HydPy-Evap-PET-M-LC (month-based land cover adjustment of reference evapotranspiration)¶

Use evap_pet_mlc as a plug-in between a main model like lland_dd and another submodel like evap_ret_tw2002 to adjust the reference evapotranspiration given by evap_ret_tw2002 by month and land cover.

Integration tests¶

Note

When new to HydPy, consider reading section Integration Tests first.

Application model evap_pet_mlc does not define any land cover types by itself but takes the ones of the respective main model. Here, we manually introduce the land cover types of grass, trees, and water to apply evap_pet_mlc as a stand-alone model:

>>> from hydpy.core.parametertools import Constants
>>> GRASS, TREES, WATER = 0, 1, 2
>>> constants = Constants(GRASS=GRASS, TREES=TREES, WATER=WATER)
>>> from hydpy.models.evap.evap_control import HRUType, LandMonthFactor
>>> with HRUType.modify_constants(constants), LandMonthFactor.modify_rows(constants):
...     from hydpy.models.evap_pet_mlc import *
...     parameterstep()

Application model evap_pet_mlc requires no input from another model and does not supply any outlet sequence. Hence, assigning a model instance to a blank Element instance is sufficient:

>>> from hydpy import Element
>>> element = Element("element")
>>> element.model = model

In our simple test-setting, the submodel of type evap_ret_io supplies different reference evapotranspiration values for two hydrological response units of type “trees” and “water” for the last of January and the first of February 2000. evap_pet_mlc applies individual adjustment factors for both months and land cover types and “damps” the second unit’s result value:

>>> from hydpy import pub
>>> pub.timegrids = "2000-01-31", "2000-02-02", "1d"
>>> nmbhru(2)
>>> hrutype(TREES, WATER)
>>> hruarea(0.2, 0.8)
>>> landmonthfactor.trees_jan = 1.2
>>> landmonthfactor.trees_feb = 1.4
>>> landmonthfactor.water_jan = 1.6
>>> landmonthfactor.water_feb = 1.8
>>> dampingfactor(1.0, 0.5)
>>> with model.add_retmodel_v1("evap_ret_io"):
...     evapotranspirationfactor(0.8, 1.2)
>>>
>>> from hydpy import IntegrationTest
>>> test = IntegrationTest(element)
>>> test.dateformat = "%Y-%d-%m"
>>> test.inits = ((model.sequences.logs.loggedpotentialevapotranspiration, 1.92),)
>>>
>>> model.retmodel.sequences.inputs.referenceevapotranspiration.series = 1.0, 2.0

>>> test()Click to see the table
|       date |      referenceevapotranspiration |       potentialevapotranspiration | meanpotentialevapotranspiration |
-----------------------------------------------------------------------------------------------------------------------
| 2000-31-01 | 0.8                          1.2 | 0.96                         1.92 |                           1.728 |
| 2000-01-02 | 1.6                          2.4 | 2.24                         3.12 |                           2.944 |

Method features¶

class hydpy.models.evap_pet_mlc.Model[source]¶

Bases: Main_RET_PETModel_V1, Sub_ETModel, PETModel_V1

HydPy-Evap-PET-M-LC (month-based land cover adjustment of reference evapotranspiration).

The following “run methods” are called in the given sequence during each simulation step:

Calc_ReferenceEvapotranspiration_V4 Let a submodel that complies with the PETModel_V1 interface calculate the reference evapotranspiration.
Calc_PotentialEvapotranspiration_V2 Calculate month- and land cover-specific potential evaporation based on reference evapotranspiration.
Update_PotentialEvapotranspiration_V1 Damp the given potential evapotranspiration and update the corresponding log sequence.
Calc_MeanPotentialEvapotranspiration_V1 Calculate the average potential evapotranspiration.

The following interface methods are available to main models using the defined model as a submodel:

Determine_PotentialEvapotranspiration_V1 Interface method that applies the complete application model by executing all “run methods”.
Get_PotentialEvapotranspiration_V2 Get the current potential evapotranspiration from the selected hydrological response unit.
Get_MeanPotentialEvapotranspiration_V2 Get the averaged potential evapotranspiration.

The following “additional methods” might be called by one or more of the other methods or are meant to be directly called by the user:

Calc_ReferenceEvapotranspiration_PETModel_V1 Let a submodel that complies with the PETModel_V1 interface calculate the reference evapotranspiration.

Users can hook submodels into the defined main model if they satisfy one of the following interfaces:

PETModel_V1 Simple interface for calculating all potential evapotranspiration values in one step.

DOCNAME = ('Evap-PET-M-LC', 'month-based land cover adjustment of reference evapotranspiration')¶

retmodel¶: Required submodel that complies with the following interface: PETModel_V1.

REUSABLE_METHODS = ()¶