class BasicSt

Model BasicSt

terrainbento Model BasicSt program.

Erosion model program using linear diffusion and stream power. Discharge is calculated from drainage area, infiltration capacity (a parameter), and precipitation rate, which is a stochastic variable.

Landlab components used:

  1. FlowAccumulator

  2. DepressionFinderAndRouter (optional)

  3. FastscapeEroder

  4. LinearDiffuser

  5. PrecipitationDistribution

class BasicSt(clock, grid, m_sp=0.5, n_sp=1.0, water_erodibility=0.0001, regolith_transport_parameter=0.1, infiltration_capacity=1.0, **kwargs)[source]

Bases: terrainbento.base_class.stochastic_erosion_model.StochasticErosionModel

BasicSt model program.

This model program that evolves a topographic surface, \(\eta (x,y,t)\), with the following governing equation:

\[\frac{\partial \eta}{\partial t} = -K_{q}\hat{Q}^{m}S^{n} + D\nabla^2 \eta\]

where \(\hat{Q}\) is the local stream discharge (the hat symbol indicates that it is a random-in-time variable), \(S\) is the local slope gradient, \(m\) and \(n\) are the discharge and slope exponents, respectively, \(K\) is the erodibility by water, and \(D\) is the regolith transport parameter.

Refer to Barnhart et al. (2019) Table 5 for full list of parameter symbols, names, and dimensions.

The following at-node 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, infiltration_capacity=1.0, **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.

  • infiltration_capacity (float, optional) – Infiltration capacity (\(I_m\)). Default is 1.0.

  • **kwargs – Keyword arguments to pass to StochasticErosionModel. These arguments control the discharge \(\hat{Q}\).

Returns

BasicSt

Return type

model object

Examples

This is a minimal example to demonstrate how to construct an instance of model BasicSt. For more detailed examples, including steady-state 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, BasicSt
>>> clock = Clock(start=0, stop=100, step=1)
>>> grid = RasterModelGrid((5,5))
>>> _ = random(grid, "topographic__elevation")

Construct the model.

>>> model = BasicSt(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 time-step of duration step.

The run_one_step method does the following:

  1. Creates rain and runoff, then directs and accumulates flow.

  2. Assesses the location, if any, of flooded nodes where erosion should not occur.

  3. Calculates precipitation, runoff, discharge, and detachment-limited erosion by water.

  4. Calculates topographic change by linear diffusion.

  5. Finalizes the step using the ErosionModel base class function finalize__run_one_step. This function updates all boundary handlers handlers by step and increments model time by step.

Parameters

step (float) – Increment of time for which the model is run.

main()[source]

Execute model.