Relative Humidity and Dewpoint Temperature from Temperature
and WetBulb Temperature
Note: This calculation is very complex and requires a knowledge of algebra.
From the user, an air temperature ,
a wetbulb temperature ,
and a station pressure
are given. The temperature values must be converted to units of degrees Celsius
.
Also, the station pressure must be converted to units of millibar
or hectoPascal .
To see how to convert temperatures and pressures, see the links below:
tempConvert.php
pressureConversion.php
Then, an actual vapor pressure needs to be calculated. To accomplish the calculation,
a vapor pressure related to wetbulb temperature
and a saturated vapor pressure
must be calculated first using the equations below:
where
is the number .
Then, an actual vapor pressure
can be calculated using the equation below:
Finally, a relative humidity
and a dewpoint temperature
can be calculated using the equations below:
where
is the actual vapor pressure.
