SoilMoisture: Compute the decay of soil moisture saturation at storm-interstorm time period#

class SoilMoisture(*args, **kwds)[source]#

Bases: Component

Landlab component that simulates root-zone average soil moisture at each cell using inputs of potential evapotranspiration, live leaf area index, and vegetation cover.

This component uses a single soil moisture layer and models soil moisture loss through transpiration by plants, evaporation by bare soil, and leakage. The solution of water balance is based on Laio et. al 2001. The component requires fields of initial soil moisture, rainfall input (if any), time to the next storm and potential transpiration.

Ref: Laio, F., Porporato, A., Ridolfi, L., & Rodriguez-Iturbe, I. (2001). Plants in water-controlled ecosystems: active role in hydrologic processes and response to water stress: II. Probabilistic soil moisture dynamics. Advances in Water Resources, 24(7), 707-723.

Code author: Sai Nudurupati and Erkan Istanbulluoglu

Examples

>>> from landlab import RasterModelGrid
>>> from landlab.components.soil_moisture import SoilMoisture
>>> grid = RasterModelGrid((5, 4), xy_spacing=(0.2, 0.2))
>>> SoilMoisture.name
'Soil Moisture'
>>> sorted(SoilMoisture.output_var_names)
['soil_moisture__root_zone_leakage',
 'soil_moisture__saturation_fraction',
 'surface__evapotranspiration',
 'surface__runoff',
 'vegetation__water_stress']
>>> sorted(SoilMoisture.units)
[('rainfall__daily_depth', 'mm'),
 ('soil_moisture__initial_saturation_fraction', 'None'),
 ('soil_moisture__root_zone_leakage', 'mm'),
 ('soil_moisture__saturation_fraction', 'None'),
 ('surface__evapotranspiration', 'mm'),
 ('surface__potential_evapotranspiration_rate', 'mm'),
 ('surface__runoff', 'mm'),
 ('vegetation__cover_fraction', 'None'),
 ('vegetation__live_leaf_area_index', 'None'),
 ('vegetation__plant_functional_type', 'None'),
 ('vegetation__water_stress', 'None')]
>>> grid["cell"]["vegetation__plant_functional_type"] = np.zeros(
...     grid.number_of_cells, dtype=int
... )
>>> _ = grid.add_zeros("vegetation__cover_fraction", at="cell")
>>> _ = grid.add_zeros("vegetation__live_leaf_area_index", at="cell")
>>> _ = grid.add_zeros("surface__potential_evapotranspiration_rate", at="cell")
>>> _ = grid.add_zeros("soil_moisture__initial_saturation_fraction", at="cell")
>>> _ = grid.add_zeros("rainfall__daily_depth", at="cell")
>>> SM = SoilMoisture(grid)
>>> SM.grid.number_of_cell_rows
3
>>> SM.grid.number_of_cell_columns
2
>>> SM.grid is grid
True
>>> import numpy as np
>>> np.allclose(grid.at_cell["soil_moisture__saturation_fraction"], 0.0)
True
>>> grid["cell"]["surface__potential_evapotranspiration_rate"] = np.array(
...     [0.2554777, 0.2554777, 0.22110221, 0.22110221, 0.24813062, 0.24813062]
... )
>>> grid["cell"]["soil_moisture__initial_saturation_fraction"] = 0.75 * np.ones(
...     grid.number_of_cells
... )
>>> grid["cell"]["vegetation__live_leaf_area_index"] = 2.0 * np.ones(
...     grid.number_of_cells
... )
>>> grid["cell"]["vegetation__cover_fraction"] = np.ones(grid.number_of_cells)
>>> grid["cell"]["rainfall__daily_depth"] = 25.0 * np.ones(grid.number_of_cells)
>>> SM.current_time = 0.5
>>> current_time = SM.update()
>>> np.allclose(grid.at_cell["soil_moisture__saturation_fraction"], 0.0)
False

References

Required Software Citation(s) Specific to this Component

None Listed

Additional References

Laio, F., Porporato, A., Ridolfi, L., Rodriguez-Iturbe, I. (2001). Plants in water-controlled ecosystems: active role in hydrologic processes and response to water stress II. Probabilistic soil moisture dynamics. Advances in Water Resources 24(7), 707-723. https://dx.doi.org/10.1016/s0309-1708(01)00005-7

Parameters:

  • grid (RasterModelGrid) – A grid.

