The isotopic composition of evaporating waters - review of the historical evolution leading up to the Craig-Gordon model.

Attempts to explain the variations in the abundance of heavy isotopic species of water throughout the hydrologic cycle solely by means of the classical equilibrium-fractionation processes could not be reconciled with measured abundances of the isotopic species in residues of "evaporation systems". Focusing on the evaporation of surface waters, the paper follows the evolution of the concepts during the 1950-ties and early 1960-ties leading up to the formulation of the Craig-Gordan Evaporation Model in 1965.