in a non-standard location; contact us for help. Download needs to get the Source CodeTo download the source code, you must use Subversion (svn), which you can get at http://subversion.tigris.org/. For help on how to use Subversion, an excellent manual is available online at http://svnbook.red-bean.com/ Source Code CEMCEM is a stand-alone subroutine. To browse the repository, point your browser to: http://csdms.colorado.edu/viewvc/?root=cem Command-Line AccessIf you plan to make changes, use this command to check out the code as yourself using HTTPS: # Project members authenticate over HTTPS to allow committing changes.
svn checkout https://csdms.colorado.edu/svn/cem/
When prompted, enter your CSDMS Subversion password. Non-members may only check out a read-only working copy of the project source. To obtain a CSDMS Subversion account or to become a member of this project, please email csdms@colorado.edu.
Source-Code SnapshotsSource-code snapshots are available via ftp at: The latest version: Compiling the Source CodeOnce you have downloaded the source code, you can compile it using the UNIX/Linux 'make' utility (which should come standard with your Operating System). It is probably worthwhile to edit the Makefile in the cem/ and cem/tools/ directories to set the options you want. There are further instructions there. To compile from the cem/ directory, simply enter the 'make' command. It compiles the model into an executable named 'cem'. It also compiles the tools/ subdirectory. Running the CEM ModelThe CEM model is a command-line driven program. It has no GUI (Graphical User Interface). It takes several inputs:
It generates several outputs:
Once you have generated the configuration file, the initial shoreline, and the set of wave forcings (described below), you can run the model on the command-line as follows: % cem --config=<path to config file>/config.xml Note that the 'cem' executable must be in your path, and <path to config file> is the directory in which the XML configuration file is located. The XML-based Configuration FileA text-based XML-formatted file sets configuration options for CEM. You can find an example in the xml/ subdirectory. Please use that example config.xml for your own purposes. The configuration options are relatively straight forward with brief explanations below.
Creating an Initial Shoreline (SPX) FileThere is a utility program in the tools/ directory, called 'spxcreate' to create an initial shoreline. This utility creates model shorelines that are initially straight or have small initial perturbations. The utility works off a set number of predefined shorelines; you have the ability to override any individual attribute of the initial shoreline. For example, % spxcreate "Rough Beach 100m" will create an initially straight shoreline with small perturbations that is 150 cells alongshore, 100 cells cross-shore, where each cell is 100 m on each side. If you want to make an initial shoreline with an alongshore length of 300 cells instead, you can do something like % spxcreate "Rough Beach 100m" ALONG=300 Please see the source code (tools/spxcreate.c) for more documentation. Typically, cells in the shoreline have widths of either 100 m or 1000 m. Creating a Wave Forcings (WVX) FileThere is a utility program in the tools/ directory, called 'wvxcreate' to create an initial shoreline. This utility creates waves according to two parameters: the proportion of waves approaching from high angles and the proportion of the waves approach from the left (looking off-shore). For example, % wvxcreate -n 5000 -d 0.60 -h 0.55 -w 1.7 -f waves.wvx will create a file named 'waves.wvx' that contains 5000 waves. Each wave has a height of 1.7m and 60% of the wave influences approach from the left (looking off-shore) and 55% of the wave influences approach from high-angle. Note that you must generate enough waves for your simulation. The number of waves is simply the number of timesteps of your simulation divided by the number of timesteps per wave as set in your config.xml file. Processing the OutputThe CEM model lets you generate both shoreline (SPX) files and picture (JPEG) files at any point during the simulation. If you wish to generate a text file of the positions of the beach (the dividing line between the ocean and land), you may use the 'spxposition' utility located in the tools/ directory. You can then import this text file into other programs (e.g. MATLAB). The usages of the 'spxposition' utility is simple: % spxposition <spx file> IssuesHelpInput FilesOutput FilesDownloadSource |