HydPy-Evap-PET-HBV96 (potential evapotranspiration after HBV96)

The primary purpose of evap_pet_hbv96 is to serve as a submodel that provides estimates of potential evapotranspiration corresponding to HBV96 (Lindström et al., 1997). Of course, you can connect it to hland_96 if you want a close HBV96 emulation, but it also works with other main models like lland_dd or wland_wag.

evap_pet_hbv96 itself requires other models for determining temperature and precipitation. By default, it queries the already available data from its main model. Alternatively, it can handle its own submodels. The following tests rely on the latter option.

Integration test

Note

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

According to the intended usage as a submodel, evap_pet_hbv96 requires no connections to any nodes. Hence, assigning a model instance to a blank Element instance is sufficient:

>>> from hydpy import Element
>>> from hydpy.models.evap_pet_hbv96 import *
>>> parameterstep("1h")
>>> element = Element("element")
>>> element.model = model

We perform the integration test for a single simulation step, the first hour of the second day of the simulation period selected for the integration tests of hland_96:

>>> from hydpy import IntegrationTest, pub
>>> pub.timegrids = "2000-01-02 00:00", "2000-01-02 01:00", "1h"

We set all parameter values identical to the ones defined in the field example of hland_96:

>>> nmbhru(1)
>>> hruarea(1.0)
>>> hrualtitude(100.0)
>>> evapotranspirationfactor(0.7)
>>> airtemperaturefactor(0.1)
>>> altitudefactor(-0.1)
>>> precipitationfactor(0.1)

A meteo_temp_io submodel provides the required temperature, and a meteo_precip_io submodel the required precipitation:

>>> with model.add_tempmodel_v2("meteo_temp_io"):
...     temperatureaddend(0.0)
>>> with model.add_precipmodel_v2("meteo_precip_io"):
...     precipitationfactor(1.0)

Now we can initialise an IntegrationTest object:

>>> test = IntegrationTest(element)
>>> test.dateformat = "%d/%m %H:00"

The following meteorological input also stems from the input data of the field example:

>>> inputs.normalairtemperature.series = 18.2
>>> inputs.normalevapotranspiration.series = 0.097474
>>> model.tempmodel.sequences.inputs.temperature.series = 19.2

The following precipitation value is from the results table of the field example:

>>> model.precipmodel.sequences.inputs.precipitation.series = 0.847

The following simulation results contain the calculated reference and potential evapotranspiration. Reference evapotranspiration is not available in the results of the field example of hland_96. The potential evapotranspiration estimate is the same in both tables:

>>> test()
Click to see the table
|        date | normalairtemperature | normalevapotranspiration | meanairtemperature | precipitation | referenceevapotranspiration | potentialevapotranspiration | meanpotentialevapotranspiration |
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| 02/01 00:00 |                 18.2 |                 0.097474 |               19.2 |         0.847 |                    0.075055 |                     0.06896 |                         0.06896 |

class hydpy.models.evap_pet_hbv96.Model

Bases: Main_TempModel_V1, Main_TempModel_V2A, Main_PrecipModel_V1, Main_PrecipModel_V2A, Sub_ETModel, PETModel_V1

HydPy-Evap-PET-HBV96 (potential evapotranspiration after HBV96).

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

• Calc_MeanAirTemperature_V1 Let a submodel that complies with the TempModel_V1 or TempModel_V2 interface determine the air temperature.

• Calc_Precipitation_V1 Let a submodel that complies with the PrecipModel_V1 or PrecipModel_V2 interface determine precipitation.

• Calc_ReferenceEvapotranspiration_V5 Adjust the normal evapotranspiration to the difference between actual air temperature and normal air temperature (Lindström et al., 1997).

• Adjust_ReferenceEvapotranspiration_V1 Adjust the previously calculated reference evapotranspiration.

