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Evapotranspiration is water loss from soil/water bodies and plants. It's critical for irrigation design, water balance, and climate analysis.
Steg-för-steg-guide
- 1Reference ET (ET₀): well-watered grass, calculated from temperature, humidity, wind, radiation
- 2Actual ET: ET₀ × crop coefficient (varies 0.2-1.2 by crop)
- 3Typical: 100-200 mm/month depending on climate
Lösta exempel
Ingång
ET₀ = 5 mm/day, alfalfa (K_c = 1.0)
Resultat
Daily ET = 5 mm, weekly = 35 mm (irrigation need)
During growing season
Vanliga misstag att undvika
- ✕Using ET₀ without crop coefficient (over-irrigating)
- ✕Neglecting seasonal variation (summer ET much higher)
Vanliga frågor
Why does crop type matter?
Deep-rooted crops (alfalfa) use more water; shallow (lettuce) less. Reflectance and canopy architecture differ.
How do you measure ET?
Lysimeters (soil columns), energy balance models, or empirical equations from climate data.
Redo att beräkna? Prova den kostnadsfria Evapotranspiration-kalkylatorn
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