landlab.components.weathering.exponential_weathering

Created on Fri Apr 8 08:32:48 2016.

@author: RCGlade

class ExponentialWeatherer[source]

Bases: Component

Calculate exponential weathering of bedrock on hillslopes.

Uses exponential soil production function in the style of Ahnert (1976).

Consider that w0 is the maximum soil production rate and that w_star is the characteristic soil production depth. The soil production rate w0 is given as a function of the soil depth:

soil_production =  w0 * exp(-soil__depth / w_star)

The ExponentialWeatherer only calculates soil production at core nodes.

An alternative version which uses the analytical integral of production through time is available at the component ExponentialWeathererIntegrated.

Examples

>>> import numpy as np
>>> from landlab import RasterModelGrid
>>> from landlab.components import ExponentialWeatherer
>>> mg = RasterModelGrid((5, 5))
>>> soilz = mg.add_zeros("soil__depth", at="node")
>>> soilrate = mg.add_ones("soil_production__rate", at="node")
>>> expw = ExponentialWeatherer(mg)
>>> expw.calc_soil_prod_rate()
>>> np.allclose(mg.at_node["soil_production__rate"], 1.0)
True

References

Required Software Citation(s) Specific to this Component

Barnhart, K., Glade, R., Shobe, C., Tucker, G. (2019). Terrainbento 1.0: a Python package for multi-model analysis in long-term drainage basin evolution. Geoscientific Model Development 12(4), 1267–1297. https://dx.doi.org/10.5194/gmd-12-1267-2019

Additional References

Ahnert, F. (1976). Brief description of a comprehensive three-dimensional process-response model of landform development Z. Geomorphol. Suppl. 25, 29 - 49.

Armstrong, A. (1976). A three dimensional simulation of slope forms. Zeitschrift für Geomorphologie 25, 20 - 28.

Parameters:

  • grid (ModelGrid) – Landlab ModelGrid object

  • soil_production_maximum_rate (float, array of float) – Maximum weathering rate for bare bedrock

  • soil_production_decay_depth (float, array of float) – Characteristic weathering depth

__init__(grid, soil_production_maximum_rate=1.0, soil_production_decay_depth=1.0)[source]
Parameters:

  • grid (ModelGrid) – Landlab ModelGrid object

  • soil_production_maximum_rate (float, array of float) – Maximum weathering rate for bare bedrock

  • soil_production_decay_depth (float, array of float) – Characteristic weathering depth

static __new__(cls, *args, **kwds)
calc_soil_prod_rate()[source]

Calculate soil production rate.

cite_as = '\n    @article{barnhart2019terrain,\n      author = {Barnhart, Katherine R and Glade, Rachel C and Shobe, Charles M\n                and Tucker, Gregory E},\n      title = {{Terrainbento 1.0: a Python package for multi-model analysis in\n                long-term drainage basin evolution}},\n      doi = {10.5194/gmd-12-1267-2019},\n      pages = {1267---1297},\n      number = {4},\n      volume = {12},\n      journal = {Geoscientific Model Development},\n      year = {2019},\n    }\n    '
property coords

Return the coordinates of nodes on grid attached to the component.

property current_time

Current time.

Some components may keep track of the current time. In this case, the current_time attribute is incremented. Otherwise it is set to None.

Return type:

current_time

property decay_depth

Maximum rate of weathering (m/yr).

definitions = (('soil__depth', 'Depth of soil or weathered bedrock'), ('soil_production__rate', 'rate of soil production at nodes'))
classmethod from_path(grid, path)

Create a component from an input file.

Parameters:

  • grid (ModelGrid) – A landlab grid.

  • path (str or file_like) – Path to a parameter file, contents of a parameter file, or a file-like object.

Returns:

A newly-created component.

Return type:

Component

property grid

Return the grid attached to the component.

initialize_optional_output_fields()

Create fields for a component based on its optional field outputs, if declared in _optional_var_names.

This method will create new fields (without overwrite) for any fields output by the component as optional. New fields are initialized to zero. New fields are created as arrays of floats, unless the component also contains the specifying property _var_type.

initialize_output_fields(values_per_element=None)

Create fields for a component based on its input and output var names.

This method will create new fields (without overwrite) for any fields output by, but not supplied to, the component. New fields are initialized to zero. Ignores optional fields. New fields are created as arrays of floats, unless the component specifies the variable type.

Parameters:

values_per_element (int (optional)) – On occasion, it is necessary to create a field that is of size (n_grid_elements, values_per_element) instead of the default size (n_grid_elements,). Use this keyword argument to acomplish this task.

input_var_names = ('soil__depth',)
property maximum_weathering_rate

Maximum rate of weathering (m/yr).

name = 'ExponentialWeatherer'
optional_var_names = ()
output_var_names = ('soil_production__rate',)
run_one_step()[source]
Parameters:

dt (float) – Used only for compatibility with standard run_one_step.

property shape

Return the grid shape attached to the component, if defined.

unit_agnostic = True
units = (('soil__depth', 'm'), ('soil_production__rate', 'm/yr'))
classmethod var_definition(name)

Get a description of a particular field.

Parameters:

name (str) – A field name.

Returns:

A description of each field.

Return type:

tuple of (name, *description*)

classmethod var_help(name)

Print a help message for a particular field.

Parameters:

name (str) – A field name.

classmethod var_loc(name)

Location where a particular variable is defined.

Parameters:

name (str) – A field name.

Returns:

The location (‘node’, ‘link’, etc.) where a variable is defined.

Return type:

str

var_mapping = (('soil__depth', 'node'), ('soil_production__rate', 'node'))
classmethod var_type(name)

Returns the dtype of a field (float, int, bool, str…).

Parameters:

name (str) – A field name.

Returns:

The dtype of the field.

Return type:

dtype

classmethod var_units(name)

Get the units of a particular field.

Parameters:

name (str) – A field name.

Returns:

Units for the given field.

Return type:

str