Definitions

Question 1

Evaporation: E [mm/Δt]

Answer 1

Transformation from liquid water to water vapour from bare soils, plant surfaces and free water surfaces.

Question 2

Interception: EI [mm/Δt]

Answer 2

Part of precipitation, which is intercepted on plant surfaces (canopy) and evaporated without reaching the ground (part of evaporation).

Question 3

Transpiration: T [mm/Δt]

Answer 3

Evaporation of water from within plants through stomata resulting from plant metabolism.

Question 4

Evapotranspiration: ET [mm/Δt]

Answer 4

Sum of evaporation and transpiration, often related to an area or catchment.

Question 5

Potential Evapo(transpi)ration (ETP) in mm/Δt:

Answer 5

Maximal possible evaporation for an idealized water saturated surface under existing atmospheric conditions allowing to use all available energy for evaporation.

Question 6

Actual Evapo(transpi)ration (ETR) in mm/Δt :

Answer 6

Real occurring evaporation from a surface given actual water availability under existing atmospheric conditions.

ETR <= ETP