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Potential evapotranspiration (PET) or potential evaporation (PE) is the amount of water that would be evaporated and transpired by a specific crop, soil or ecosystem if there was sufficient water available. It is a reflection of the energy available to evaporate or transpire water, and of the wind available to transport the water vapor from the ...
Definition. Evapotranspiration is defined as: "The combined processes through which water is transferred to the atmosphere from open water and ice surfaces, bare soil and vegetation that make up the Earth’s surface." [2]: 2908. Evapotranspiration is a combination of evaporation and transpiration, measured in order to better understand crop ...
The Standardized Precipitation Evapotranspiration Index (SPEI) is a multiscalar drought index based on climatic data. It was developed by Vicente-Serrano et al. (2010) at the Institute Pirenaico de Ecologia in Zaragoza, Spain. [1] It can be used for determining the onset, duration and magnitude of drought conditions with respect to normal ...
The Penman-Monteith equation approximates net evapotranspiration (ET) from meteorological data as a replacement for direct measurement of evapotranspiration. The equation is widely used, and was derived by the United Nations Food and Agriculture Organization for modeling reference evapotranspiration ET 0.
Usage. The Blaney–Criddle equation is a relatively simplistic method for calculating evapotranspiration. When sufficient meteorological data is available the Penman–Monteith equation is usually preferred. However, the Blaney–Criddle equation is ideal when only air-temperature datasets are available for a site.
It uses meteorological data from the moment of the recording of the satellite data to solve the 'instantaneous' energy balance, and uses extrapolation to calculate daily evapotranspiration. Using a time series of satellite and meteorological data, periodic cumulative (e.g. weekly, monthly, yearly) evapotranspiration data can be calculated.
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The Penman equation describes evaporation (E) from an open water surface, and was developed by Howard Penman in 1948. Penman's equation requires daily mean temperature, wind speed, air pressure, and solar radiation to predict E. Simpler Hydrometeorological equations continue to be used where obtaining such data is impractical, to give comparable results within specific contexts, e.g. humid vs ...