Abstract:

Evapotranspiration is an important component of water balance including evaporation and plant transpiration. About 60% of precipitation was transported back to atmosphere by evapotranspiration every year. In this paper, the historical development of study methods which involve the Greek and Roman period, the initial measurements and experimentation period in 17^th century and the foundation period of present theories in 19^th century are presented. Several traditional approaches to estimate evapotranspiration are critically assessed, including hydrological, micrometeorological, plant physiological, analytical model and empirical methods. The new theories of scintillometer and remote sensing technology used in evapotranspiration study are introduced, its applicability and constraints are discussed as well. Finally, future development and perspectives of evapotranspiration study are explored.

Key words: evapotranspiration, theory and method, advance and future development