Workshop EGU2015

GM11.3/SC48 Quantitative interrogation of high-resolution DTMs

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Mon, 13 Apr, 13:30–15:00 / Room G2

Analysing bedrock river profiles using chi-plots

Digital elevation models (DEMs) are the foundation of many studies in geomorphology. Methods to quantitatively interrogate these data are thus one of the keys to understanding the processes that shape the Earth and their driving forces. River profiles in particular have attracted the attention of geomorphologists as their shape reflects the tectonic and climatic past. Extracting and analysing river profiles from DEMs, however, is challenged by noisy topographic data often affected by artifacts.

In this workshop, we will explore various techniques to extract and analyse river profiles from DEMs to account for the problems associated with DEMs in high mountain landscapes. We will use TopoToolbox, a software written in MATLAB language for the analysis of DEMs (Schwanghart and Scherler, 2014) and go through the entire work flow including preprocessing a DEM and deriving and modifying river networks. Finally, we aim at calculating Chi-plots, a new technique to analyse bedrock river profiles and alternative to slope-area plots which is less sensitive to noisy topographic data (Perron and Royden, 2012).

Participants are invited to bring their own laptops to work hands-on on the data and code. TopoToolbox requires MATLAB with a version newer than R2011b including the Image Processing Toolbox. Basic knowledge in MATLAB is an advantage but not a requirement.

Software

Download the latest working-copy of TopoToolbox here.

Data

Download data for Exercise 1 and 2 here.

Download output of a Landscape Evolution Model (transient signal as a result of baselevel lowering) here.

Presentation

A pdf of the presentation can be downloaded here.

References

Harkins N, Kirby E, Heimsath A, Robinson R, Reiser U. 2007. Transient fluvial incision in the headwater of the Yellow River, northeastern Tibet, China. Journal of Geophysical Research 112 : F03S04–F03S04. [DOI: 10.1029/2006JF000570]

Perron JT, Royden L. 2013. An integral approach to bedrock river profile analysis. Earth Surface Processes and Landforms 38 : 570–576. [DOI: 10.1002/esp.3302]

Royden L, Perron JT. 2013. Solutions of the stream power equation and application to the evolution of river longitudinal profiles. Journal of Geophysical Research 118 : 1–22.

Schwanghart, W., Scherler, D. (2014): TopoToolbox 2 – MATLAB-based software for topographic analysis and modeling in Earth surface sciences. Earth Surface Dynamics, 2, 1-7. [DOI: 10.5194/esurf-2-1-2014]

Willett SD, McCoy SW, Perron JT, Goren L, Chen C-Y. 2014. Dynamic Reorganization of River Basins. Science 343 : 1248765. [DOI: 10.1126/science.1248765]

Please leave a comment or send me an email if you want to provide feedback on this short course.