  • runon (float, optional) – Runon from higher elevation (mm).

  • f_bare (float, optional) – Fraction to partition PET for bare soil (None).

  • soil_ew (float, optional) – Residual Evaporation after wilting (mm/day).

  • intercept_cap (float, optional) – Plant Functional Type (PFT) specific full canopy interception capacity.

  • zr (float, optional) – Root depth (m).

  • I_B (float, optional) – Infiltration capacity of bare soil (mm/h).

  • I_V (float, optional) – Infiltration capacity of vegetated soil (mm/h).

  • pc (float, optional) – Soil porosity (None).

  • fc (float, optional) – Soil saturation degree at field capacity (None).

  • sc (float, optional) – Soil saturation degree at stomatal closure (None).

  • wp (float, optional) – Soil saturation degree at wilting point (None).

  • hgw (float, optional) – Soil saturation degree at hygroscopic point (None).

  • beta (float, optional) – Deep percolation constant = 2*b+3 where b is water retention (None).

  • LAI_max (float, optional) – Maximum leaf area index (m^2/m^2).

  • LAIR_max (float, optional) – Reference leaf area index (m^2/m^2).

  • method (str) – Method used

  • Tr (float, optional) – Storm duration (hours).

  • Tb (float, optional) – Inter-storm duration (hours).

  • current_time (float) – Current time (years).

property Tb#

Storm duration (hours).

property Tr#

Inter-storm duration (hours).

__init__(grid, runon=0.0, f_bare=0.7, soil_ew=0.1, intercept_cap_grass=1.0, zr_grass=0.3, I_B_grass=20.0, I_V_grass=24.0, pc_grass=0.43, fc_grass=0.56, sc_grass=0.33, wp_grass=0.13, hgw_grass=0.1, beta_grass=13.8, LAI_max_grass=2.0, LAIR_max_grass=2.88, intercept_cap_shrub=1.5, zr_shrub=0.5, I_B_shrub=20.0, I_V_shrub=40.0, pc_shrub=0.43, fc_shrub=0.56, sc_shrub=0.24, wp_shrub=0.13, hgw_shrub=0.1, beta_shrub=13.8, LAI_max_shrub=2.0, LAIR_max_shrub=2.0, intercept_cap_tree=2.0, zr_tree=1.3, I_B_tree=20.0, I_V_tree=40.0, pc_tree=0.43, fc_tree=0.56, sc_tree=0.22, wp_tree=0.15, hgw_tree=0.1, beta_tree=13.8, LAI_max_tree=4.0, LAIR_max_tree=4.0, intercept_cap_bare=1.0, zr_bare=0.15, I_B_bare=20.0, I_V_bare=20.0, pc_bare=0.43, fc_bare=0.56, sc_bare=0.33, wp_bare=0.13, hgw_bare=0.1, beta_bare=13.8, LAI_max_bare=0.01, LAIR_max_bare=0.01, method='Grid', Tb=24.0, Tr=0.0, current_time=0)[source]#
Parameters:

  • grid (RasterModelGrid) – A grid.

  • runon (float, optional) – Runon from higher elevation (mm).

  • f_bare (float, optional) – Fraction to partition PET for bare soil (None).

  • soil_ew (float, optional) – Residual Evaporation after wilting (mm/day).

  • intercept_cap (float, optional) – Plant Functional Type (PFT) specific full canopy interception capacity.

