Shallow landslides, landscape evolution, and land management 1 Tectonic and Climatic Influences on Hillslope Evolution: Numerical Modeling TAKE HOME FINAL EXAMINATION GEOS 4053/5223, Geomorphology,...

The project about use Matlab which Set-up initial form page 3 in part B.
just use commands and interpretation of numerical model results with answer 5 questions in last pages.

not need writing coding.I have attached pdf file explanied everthing and three Matlab scripts for the project.


Shallow landslides, landscape evolution, and land management 1 Tectonic and Climatic Influences on Hillslope Evolution: Numerical Modeling TAKE HOME FINAL EXAMINATION GEOS 4053/5223, Geomorphology, Spring 2018 Due date: Wednesday, May. 9, 5pm. No late examinations will be accepted. TWO IMPORTANT NOTES 1. Turn in the take-home final by sending a word document or pdf with all of your answers and plots to Dr Marshall ([email protected]). 2. The work you hand in must be your own. This includes all the analyses. There is to be no group work at all on this final. Please consult with your instructor or TA with any conceptual or technical problems you encounter. Goals Landscapes reflect complex interactions between tectonics, rock properties, climate, and erosional processes. Using the equation for mass conservation and theoretical equations that describe sediment transport on hillslopes and in valleys, we can simulate how a theoretical landscape will evolve in response to changes in the rate of tectonic uplift or the climate-related sediment transport efficiency. Numerous questions regarding how landscapes are linked to tectonic and climatic processes have been posed. For example, how does hillslope relief change in response to a doubling of the uplift rate? Or, will hillslopes be more or less convex given slower rates of soil creep? Also, how long does it take for a hillslope to adjust its morphology in response to changes in uplift rate? These specific questions are difficult if not impossible to test in a field setting. Thus, we use numerical simulations to analyze landscape response. This project is intended to introduce you to the analysis and interpretation of numerical model results. Although you will not be asked to derive the numerical theory or write computer code, you will use an existing program to explore questions regarding hillslope evolution. The general methodology of conducting hillslope evolution simulations entails the following components: 1. Establishing the initial conditions of the hillslope…What does the landform look like in the beginning? Does it start out flat? Steep? Rounded? Concave? Often, we have little information to go on. 2. Choose the appropriate mass conversation equation…For this project, you’ll use the following: ( ) U x q t z s + ∂ ∂ −= ∂ ∂ (1) where z is elevation, t is time, qs is sediment flux, x is horizontal distance, and U is the rate of tectonic uplift. For the purpose of this project, you can think of rock uplift (U) and the rate of channel incision as being synonymous, as we’re assuming that channels near the base of hillslopes incise at a rate equal to the rock uplift rate. 3. Choose an appropriate transport model (qs)…In this project, you’ll simulate hillslopes where the following transport model is commonly used: qs qs Z 0-X X Hillslope length (L)Channel incision (tectonic uplift) 2 s zq K x ∂ = − ∂ (2a) where K (m2/yr) is the transport coefficient which varies as a function of climate, vegetation, and soil properties. Most generally, it reflects the disturbance-driven energy that transports soil. 4. Choose an appropriate soil production model. In this project, you’ll use the depth-dependent production model in which soil production rates, P, decrease exponentially with soil depth: 0 hP P e α−= (2b) where h is soil depth (m), P0 is the maximum production rate (when h=0), and α is the exponential decay constant (1/m). For a steady state hillslope (where rock uplift equals production, i.e., U=P), this model predicts that soil depth will be spatially uniform and given by: ( )0ln steady U P h α = − (2c) 5. Choose boundary conditions that will drive the system’s behavior. For this project, you’ll specify the rate of channel incision at the hillslope margins, which is assumed to be equal to the rate of tectonic uplift (U). Requirements For this project, you will be spend some time in the computer cluster (101 GEOS) or on your own computer conducting hillslope evolution experiments using a computer program called MATLAB. In contrast to the field project reports, you will NOT be asked to synthesize your findings into a coherent report. Instead, you’ll type your responses to specific questions and turn in those responses along with plots that you generate with the computer program. In order to maximize your efficiency, you should have a word processing document and spreadsheet program (e.g. Excel) open while you are running the computer simulations. This will allow you to type in your answers as you go such that you’ll simply need to print the document and the relevant plots. We STRONGLY suggest