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

Abstract

[1] This review surveys the basic theories, observational methods, satellite algorithms, and land surface models for terrestrial evapotranspiration, E (or lE, 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.

Spatial variation in annual actual evapotranspiration of terrestrial ecosystems in China: Results from eddy covariance measurements

“…As we know, the physical ET process is influenced by various interconnected environmental and biological factors (Jarvis and McNaughton, 1986;Wilson and Baldocchi, 2000;Wang and Dickinson, 2012). Thus, the spatial variation in AET was supposed to be constrained by both climatic factors and vegetation attributes but maybe with different ways.…”

“…A number of in situ observation methods have been widely applied at ecosystem level (Shuttleworth, 2007;Shuttleworth, 2008;Wang and Dickinson, 2012), in which eddy covariance (EC) method can directly measure ET on a continuous and long-term basis Baldocchi, 2008;Zhu et al, 2012) and is preferred among meteorologists and ecologists. Currently, with EC as the main observation method, FLUXNET and several regional networks, including regional networks in Europe (CarboEuroflux), North America (Ameriflux) and China (ChinaFLUX) , have been operating for several years, which provide vital data sources for analyzing spatial variation in AET.…”

“…Evapotranspiration (ET) is the major component for both terrestrial water cycle and surface energy balance (Wang and Dickinson, 2012). Understanding the spatial variation in annual actual evapotranspiration (AET) and its influencing factors is not only crucial for predicting responses of large-scale hydrological processes to global climate change, but also essential for the water resources management (Allen et al, 1998;Dodds et al, 2005;Zhao and Zhao, 2014) and eco-environment researches such as desertification (Zhou et al, 2002) and droughts (McVicar and Jupp, 1998) under climate change.…”

Comparison of Methods for Estimating Reference Evapotranspiration: An Approach to the Management of Water Resources Within an Experimental Basin in the Brazilian Cerrado

“…It has significant hydrological, agricultural and ecological implications. This process uses nearly three-fifths of annual solar radiation, available globally towards the Earth's surface (WANG & DICKINSON, 2012). Moreover, it is a key element in water balance, so its estimate is of vital importance for water resources and for forecasting drought periods (LINGLING et al, 2013).…”

Construction and progress of Chinese terrestrial ecosystem carbon, nitrogen and water fluxes coordinated observation

“…Evapotranspiration (ET) is an important component of water cycle and energy balance in terrestrial ecosystems (Wang and Dickinson, 2012). Investigating the spatio-temporal variations of ET and their influencing factors is of great significance for water resource management and assessment (Zheng et al, 2016).…”