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start:hype_model_description:processes_above_ground [2018/10/02 10:30] cpers [Input to alternative potential evaporation models] |
start:hype_model_description:processes_above_ground [2019/03/19 16:12] cpers [Evaporation] |
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|Figure 3 Soil temperature factor for reduction of soil evapotranspiration. Parameter values: //ttrip//=1, //tredA//=0.5, //tredB//=1.| | |Figure 3 Soil temperature factor for reduction of soil evapotranspiration. Parameter values: //ttrip//=1, //tredA//=0.5, //tredB//=1.| | ||
- | The actual evaporation is set to zero for temperatures below the threshold temperature and for negative potential evaporation estimates (condensation). The soil evapotranspiration reduction is calculated as: | + | The soil temperature evapotranspiration reduction is calculated as: |
<m> factor = 1-e^( - tredA*(soiltemp-ttrig)^tredB) </m> | <m> factor = 1-e^( - tredA*(soiltemp-ttrig)^tredB) </m> | ||
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<m> evapp = evapp*factor </m> | <m> evapp = evapp*factor </m> | ||
- | A river with an area (is a class), flooded floodplains and lakes are assumed to evaporate at the potential rate, when the air temperature is above the threshold temperature (//ttmp//). Evaporation is limited by the water body's volume. | + | The actual soil evaporation is set to zero for temperatures below the threshold temperature and for negative potential evaporation estimates (condensation). |
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+ | A river with an area (i.e. is a class), flooded floodplains and lakes are assumed to evaporate at the potential rate, when the air temperature is above the threshold temperature (//ttmp//). Evaporation is limited by the water body's volume. | ||
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HYPE give the option to exchange the default potential evaporation model for another model. Only the basic potential evaporation (<m>epot_base</m>) differs between models. Models 0-2 only use air temperature forcing. Models 3-5 want shortwave radiation and minimum and maximum daily air temperature, although if lacking approximations are made (see section [[start:hype_model_description:processes_above_ground#input_to_alternative_potential_evaporation_models|Input to alternative potential evaporation models]] below). In addition, model 5 wants relative humidity and wind speed if available. | HYPE give the option to exchange the default potential evaporation model for another model. Only the basic potential evaporation (<m>epot_base</m>) differs between models. Models 0-2 only use air temperature forcing. Models 3-5 want shortwave radiation and minimum and maximum daily air temperature, although if lacking approximations are made (see section [[start:hype_model_description:processes_above_ground#input_to_alternative_potential_evaporation_models|Input to alternative potential evaporation models]] below). In addition, model 5 wants relative humidity and wind speed if available. | ||
+ | Note, regardless of potential evaporation model, the actual evaporation is limited to temperatures above parameter //ttmp//. | ||
=== Model 0 (default) === | === Model 0 (default) === |