Methods of estimating crop evapotranspiration with remote sensing

Crop water use includes water that is used by plants and transpired through their leaves and into the air or evaporated from wet soil and leaves. Together, these processes that move water into the air as water vapor are referred to as evapotranspiration, or ET. ET is the main component of consumptive use, which is the water lost from the watershed as water vapor to support plant growth. New methods are emerging to estimate crop ET, which can better inform irrigation system design and management and help document beneficial use. To generate and appropriately use crop ET estimates, it is important to consider the balances of water and energy and include data on weather, soil conditions, and crop characteristics in a given field. This publication describes recent advances in methods to estimate crop ET and advances that broaden free access to these estimates to improve the ability to plan and track consumptive use.