The groundwater evapotranspiration (ET ) which is part of total evapotranspiration, represents two different processes and therefore consists of two different components, groundwater transpiration (T) and groundwater evaporation (E):
Groundwater transpiration (Tg) is defined by Lubczynski and Gurwin  and Lubczynski  as the root water uptake from groundwater or the capillary fringe while groundwater evaporation (Eg) as the liquid and/or vapor water loss from groundwater or the capillary fringe. The capillary fringe is indicated in both definitions because when linked with groundwater, its local loss, for example due to root water uptake or direct evaporation from water table, is replenished by water originated from the aquifer so such process occurs at the expense of groundwater. The ETg affects mainly dry, water limited environments during dry seasons when there is large potential evapotranspiration (PET) and large air vapor pressure deficit (VPD).
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