Models
Fastscape provides a few landscape evolution model “presets”, i.e.,
xsimlab.Model objects that can be used as-is or as a basis
for building custom models. Those presets are built from a large
collection of Processes.
For help on how to run and further customize those models, see the Examples section or xarray-simlab’s documentation.
Bootstrap model
bootstrap_model has the minimal set of processes required to
simulate on a 2D uniform grid the evolution of topographic surface
under the action of tectonic and erosion processes.
None of such processes is included. This model only provides the “skeleton” of a landscape evolution model and might be used as a basis to create custom models.
In [1]: from fastscape.models import bootstrap_model
In [2]: bootstrap_model
Out[2]:
<xsimlab.Model (8 processes, 5 inputs)>
grid
shape [in] ('shape_yx',) nb. of grid nodes in (...
length [in] ('shape_yx',) total grid length in (...
boundary
status [in] () or ('border',) node status at bor...
fs_context
tectonics
surf2erode
erosion
cumulative_height [inout] () or ('y', 'x') erosion height accu...
vmotion
topography
elevation [inout] ('y', 'x') surface topography elevation
Basic model
basic_model is a “standard” landscape evolution model that
includes block uplift, (bedrock) channel erosion using the stream
power law and hillslope erosion/deposition using linear diffusion.
Initial topography is a flat surface with random perturbations.
Flow is routed on the topographic surface using a D8, single flow direction algorithm.
All erosion processes are computed on a topographic surface that is first updated by tectonic forcing processes.
In [3]: from fastscape.models import basic_model
In [4]: basic_model
Out[4]:
<xsimlab.Model (16 processes, 12 inputs)>
grid
shape [in] ('shape_yx',) nb. of grid nodes in (y, x)
length [in] ('shape_yx',) total grid length in (y, x)
boundary
status [in] () or ('border',) node status at borders
fs_context
uplift
rate [in] () or ('y', 'x') uplift rate
tectonics
init_topography
seed [in] random seed
surf2erode
diffusion
diffusivity [in] () or ('y', 'x') diffusivity (transport co...
init_erosion
flow
drainage
spl
k_coef [in] () or ('y', 'x') bedrock channel incision ...
area_exp [in] drainage area exponent
slope_exp [in] slope exponent
tol_rel [in] relative tolerance (Gauss-Siedel convergence)
tol_abs [in] absolute tolerance (Gauss-Siedel convergence)
max_iter [in] max nb. of iterations (Gauss-Siedel conver...
erosion
vmotion
topography
terrain
Sediment model
sediment_model is built on top of basic_model ; it tracks the
evolution of both the topographic surface and the bedrock, separated
by a uniform, active layer of sediment.
This model uses an extended version of the stream-power law that also includes channel transport and deposition.
Flow is routed using a multiple flow direction algorithm.
Differential erosion/deposition is enabled for both hillslope and channel processes, i.e., distinct values may be set for the erosion and transport coefficients (bedrock vs soil/sediment).
In [5]: from fastscape.models import sediment_model
In [6]: sediment_model
Out[6]:
<xsimlab.Model (19 processes, 17 inputs)>
grid
shape [in] ('shape_yx',) nb. of grid nodes in...
length [in] ('shape_yx',) total grid length in...
boundary
status [in] () or ('border',) node status at b...
fs_context
uplift
rate [in] () or ('y', 'x') uplift rate
tectonics
init_topography
seed [in] random seed
surf2erode
init_bedrock
active_layer
diffusion
diffusivity_bedrock [in] () or ('y', 'x') bedrock diffusivity
diffusivity_soil [in] () or ('y', 'x') soil (sediment) d...
init_erosion
flow
slope_exp [in] () or ('y', 'x') MFD partioner slo...
drainage
spl
area_exp [in] drainage area exponent
slope_exp [in] slope exponent
tol_rel [in] relative tolerance (Gauss-Siedel c...
tol_abs [in] absolute tolerance (Gauss-Siedel c...
max_iter [in] max nb. of iterations (Gauss-Siede...
k_coef_bedrock [in] () or ('y', 'x') bedrock channel i...
k_coef_soil [in] () or ('y', 'x') soil (sediment) c...
g_coef_bedrock [in] detached bedrock transport/deposit...
g_coef_soil [in] soil (sediment) transport/depositi...
erosion
vmotion
topography
terrain
bedrock
Marine model
marine_model simulates the erosion, transport and deposition of
bedrock or sediment in both continental and submarine environments.
It is built on top of sediment_model to which it
adds a process for sediment transport, deposition and compaction in
the submarine domain (under sea level).
The processes for the initial topography and uplift both allow easy set-up of the two land vs. marine environments.
An additional process keeps track of a fixed number of stratigraphic horizons over time.
In [7]: from fastscape.models import marine_model
In [8]: marine_model
Out[8]:
<xsimlab.Model (22 processes, 32 inputs)>
grid
shape [in] ('shape_yx',) nb. of grid nodes in...
length [in] ('shape_yx',) total grid length in...
boundary
status [in] () or ('border',) node status at b...
fs_context
uplift
x_position [in] position of the clip plane along t...
rate_left [in] uplift rate of the left block
rate_right [in] uplift rate of the right block
tectonics
init_topography
x_left [in] location of the scarp's left limit...
x_right [in] location of the scarp's right limi...
elevation_left [in] elevation on the left side of the ...
elevation_right [in] elevation on the right side of the...
surf2erode
init_bedrock
active_layer
diffusion
diffusivity_bedrock [in] () or ('y', 'x') bedrock diffusivity
diffusivity_soil [in] () or ('y', 'x') soil (sediment) d...
init_erosion
flow
slope_exp [in] () or ('y', 'x') MFD partioner slo...
drainage
spl
area_exp [in] drainage area exponent
slope_exp [in] slope exponent
tol_rel [in] relative tolerance (Gauss-Siedel c...
tol_abs [in] absolute tolerance (Gauss-Siedel c...
max_iter [in] max nb. of iterations (Gauss-Siede...
k_coef_bedrock [in] () or ('y', 'x') bedrock channel i...
k_coef_soil [in] () or ('y', 'x') soil (sediment) c...
g_coef_bedrock [in] detached bedrock transport/deposit...
g_coef_soil [in] soil (sediment) transport/depositi...
marine
ss_ratio_land [in] silt fraction of continental sedim...
porosity_sand [in] surface (reference) porosity of sand
porosity_silt [in] surface (reference) porosity of silt
e_depth_sand [in] e-folding depth of exp. porosity c...
e_depth_silt [in] e-folding depth of exp. porosity c...
diffusivity_sand [in] diffusivity (transport coefficient...
diffusivity_silt [in] diffusivity (transport coefficient...
layer_depth [in] mean depth (thickness) of marine a...
erosion
vmotion
topography
terrain
bedrock
sea
level [in] sea level (elevation)
strati
freeze_time [in] ('horizon',) horizon freezing (dea...