evapotranspiration: a standalone construct

Evapotranspiration is the combined loss of water to the atmosphere from evaporation of soil and open-water surfaces and transpiration through plants; it is a major term in the water and energy balance and is often the largest outflow from a catchment after precipitation. Thornthwaite's 1948 An approach toward a rational classification of climate introduced potential evapotranspiration as the water demand of a well-watered surface, while Penman's 1948 Natural evaporation from open water, bare soil and grass derived evaporation from combined energy-balance and aerodynamic principles. The referent is atmospheric water loss from vegetated and bare surfaces, split into potential (demand-limited) and actual (supply-limited) forms.[1][2]

Unit

Depth of water lost to the atmosphere per unit time (e.g. mm/day)

Recovery means

Not applicable

Measured by

Measured by lysimeters, eddy-covariance flux towers, or water balance, and estimated from climate data via the Penman-Monteith or Thornthwaite methods