landlab

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

class SoilMoisture(self, 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, **kwds)[source]

Bases: landlab.core.model_component.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), 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))
>>> 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.)
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. * np.ones(grid.number_of_cells))
>>> grid['cell']['vegetation__cover_fraction']= (
...        np.ones(grid.number_of_cells))
>>> current_time = 0.5
>>> grid['cell']['rainfall__daily_depth'] = (
...        25. * np.ones(grid.number_of_cells))
>>> current_time = SM.update(current_time)
>>> np.allclose(grid.at_cell['soil_moisture__saturation_fraction'], 0.)
False
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).

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, **kwds)[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).

parameter (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).

update(current_time, Tb=24.0, Tr=0.0, **kwds)[source]

Update fields with current loading conditions.

Parameters:

current_time: float

Current time (years).

Tr: float, optional

Storm duration (hours).

Tb: float, optional

Inter-storm duration (hours).

assert_method_is_valid(method)[source]