Assessment of the Accuracy and Computing Speed of Simplified Saturation Vapor Equations Using a New Reference Dataset.

Abstract A revised saturation vapor dataset is proposed for use in meteorology. Based on new engineering data of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers for temperatures above 0°C, it should supersede the older Smithsonian and World Meteorological Organization meteorological tables. Simple new equations are proposed to compute the saturation vapor pressure over water between −50° and 50°C. Their accuracy is shown to be excellent over this range, with an nns error of 3 × 10−3 mb and an average relative error of 0.02%. Detailed statistics descrbing the accuracy performance of 22 other equations are presented and the speed performance of all these equations is assessed. Nested polynomials are shown to provide both good accuracy and computational speed. On a modern minicomputer, a single evaluation of saturation vapor pressure may take less than 1 µs of CPU time, 15 times less than required by the Goff–Gratch equations that were used to construct the meteorological tables.