A review of global terrestrial evapotranspiration: Observation, modeling, climatology, and climatic variability

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…