*3.1.2 Temperature*

*Advanced Evapotranspiration Methods and Applications*

evapotranspiration − actual evapotranspiration.

*Schematic representation of the ETo and ETp (adapted from [16, 18]).*

**3. Factors affecting evapotranspiration (ET)**

**3.1 Climatic factors that affecting ET**

**2.3 Oasis evapotranspiration (ETo)**

**2.4 Evapotranspiration (ETc)**

spheric demand [17].

**Figure 2.**

*3.1.1 Radiation*

of E and T [17]. There is a relation between potential ET and actual ET. Crop water need can be estimated by the following equation: Crop water needs = potential

Oasis ET is the amount of water consumed by a small irrigated vegetation which is encircled by a widespread dry-area, at which dynamism of water to vapor is come from high temperature in combination with drought [16, 18]. **Figure 2** shows the border area necessary for minimizing the lateral transport of energy from the dry to the wet area (irrigated). At such an area, the ET that will take place is the oasis ET.

Evapotranspiration is the process by which an amount of water is used by any growth stage of a crop from sowing to harvest, at whatever time there is no water constraint in the soil [13, 16]. ETc is a function of leaf area (transpiring surface), because the bigger the leaf area (LAI), the higher ETc will be for the same atmo-

Weather parameters, crop characteristics, management and environmental aspects are factors affecting E, T, and ET. Details of these factors are as follows:

Radiation is the main source of energy for the ET process. It depends on the global solar radiation flux density and vegetation albedo. A darker vegetation

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Over the course of a day, an increase of the air temperature causes an increase on the saturation deficit triggering a higher evaporative demand in the air, and leading to high ET rates [13, 16].
