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A Simple Accurate Formula for Calculating Saturation Vapor Pressure of Water and Ice

American Meteorological Society
Journal of Applied Meteorology and Climatology
Authors:
Jianhua Huang
Jianhua Huang
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Abstract

It is necessary to calculate the saturation vapor pressure of water and of ice for some purposes in many disciplines. A number of formulas are available for this calculation. These formulas either are tedious or are not very accurate. In this study, a new formula has been developed by integrating the Clausius-Clapeyron equation. This new formula is simple and easy to remember. In comparison with the International Association for the Properties of Water and Steam reference dataset, the mean relative errors from this new formula are only 0.001% and 0.006% for the saturation vapor pressure of water and of ice, respectively, within a wide range of temperatures from -100° to 100°C. In addition, this new formula yields a mean relative error of 0.0005% within the commonly occurring temperature range (10°-40°C). Therefore, this new formula has significant advantages over the improved Magnus formula and can be used to calculate the saturation vapor pressure of water and of ice in a wide variety of disciplines.
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The saturation vapor pressure of water is calculated by an extremely accurate
formula:
 
 
57.1
1.237
99.4924
494.34
s105
P
t
et
(t > 0°C)
The saturation vapor pressure of ice is calculated by an extremely accurate
formula:
 
 
2
278
8.6545
494.43
s868
P
t
et
(t ≤ 0°C)
Reference:
Jianhua Huang, A simple accurate formula for calculating saturation vapor pressure of
water and ice, Journal of Applied Meteorology and Climatology, 2018, 57(6): 1265-
1272
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