# Real topography model¶

Using the bathymetric/topographic grid produced with ETOPO1 using badlands companion, we investigate the geomorphological evolution of a real topography under sea-level fall and uniform precipitation.

## Initial settings¶

Initial elevation Selevel

For this model, we use the stream power law sediment transport model which scale the incision rate $E$ as a power function of surface water discharge $A$ and slope $S=\nabla z$:

$$E = \kappa A^m (\nabla z)^n$$

where $\kappa$ is the erodibility coefficient dependent on lithology and mean precipitation rate, channel width, flood frequency, channel hydraulics.

The values given to these parameters ($\kappa$, $m$, $n$) need to be set in the XmL input file.

First we initialise the model and set the path to the XmL input file.

You can edit the XmL configuration file at /edit/volume/Examples/etopo/etopo.xml.

To view the complete XmL options you can follow this link to github page: complete.xml.

In [ ]:
from pyBadlands.model import Model as badlandsModel

# Initialise model
# Define the XmL input file


We can run the model for a given period. The end time in the XmL input file is set to 500k years but you might want to run the model for a coupled of iterations and check the output before running the model for the entire simulation time. This is done by putting the time in the run_to_time function.

Here we go for the full time directly... it should take less than 10 minutes on a single processor if you keep the initial setting unchanged. By changing the resfactor in the XmL input file you will change both the resolution and the computation time.

In [ ]:
# Run model for 500k years. This takes a few minutes.
model.run_to_time(500000)


# Visualise in Paraview¶

For an in-depth visualisation of the model output it is recommended to install on your local machine a visualisation package such as Paraview or Visit.

Badlands outputs are created in the directory you've specified in your XmL input file. In cases where you have ran several instances of the same input you will end up with multiple directories with the same name followed with the simulation number.

The folder contains xdmf series files:

• tin.series.xdmf which will display the time series of surface evolution.
• flow.series.xdmf which will display the time series of drainage network evolution.

### Topographic changes¶

Time step 20 Time step 50
Time step 80 Time step 100

### Erosion/deposition changes¶

Time step 20 Time step 50
Time step 80 Time step 100
In [ ]: