Tetens equation

The Tetens equation is an equation to calculate the saturation vapour pressure of water over liquid and ice. It is named after its creator, O. Tetens who was an early German meteorologist. He published his equation in 1930, and while the publication itself is rather obscure, the equation is widely known among meteorologists and climatologists because of its ease of use and relative accuracy at temperatures within the normal ranges of natural weather conditions.

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