HydPy-Evap-PET-M (month-based adjustment of reference evapotranspiration)

Use evap_pet_m 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.

Integration tests

Note

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

Application model evap_pet_m 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.models.evap_pet_m import *
>>> parameterstep("1d")
>>> 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 for the last of January and the first of February 2000. evap_pet_m applies individual adjustment factors for both months and “damps” the second unit’s result value:

>>> from hydpy import pub
>>> pub.timegrids = "2000-01-31", "2000-02-02", "1d"
>>> nmbhru(2)
>>> hruarea(0.2, 0.8)
>>> monthfactor.jan = 0.5
>>> monthfactor.feb = 2.0
>>> 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, 0.6),)
>>>
>>> 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 | 0.4                          0.6 |                            0.56 |
| 2000-01-02 | 1.6                          2.4 | 3.2                          2.7 |                             2.8 |

class hydpy.models.evap_pet_m.Model

Bases: Main_RET_PETModel_V1, Sub_ETModel, PETModel_V1

HydPy-Evap-PET-M (month-based 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_V1 Calculate month-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: DocName = ('Evap-PET-M', 'month-based adjustment of reference evapotranspiration')

retmodel: SubmodelProperty

Required submodel that complies with the following interface: PETModel_V1.

REUSABLE_METHODS: ClassVar[tuple[type[ReusableMethod], ...]] = ()

cymodel: CyModelProtocol | None

parameters: parametertools.Parameters

sequences: sequencetools.Sequences

masks: masktools.Masks

class hydpy.models.evap_pet_m.ControlParameters(master: Parameters, cls_fastaccess: type[FastAccessParameter] | None = None, cymodel: CyModelProtocol | None = None)

Bases: SubParameters

Control parameters of model evap_pet_m.

The following classes are selected:

• NmbHRU() The number of separately modelled hydrological response units [-].

• HRUArea() The area of each hydrological response unit [km²].

• MonthFactor() Factor for converting general potential evaporation or evapotranspiration (usually grass reference evapotranspiration) to month-specific potential evaporation or evapotranspiration [-].

• DampingFactor() Damping factor (temporal weighting factor) for potential evapotranspiration [-].

class hydpy.models.evap_pet_m.DerivedParameters(master: Parameters, cls_fastaccess: type[FastAccessParameter] | None = None, cymodel: CyModelProtocol | None = None)

Bases: SubParameters

Derived parameters of model evap_pet_m.

The following classes are selected:

• MOY() References the “global” month of the year index array [-].

• HRUAreaFraction() The area fraction of each hydrological response unit [-].

class hydpy.models.evap_pet_m.FluxSequences(master: Sequences, cls_fastaccess: type[TypeFastAccess_co] | None = None, cymodel: CyModelProtocol | None = None)

Bases: FluxSequences

Flux sequences of model evap_pet_m.

The following classes are selected:

• ReferenceEvapotranspiration() Reference (grass) evapotranspiration [mm/T].

• PotentialEvapotranspiration() Potential (land type-specific) evapotranspiration [mm/T].

• MeanPotentialEvapotranspiration() Mean potential evapotranspiration [mm/T].

class hydpy.models.evap_pet_m.LogSequences(master: Sequences, cls_fastaccess: type[TypeFastAccess_co] | None = None, cymodel: CyModelProtocol | None = None)

Bases: LogSequences

Log sequences of model evap_pet_m.

The following classes are selected:

• LoggedPotentialEvapotranspiration() Logged (damped) potential evapotranspiration [mm/T].