Dew Point Calculation

[Clare Rodenberg]

Hello All,

I have been trying to calculate dew point with the program provided on the SWAT website dew02.exe

Unfortunately the program does not seem to be working. My input file is in the correct format and has all of the necessary information.

Does anyone know of an alternative for calculating dew point (either a program, or a calculation?)

Thank you in advance,
Clare

[Kyle]

Clare,

I assume you have temperature and relative humidity, correct?  If so, you can find some information at this link: http://iridl.ldeo.columbia.edu/dochelp/QA/Basic/dewpoint.html

The simple equation you can take from this text is copied below.

Cheers,

Kyle

If you are interested in a simpler calculation that gives an approximation of dew point temperature if you know the observed temperature and relative humidity, the following formula was proposed in a 2005 article by Mark G. Lawrence in the Bulletin of the American Meteorological Society:

Td = T - ((100 - RH)/5.)

where Td is dew point temperature (in degrees Celsius), T is observed temperature (in degrees Celsius), and RH is relative humidity (in percent). Apparently this relationship is fairly accurate for relative humidity values above 50%.

More details can be found in the article:

Lawrence, Mark G., 2005: The relationship between relative humidity and the dewpoint temperature in moist air: A simple conversion and applications. Bull. Amer. Meteor. Soc., 86, 225-233. doi: http;//dx.doi.org/10.1175/BAMS-86-2-225