  • zr (float, optional) – Root depth (m).

  • I_B (float, optional) – Infiltration capacity of bare soil (mm/h).

  • I_V (float, optional) – Infiltration capacity of vegetated soil (mm/h).

  • pc (float, optional) – Soil porosity (None).

  • fc (float, optional) – Soil saturation degree at field capacity (None).

  • sc (float, optional) – Soil saturation degree at stomatal closure (None).

  • wp (float, optional) – Soil saturation degree at wilting point (None).

  • hgw (float, optional) – Soil saturation degree at hygroscopic point (None).

  • beta (float, optional) – Deep percolation constant = 2*b+3 where b is water retention (None).

  • LAI_max (float, optional) – Maximum leaf area index (m^2/m^2).

  • LAIR_max (float, optional) – Reference leaf area index (m^2/m^2).

  • method (str) – Method used

  • Tr (float, optional) – Storm duration (hours).

  • Tb (float, optional) – Inter-storm duration (hours).

  • current_time (float) – Current time (years).

initialize(runon=0.0, f_bare=0.7, soil_ew=0.1, intercept_cap_grass=1.0, zr_grass=0.3, I_B_grass=20.0, I_V_grass=24.0, pc_grass=0.43, fc_grass=0.56, sc_grass=0.33, wp_grass=0.13, hgw_grass=0.1, beta_grass=13.8, LAI_max_grass=2.0, LAIR_max_grass=2.88, intercept_cap_shrub=1.5, zr_shrub=0.5, I_B_shrub=20.0, I_V_shrub=40.0, pc_shrub=0.43, fc_shrub=0.56, sc_shrub=0.24, wp_shrub=0.13, hgw_shrub=0.1, beta_shrub=13.8, LAI_max_shrub=2.0, LAIR_max_shrub=2.0, intercept_cap_tree=2.0, zr_tree=1.3, I_B_tree=20.0, I_V_tree=40.0, pc_tree=0.43, fc_tree=0.56, sc_tree=0.22, wp_tree=0.15, hgw_tree=0.1, beta_tree=13.8, LAI_max_tree=4.0, LAIR_max_tree=4.0, intercept_cap_bare=1.0, zr_bare=0.15, I_B_bare=20.0, I_V_bare=20.0, pc_bare=0.43, fc_bare=0.56, sc_bare=0.33, wp_bare=0.13, hgw_bare=0.1, beta_bare=13.8, LAI_max_bare=0.01, LAIR_max_bare=0.01)[source]#
Parameters:

  • grid (RasterModelGrid) – A grid.

  • runon (float, optional) – Runon from higher elevation (mm).

  • f_bare (float, optional) – Fraction to partition PET for bare soil (None).

  • soil_ew (float, optional) – Residual Evaporation after wilting (mm/day).

  • intercept_cap (float, optional) – Plant Functional Type (PFT) specific full canopy interception capacity.

  • zr (float, optional) – Root depth (m).

  • I_B (float, optional) – Infiltration capacity of bare soil (mm/h).

  • I_V (float, optional) – Infiltration capacity of vegetated soil (mm/h).

  • pc (float, optional) – Soil porosity (None).

  • fc (float, optional) – Soil saturation degree at field capacity (None).

  • sc (float, optional) – Soil saturation degree at stomatal closure (None).

  • wp (float, optional) – Soil saturation degree at wilting point (None).

  • hgw (float, optional) – Soil saturation degree at hygroscopic point (None).

  • beta (float, optional) – Deep percolation constant = 2*b+3 where b is water retention (None).

  • (None) (parameter) –

  • LAI_max (float, optional) – Maximum leaf area index (m^2/m^2).

  • LAIR_max (float, optional) – Reference leaf area index (m^2/m^2).

update()[source]#

Update fields with current loading conditions.

This method looks to the properties current_time, Tb, and Tr, and uses their values in updating fields.

assert_method_is_valid(method)[source]#