• Calc_PotentialEvapotranspiration_V3 Apply the altitude- and precipitation-related adjustment factors on reference evapotranspiration to determine potential evapotranspiration (Lindström et al., 1997).

• 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_MeanAirTemperature_TempModel_V1 Query mean air temperature from a main model referenced as a sub-submodel and follows the TempModel_V1 interface.

• Calc_MeanAirTemperature_TempModel_V2 Let a submodel that complies with the TempModel_V2 interface determine the mean air temperature.

• Calc_Precipitation_PrecipModel_V1 Query precipitation from a main model that is referenced as a sub-submodel and follows the PrecipModel_V1 interface.

• Calc_Precipitation_PrecipModel_V2 Let a submodel that complies with the PrecipModel_V2 interface determine the precipitation.

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

• TempModel_V1 Pure getter interface for using main models as sub-submodels.

• TempModel_V2 Simple interface for determining the temperature in one step.

• PrecipModel_V1 Pure getter interface for using main models as sub-submodels.

• PrecipModel_V2 Simple interface for determining precipitation in one step.

DOCNAME: DocName = ('Evap-PET-HBV96', 'potential evapotranspiration after HBV96')

tempmodel: SubmodelProperty

Required submodel that complies with one of the following interfaces: TempModel_V1 or TempModel_V2.

precipmodel: modeltools.SubmodelProperty

Required submodel that complies with one of the following interfaces: PrecipModel_V1 or PrecipModel_V2.

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

preparemethod2arguments: dict[str, tuple[tuple[Any, ...], dict[str, Any]]]

cymodel: CyModelProtocol | None

parameters: parametertools.Parameters

sequences: sequencetools.Sequences

masks: masktools.Masks

class hydpy.models.evap_pet_hbv96.ControlParameters(master: Parameters, cls_fastaccess: type[FastAccessParameter] | None = None, cymodel: CyModelProtocol | None = None)

Bases: SubParameters

Control parameters of model evap_pet_hbv96.

The following classes are selected:

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

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

• HRUAltitude() The altitude of each hydrological response unit [m].

• EvapotranspirationFactor() The adjustment factor for potential evapotranspiration [-].

• AltitudeFactor() Decrease of potential evapotranspiration with altitude [-1/100m].

• PrecipitationFactor() Decrease in potential evapotranspiration due to precipitation [T/mm].

• AirTemperatureFactor() Temperature factor related to the difference of current reference evapotranspiration and normal reference evapotranspiration [1/°C].

class hydpy.models.evap_pet_hbv96.DerivedParameters(master: Parameters, cls_fastaccess: type[FastAccessParameter] | None = None, cymodel: CyModelProtocol | None = None)

Bases: SubParameters

Derived parameters of model evap_pet_hbv96.

The following classes are selected:

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

• Altitude() Average (reference) subbasin altitude [100m].

class hydpy.models.evap_pet_hbv96.FactorSequences(master: Sequences, cls_fastaccess: type[TypeFastAccess_co] | None = None, cymodel: CyModelProtocol | None = None)

Bases: FactorSequences

Factor sequences of model evap_pet_hbv96.

The following classes are selected:

• MeanAirTemperature() The basin’s mean air temperature [°C].

class hydpy.models.evap_pet_hbv96.FluxSequences(master: Sequences, cls_fastaccess: type[TypeFastAccess_co] | None = None, cymodel: CyModelProtocol | None = None)

Bases: FluxSequences

Flux sequences of model evap_pet_hbv96.

The following classes are selected:

• Precipitation() Precipitation [mm/T].

• 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_hbv96.InputSequences(master: Sequences, cls_fastaccess: type[TypeFastAccess_co] | None = None, cymodel: CyModelProtocol | None = None)

Bases: InputSequences

Input sequences of model evap_pet_hbv96.

The following classes are selected:

• NormalAirTemperature() Normal air temperature [°C].

• NormalEvapotranspiration() Normal evapotranspiration [mm/T].