landlab.components.area_slope_transporter.area_slope_transporter

class AreaSlopeTransporter

Bases: Component

Model drainage network evolution for a network of transport-limited rivers in which sediment transport rate is calculated as a power-law function of drainage area and local streamwise slope gradient.

AreaSlopeTransporter is designed to operate together with a flow-routing component such as PriorityFloodFlowRouter, so that each grid node has a defined flow direction toward one of its neighbor nodes. Each core node is assumed to contain one outgoing fluvial channel, and (depending on the drainage structure) zero, one, or more incoming channels. These channels are treated as effectively sub-grid-scale features that are embedded in valleys that have a width of one grid cell. The rate of sediment transport out of a given node is calculated as a generic power function of drainage area, local slope, and a user-specified transport coefficient. Similar power-law formulations have been used, for example, by Willgoose et al. (1991a,b,c, and many papers following that use the SIBERIA model) and Howard (1994, in Water Resources Research).

Parameters:

• grid (ModelGrid) – A Landlab model grid object

• transport_coefficient (float (default 0.0055)) – Dimensional transport efficiency factor

• area_exponent (float (default 1.4)) – Exponent on effective total discharge

• slope_exponent (float (default 2.1)) – Exponent on local streamwise slope gradient

Examples

>>> from landlab import RasterModelGrid
>>> from landlab.components import FlowAccumulator
>>> grid = RasterModelGrid((3, 3), xy_spacing=1000.0)
>>> elev = grid.add_zeros("topographic__elevation", at="node")
>>> grid.status_at_node[grid.perimeter_nodes] = grid.BC_NODE_IS_CLOSED
>>> grid.status_at_node[5] = grid.BC_NODE_IS_FIXED_VALUE
>>> fa = FlowAccumulator(grid)
>>> fa.run_one_step()
>>> transporter = AreaSlopeTransporter(grid)
>>> for _ in range(200):
...     fa.run_one_step()
...     elev[grid.core_nodes] += 1.0
...     transporter.run_one_step(10000.0)
...
>>> int(round(elev[4] * 100))
1068

Initialize AreaSlopeTransporter.

__init__(grid, transport_coefficient=0.0055, area_exponent=1.4, slope_exponent=2.1)

Initialize AreaSlopeTransporter.

static __new__(cls, *args, **kwds)

calc_sediment_rate_of_change()

Update the rate of thickness change of sediment at each core node.

Examples

>>> import numpy as np
>>> from landlab import RasterModelGrid
>>> from landlab.components import FlowAccumulator
>>> grid = RasterModelGrid((3, 4), xy_spacing=100.0)
>>> elev = grid.add_zeros("topographic__elevation", at="node")
>>> elev[:] = 0.01 * grid.x_of_node
>>> grid.status_at_node[grid.perimeter_nodes] = grid.BC_NODE_IS_CLOSED
>>> grid.status_at_node[4] = grid.BC_NODE_IS_FIXED_VALUE
>>> fa = FlowAccumulator(grid)
>>> fa.run_one_step()
>>> transporter = AreaSlopeTransporter(grid)
>>> transporter.calc_sediment_rate_of_change()
>>> np.round(transporter._sediment_outflux[4:7], 3)
array([0.   , 0.365, 0.138])
>>> np.round(transporter._sediment_influx[4:7], 3)
array([0.365, 0.138, 0.   ])
>>> np.round(transporter._dzdt[5:7], 8)
array([-2.264e-05, -1.382e-05])

calc_transport_capacity()

Calculate and return bed-load transport capacity.

Calculation uses power-law approach, and provides volume per time rate.

Examples

>>> from landlab import RasterModelGrid
>>> from landlab.components import FlowAccumulator
>>> grid = RasterModelGrid((3, 3), xy_spacing=100.0)
>>> elev = grid.add_zeros("topographic__elevation", at="node")
>>> elev[3:] = 1.0
>>> fa = FlowAccumulator(grid)
>>> fa.run_one_step()
>>> transporter = AreaSlopeTransporter(grid)
>>> transporter.calc_transport_capacity()
>>> int(transporter._sediment_outflux[4] * 1000)
138

cite_as = ''

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

definitions = (('drainage_area', "Upstream accumulated surface area contributing to the node's discharge"), ('flow__link_to_receiver_node', 'ID of link downstream of each node, which carries the discharge'), ('flow__receiver_node', 'Node array of receivers (node that receives flow from current node)'), ('flow__upstream_node_order', 'Node array containing downstream-to-upstream ordered list of node IDs'), ('sediment__rate_of_change', 'Time rate of change of sediment thickness'), ('sediment__volume_influx', 'Volumetric incoming streamwise sediment transport rate'), ('sediment__volume_outflux', 'Volumetric outgoing streamwise sediment transport rate'), ('topographic__elevation', 'Land surface topographic elevation'), ('topographic__steepest_slope', 'The steepest *downhill* slope'))

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 = ('drainage_area', 'flow__link_to_receiver_node', 'flow__receiver_node', 'flow__upstream_node_order', 'topographic__elevation', 'topographic__steepest_slope')

name = 'AreaSlopeTransporter'

optional_var_names = ()

output_var_names = ('sediment__rate_of_change', 'sediment__volume_influx', 'sediment__volume_outflux', 'topographic__elevation')

run_one_step(dt)

Advance solution by time interval dt.

Examples

>>> import numpy as np
>>> from landlab import RasterModelGrid
>>> from landlab.components import FlowAccumulator
>>> grid = RasterModelGrid((3, 4), xy_spacing=100.0)
>>> elev = grid.add_zeros("topographic__elevation", at="node")
>>> elev[:] = 0.01 * grid.x_of_node
>>> grid.status_at_node[grid.perimeter_nodes] = grid.BC_NODE_IS_CLOSED
>>> grid.status_at_node[4] = grid.BC_NODE_IS_FIXED_VALUE
>>> fa = FlowAccumulator(grid)
>>> fa.run_one_step()
>>> transporter = AreaSlopeTransporter(grid)
>>> transporter.run_one_step(10000.0)
>>> np.round(elev[4:7], 4)
array([0.    , 0.7736, 1.8618])

property shape

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

unit_agnostic = True

units = (('drainage_area', 'm**2'), ('flow__link_to_receiver_node', '-'), ('flow__receiver_node', '-'), ('flow__upstream_node_order', '-'), ('sediment__rate_of_change', 'm/y'), ('sediment__volume_influx', 'm**3/y'), ('sediment__volume_outflux', 'm**3/y'), ('topographic__elevation', 'm'), ('topographic__steepest_slope', '-'))

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 = (('drainage_area', 'node'), ('flow__link_to_receiver_node', 'node'), ('flow__receiver_node', 'node'), ('flow__upstream_node_order', 'node'), ('sediment__rate_of_change', 'node'), ('sediment__volume_influx', 'node'), ('sediment__volume_outflux', 'node'), ('topographic__elevation', 'node'), ('topographic__steepest_slope', '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