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A review of global terrestrial evapotranspiration: Observation, modeling, climatology, and climatic variability
Author(s) -
Wang Kaicun,
Dickinson Robert E.
Publication year - 2012
Publication title -
reviews of geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 8.087
H-Index - 156
eISSN - 1944-9208
pISSN - 8755-1209
DOI - 10.1029/2011rg000373
Subject(s) - evapotranspiration , environmental science , latent heat , climatology , precipitation , bowen ratio , vegetation (pathology) , transpiration , land cover , water cycle , satellite , sensible heat , atmospheric sciences , meteorology , land use , geography , geology , medicine , ecology , photosynthesis , botany , civil engineering , pathology , aerospace engineering , engineering , biology
This review surveys the basic theories, observational methods, satellite algorithms, and land surface models for terrestrial evapotranspiration, E (or λE , i.e., latent heat flux), including a long‐term variability and trends perspective. The basic theories used to estimate E are the Monin‐Obukhov similarity theory (MOST), the Bowen ratio method, and the Penman‐Monteith equation. The latter two theoretical expressions combine MOST with surface energy balance. Estimates of E can differ substantially between these three approaches because of their use of different input data. Surface and satellite‐based measurement systems can provide accurate estimates of diurnal, daily, and annual variability of E . But their estimation of longer time variability is largely not established. A reasonable estimate of E as a global mean can be obtained from a surface water budget method, but its regional distribution is still rather uncertain. Current land surface models provide widely different ratios of the transpiration by vegetation to total E . This source of uncertainty therefore limits the capability of models to provide the sensitivities of E to precipitation deficits and land cover change.