Calculation of Open Water Evaporation as a Climate Parameter

Abstract

Calculation of open water evaporation is important for hydrology, industry, agriculture, environment, and other fields. The available methods of calculating evaporation are based on field or laboratory experiments and should not be used for scale-up to open water evaporation for similitude relationships cannot be correctly obtained. The methods are thus unjustified scientifically. In addition, surface evaporation is not a local phenomenon that is a function of independent meteorological parameters. These are in fact dependent parameters, and the solar energy exchanged with the surface of the earth is the only independent variable for open water evaporation. Contrary to the existing methods, meteorological records and measurements are therefore not required. Many parts of the world do not have full or partial records available. For these, the available methods are likely not to be useful. In addition, future meteorological records or measurements cannot be made available for evaporation projection in a warming world. This may well place a limit on using the existing methods. The work presented in this manuscript reveals a new understanding of evaporation as a climate parameter instead and can be calculated as such. Minimal to no meteorological records or measurements may be required. The advantages of the proposed method are scientific justification, simplicity, accuracy, versatility, low to virtually no cost, and can be used to map present and future evaporation in a short period of time.