you read through this document completely, before you start running the simulations, and note what information you will need to track be able to answer the questions completely. This handout will walk you through the process of opening and using MATLAB to perform the necessary analyses and produce relevant figures. Computer cluster usage If working in GEAR 101 you can check the class schedule hung in GEAR 216 to see when the room is open the week before finals. If you don’t have the access code to the room, ask the the office staff in GEAR 216 for the room code. During final week the computer room is reserved Tuesday, May 8 from 12:45 to 2:45. Software For this project, you’ll be using MATLAB, which is a sophisticated and powerful computational and visualization environment. MATLAB is a command-line driven program, which means that you have to type in your commands in order to get the program to perform tasks. As a result, it’s important that you follow these directions exactly to avoid confusion. Of course, if you need help, please contact us. If you’d like to get a general introduction to how MATLAB works, check the following link: http://www.mathworks.com/academia/student_center/tutorials/launchpad.html If you want to download MATLAB on your own machine (it is free for students), you can do so by visiting: https://its.uark.edu/help/ta/379.php http://www.mathworks.com/academia/student_center/tutorials/launchpad.html https://its.uark.edu/help/ta/379.php 3 EXAMPLE SIMULATION A. Starting up MATLAB • Logon to a machine with MATLAB installed. The GEOS 101 computer cluster machines have MATLAB or you can install it on your own machine (see above). • Open the program “MATLAB”, which should be on the Desktop or in the Programs folder. • Once Matlab opens change the CURRENT DIRECTORY: Near the top of the main window, change the directory by clicking on the box with the 3 dots “…” Create and name a directory on the desktop for your files and set this folder as the CURRENT DIRECTORY. • If you get an error that reads ‘ ‘ is not found in the current folder or on the MATLAB path, but exists in ‘ ’, you are not in the proper folder. Navigate to it as described above OR you can add the folder to the MATLAB path by right-clicking on the proper folder once you see it in the current folder window and choosing ‘Add to Path’. • You’ll need to copy three MATLAB script files into the directory you just created. Open blackboard and navigate to the FINAL directory in Course Documents. Save the files “dif410.m”, “diffsoil1d.m”, and “difmovie.m” into your directory, this will enable you to run them using MATLAB. • When you logoff, be sure to save your spreadsheet and word processing documents to a USB flash drive or your personal directory or you can email them to yourself. Files saved on the Desktop will not necessarily be there if you log off and return to finish working at a later time. B. Set-up initial hillslope conditions • CREATE THE X-REFERENCE FRAME (SEE FIGURE ABOVE). At the prompt in the MATLAB command window, type the following (text that appears in italics is what you’ll input. You don’t need to type the “double arrows”. Be sure to remember the semi-colon that follows most commands) (this suppresses the output on the viewing window, which can be lengthy when working with big datasets): >> x=[0:40]; This creates a row of 41 numbers: (0,1,2,…,39,40), which will serve as your x-coordinate axis as shown in the figure above. In this project, we’ll be simulating a symmetrical hillslope (see figure above), so that the hillslope length (L) for this example is 20m. In other words, the distance from the drainage divide to the channel is 20 m and the distance from channel to channel is 40 m. • CREATE THE INITIAL LANDSCAPE SURFACE, type the following: >> z(1:41)=100; This creates a z value for each of the 41 points along the x-axis that you just created. Each z- value is set equal to 100, so the morphology of your initial hillslope is flat. You can determine the value of z at any point along the profile by typing the following command: >> z(5) This command will return the value of z-value for x=5m, such that it’s 5m upslope from the channel margin. The return value should be 100 in this case. • PLOT THE INITIAL HILLSLOPE GEOMETRY, type the following: >> plot(x,z); This command makes a plot of the initial hillslope geometry. A new window showing the plot should appear on your monitor, you can resize the plot window so that it’s visible while you are typing commands into the command line. You can keep this plot window open and whenever you type another “plot” command, it will redraw a plot in this window. If you would like to keep the figure docked rather than re-opening the window each time you redraw a plot in the window you can type the following: >>set (0,'DefaultFigureWindowStyle','docked'); 4 C. Perform hillslope evolution experiment • NOW YOU’RE READY TO EVOLVE THE HILLSLOPE. You need to choose input parameter values. For the first example, let’s use the following
May 03, 2020
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