Potential evaporation

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Potential evaporation or potential evapotranspiration (PET) is defined as the amount of evaporation that would occur if a sufficient water source were available. If the actual evapotranspiration is considered the net result of atmospheric demand for moisture from a surface and the ability of the surface to supply moisture, then PET is a measure of the demand side. Surface and air temperatures, insolation, and wind all affect this. A dryland is a place where annual potential evaporation exceeds annual precipitation.

Contents

[edit] Estimates of potential evaporation

[edit] Thornthwaite equation (1948)

PET = 16 \left(\frac{L}{12}\right)\left(\frac{N}{30}\right)\left(\frac{10\, T_a}{I}\right)^\alpha

Where,

\alpha = (6.75\times 10^{-7}) I^3 - (7.71 \times 10^{-5}) I^2 + (1.79 \times 10^{-2}) I + 0.49

I = \sum_{i=1}^{n} \left(\frac{T_{ai}}{5}\right)^{1.514}

[edit] Penman equation (1948)

[edit] See also

[edit] References

  • Thornwaite, C.W. (1948). "An approach towards a rational classification of climate". Geographical Review 38: 55-94. 
  • Penman, H.L. (1948). "Natural evaporation from open water, bare soil, and grass". Proc. Roy. Soc. A193: 120-145. 
  • Brutsaert, W.H. (1982). Evaporation into the Atmosphere: theory, history, and applications. Dortrecht, Holland: D. Reidel. ISBN 9027712476. 
  • Bonan, Gordon (2002). Ecological Climatology. Cambridge, U.K.: CUP. ISBN 978-0-521-80476-0. 

[edit] External links

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