
class
BasicCv
¶
Model BasicCv¶
terrainbento BasicCv model program.
Erosion model program using linear diffusion, stream power, and discharge proportional to drainage area with climate change.
 Landlab components used:

class
BasicCv
(clock, grid, m_sp=0.5, n_sp=1.0, water_erodibility=0.0001, regolith_transport_parameter=0.1, climate_factor=0.5, climate_constant_date=0.0, **kwargs)[source]¶ Bases:
terrainbento.base_class.erosion_model.ErosionModel
BasicCv model program.
This model program evolves a topographic surface, \(\eta\), with the following governing equation:
\[\frac{\partial \eta}{\partial t} = KQ^{m}S^{n} + D\nabla^2 \eta\]where \(K\) is the fluviel erodibility coefficient, \(Q\) is the local stream discharge, \(S\) is the local slope, \(m\) and \(n\) are the discharge and slope exponent parameters, and \(D\) is the regolith transport parameter.
This model also has a basic parameterization of climate change such that \(K\) varies through time. Between model run onset and a time at which the climate becomes constant, the value of \(K\) linearly changes from \(fK\) to \(K\), at which point it remains at \(K\) for the remainder of the modeling time period.
Refer to Barnhart et al. (2019) Table 5 for full list of parameter symbols, names, and dimensions.
 The following atnode fields must be specified in the grid:
topographic__elevation

__init__
(clock, grid, m_sp=0.5, n_sp=1.0, water_erodibility=0.0001, regolith_transport_parameter=0.1, climate_factor=0.5, climate_constant_date=0.0, **kwargs)[source]¶  Parameters
clock (terrainbento Clock instance) –
grid (landlab model grid instance) – The grid must have all required fields.
m_sp (float, optional) – Drainage area exponent (\(m\)). Default is 0.5.
n_sp (float, optional) – Slope exponent (\(n\)). Default is 1.0.
water_erodibility (float, optional) – Water erodibility (\(K\)). Default is 0.0001.
regolith_transport_parameter (float, optional) – Regolith transport efficiency (\(D\)). Default is 0.1.
climate_factor (float, optional.) – Default is 0.5.(\(f\) )
climate_constant_date (float, optional.) – Model time at which climate becomes constant (\(T_s\)) and water erodibility stabilizes at a value of \(K\). Default is 0.0.
**kwargs – Keyword arguments to pass to
ErosionModel
. Importantly these arguments specify the precipitator and the runoff generator that control the generation of surface water discharge (\(Q\)).
 Returns
Basic
 Return type
model object
Examples
This is a minimal example to demonstrate how to construct an instance of model
Basic
. For more detailed examples, including steadystate test examples, see the terrainbento tutorials.To begin, import the model class.
>>> from landlab import RasterModelGrid >>> from landlab.values import random >>> from terrainbento import Clock, BasicCv >>> clock = Clock(start=0, stop=100, step=1) >>> grid = RasterModelGrid((5,5)) >>> _ = random(grid, "topographic__elevation")
Construct the model.
>>> model = BasicCv(clock, grid)
Running the model with
model.run()
would create output, so here we will just run it one step.>>> model.run_one_step(1.) >>> model.model_time 1.0

run_one_step
(step)[source]¶ Advance model
Basic
for one timestep of duration step.The run_one_step method does the following:
Creates rain and runoff, then directs and accumulates flow.
Assesses the location, if any, of flooded nodes where erosion should not occur.
Updates detachmentlimited erosion based on climate.
Calculates detachmentlimited erosion by water.
Calculates topographic change by linear diffusion.
Finalizes the step using the
ErosionModel
base class function finalize__run_one_step. This function updates all boundary handlers handlers bystep
and increments model time bystep
.
 Parameters
step (float) – Increment of time for which the model is run.