Model:Chi analysis tools

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Chi analysis tools

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Summary Contact Technical specs In/Output Process Testing Other Component info Also known as Channel segment finder Model type Single Model part of larger framework Note on status model Date note status model Incorporated models or components: Spatial dimensions 1.5D Spatial extent Regional-Scale, Landscape-Scale, Watershed-Scale Model domain Terrestrial One-line model description Tool for examining channel profiles in chi-elevation space using the integral method of channel analysis Extended model description This tool is used for examining bedrock channels. The tool is based on the assumption that the stream power incision model (SPIM) adequately describes channel incision. Channels profiles are converted to chi-elevation space, where chi is a transformed longitudinal coordinate that takes drainage area into account. The tool uses a variety of statistical tests to extract the most likely series of segments with distinct steepness in chi-elevation space. It also performs statistical tests to determine the best fit m/n ratio, where m is an area (A) exponent and n is a slope (S) exponent in the SPIM with E = K A^m S^n, where E is an erosion rate and K is an 'erodibility'. Keywords: geomorphology, bedrock channel erosion, topographic analysis, Name Simon Mudd Type of contact Model developer Institute / Organization University of Edinburgh Postal address 1 School of GeoSciences Postal address 2 Drummond Street Town / City Edinburgh Postal code EH8 9XP State NO STATE Country United Kingdom Email address simon.m.mudd@ed.ac.uk Phone +44 (0) 131 650 2535 Fax Name David Milodowski Type of contact Model developer Institute / Organization University of Edinburgh Postal address 1 School of GeoSciences Postal address 2 Drummond Street Town / City Edinburgh Postal code EH8 9XP State NO STATE Country United Kingdom Email address Phone Fax Name Stuart Grieve Type of contact Model developer Institute / Organization University of Edinburgh Postal address 1 School of GeoSciences Postal address 2 Drummond Street Town / City Edinburgh Postal code EH8 9XP State NO STATE Country United Kingdom Email address Phone Fax Name Declan Valters Type of contact Model developer Institute / Organization University of Edinburgh Postal address 1 School of GeoSciences Postal address 2 Drummond Street Town / City Edinburgh Postal code EH8 9XP State NO STATE Country United Kingdom Email address Phone Fax Supported platforms Unix, Linux Other platform Programming language C++, Python Other program language Code optimized Single Processor Multiple processors implemented Nr of distributed processors Nr of shared processors Start year development 2012 Does model development still take place? Yes If above answer is no, provide end year model development Code development status When did you indicate the 'code development status'? Model availability As code Source code availability (Or provide future intension) Through CSDMS repository Source web address Source csdms web address https://github.com/csdms-contrib/chi_analysis_tools Program license type GPL v2 Program license type other Memory requirements Depends on the size of your DEM Typical run time A few minutes to several days depending on parameters and DEM size Describe input parameters The input is a 'channel file' and a 'driver file'. The channel file contains data on channel profiles within a channel network composed of a main stem and tributaries flowing into that main stem (that is, there are no tributaries of tributaries). The driver file contains parameters for the model run. The format of these files is described in the documentation that accompanies the model source code. Input format ASCII Other input format Describe output parameters The outputs are i) For chi_m_over_n_analysis.exe, a *.movern file that contains information about the goodness of fit of channel profiles to a series of linear segments as a function of the m/n ratio: this file is used to determine the best fit m/n ratio of a channel network. ii) For chi_get_profiles.exe, a series of *.tree files which contain information about the best fit channel segments in chi-elevation space. This data can be used to infer erosion rates, tectonics, or variations in erodibility. Output format ASCII Other output format Pre-processing software needed? Yes Describe pre-processing software Channel profile data must be prepared to meed the specifications of the *.chan file. The format of this file is described in the documentation provided with the source code. Post-processing software needed? No Describe post-processing software Visualization software needed? No If above answer is yes Other visualization software Describe processes represented by the model The module performs topographic analysis but the analysis is based on the assumption that the stream power incision model is a good approximation for channel incision. Describe key physical parameters and equations Topographic analysis so no physical parameters as such. The main parameters fro the module are: 1) sigma: the uncertainty (in metres, or meters for you yanks), of the topographic data. 2) The target nodes: These are the number of nodes you wish to use in each subset of the channel. For details see associated documentation. This should vary between 60-140. The module partitions data and the number of partitions is a highly nonlinear function of the number of nodes so target node values of >150 will lead to compute times of many months - forever. 3) The minimum segment length: The shortest contiguous number of nodes the user is willing to consider for statistical analysis (in testing, 8-20 performed reasonably well). If you chose 2 you will be performing linear analysis on segments with 2 data points which is clearly nonsense. 4) Mean skip: See associated documentation, but the module uses a Monte Carlo sampling regime which skips nodes, analyses a subset of data, and then performs this skipping and analysis routine over a number of iterations. For SRTM and ASTER data this should be 1-2. For 10m data it can be 1-10, and for LiDAR data you could skip up to 100 nodes. Note that because of the iterative processes you will need to increase the number of iterations as you increase the skip value if you are to sample all of the data. Describe length scale and resolution constraints With reasonable parameter values channel networks with individual channel of ~1000 nodes will take a few to 10s of minutes to analyse. The longer the channel network, the longer the analysis. Describe time scale and resolution constraints Topographic analysis so no time scale constraints. Describe any numerical limitations and issues See documentation. The major limitation is computational time. This can be alleviated with sensible selection of module parameters. See documentation for guidance. Describe available calibration data sets Topographic analysis: no calibration required. Upload calibration data sets if available: Describe available test data sets There are 3 datasets within this repository. One from Southwest Pennsylvania, one from the Apennines in Italy, and one from a CHILD model run. Datasets are the same as those run with the associated manuscript (http://www.geos.ed.ac.uk/homes/smudd/Muddetal_JGRsubmit.pdf) so users can compare results with figures from the manuscript. Upload test data sets if available: Describe ideal data for testing Any bedrock channel profile. Module is intended for use on topographic data. Do you have current or future plans for collaborating with other researchers? Yes. Is there a manual available? Yes Upload manual if available: Media:Chi analysis movern and profiles.pdf, Media:Chi analysis getting channel.pdf Model website if any Model forum / discussion board Comments This part will be filled out by CSDMS staff OpenMI compliant No but possible BMI compliant No but possible WMT component No but possible PyMT component Is this a data component Can be coupled with:

Model info Authors Simon Mudd Milodowski, Grieve, Valters Source code View in CSDMS GitHub repository Model citations Nr. of publications: 1 Total citations: 144 h-index: 1 m-quotient: 0.1 QR-code Link to this page Other models by author Chi analysis tools Marsh column model

Introduction

This code has been developed by the University of Edinburgh Land Surface Dynamics group to analyse channel longitudinal profiles using the integral method of channel analysis. The integral method is a means of comparing the relative steepness of channel profiles, normalized for drainage area. It is similar to, but has some advantages over, traditional slope area analysis. See Perron and Royden (2013) for more details on the integral method.

This particular code not only transforms channels using the integral method, but it also uses statistical techniques to find the most likely series of channel segments with distinct steepness and the most likely m/n ratio. The details of these algorithms can be found in Mudd et al. (submitted manuscript) which is available here: http://www.geos.ed.ac.uk/homes/smudd/Muddetal_JGRsubmit.pdf.

The code consists of objects that contain topographic data and their member functions, and driver programs perform the analyses. Full documentation is available under the ‘other’ tab in the wiki.

Reference: Perron, J.T. and L. Royden (2013). An integral approach to bedrock river profile analysis. Earth Surface Processes and Landforms, 38, 570-576, doi:10.1002/esp.3302.

History

This code has been under development since 2012; Simon Mudd began the project and David Milodowski, Stuart Grieve and Declan Valters have all contributed to its development. Fiona Clubb, Declan Valters and Jen Merritt at the University of Edinburgh began beta testing in January 2013. Rahul Devrani and Vimal Singh of the University of Dehli began beta testing in April of 2013, and TC Hales of Cardiff University began beta testing in May 2013. The working version of the code used in the manuscript was finished in June 2013.

References

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Nr. of publications:	1
Total citations:	144
h-index:	1
m-quotient:	0.1

Featured publication(s)	Year	Model described	Type of Reference	Citations
Mudd, Simon M.; Attal, Mikaël; Milodowski, David T.; Grieve, Stuart W. D.; Valters, Declan A.; 2014. A statistical framework to quantify spatial variation in channel gradients using the integral method of channel profile analysis: CHANNEL SEGMENT FITTING. Journal of Geophysical Research: Earth Surface, 119, 138–152. 10.1002/2013JF002981 (View/edit entry)	2014	Chi analysis tools	Model overview	144
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Issues

If you find bugs, email simon.m.mudd _at_ ed.ac.uk

Help

Go to the 'other' tab in this wiki: documentation and instructions are found in two .pdf documents available there.

Input Files

See documentation: go to 'other' tab in this wiki.

Output Files

See documentation: go to 'other' tab in this wiki.