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Relative humidity formula
Does anyone have a formula for calculating relative humidity using
temperature and dew-point as input data? I have a large number of these calculations to do and using Excel is a much more attractive proposition than using look-up tables. Norman (delete "thisbit" twice to e-mail) -- Norman Lynagh Weather Consultancy Chalfont St Giles England |
Relative humidity formula
================================================== ================== This posting expresses the personal view and opinions of the author. Something which everyone on this planet should be able to do. ================================================== ================== Norman, I use Teten's formula in my excel spreadsheets to derive dewpoint from T/RH http://www.paroscientific.com/dewpoint.htm You'll have to a little bit of schoolboy maths to transpose the equation to get RH from T/Td ! Will. -- " A cup is most useful when empty " ------------------------------------------------------------------------------- A COL BH site in East Dartmoor at Haytor, Devon 310m asl (1017 feet). mailto: www: http://www.lyneside.demon.co.uk DISCLAIMER - All views and opinions expressed by myself are personal and do not necessarily represent those of my employer. ------------------------------------------------------------------------------- Norman Lynagh wrote in message ... Does anyone have a formula for calculating relative humidity using temperature and dew-point as input data? I have a large number of these calculations to do and using Excel is a much more attractive proposition than using look-up tables. Norman (delete "thisbit" twice to e-mail) -- Norman Lynagh Weather Consultancy Chalfont St Giles England |
Relative humidity formula
In message , Will
writes ================================================= =================== This posting expresses the personal view and opinions of the author. Something which everyone on this planet should be able to do. ================================================= =================== Norman, I use Teten's formula in my excel spreadsheets to derive dewpoint from T/RH http://www.paroscientific.com/dewpoint.htm You'll have to a little bit of schoolboy maths to transpose the equation to get RH from T/Td ! Will. Many thanks, Will. That takes me part of the way but it doesn't cope with dew points below 0c. Many of the values I am dealing with are below 0c. Norman. (delete "thisbit" twice to e-mail) -- Norman Lynagh Weather Consultancy Chalfont St Giles England |
Relative humidity formula
Norman Lynagh wrote in message ... In message , Will writes ================================================ ==================== This posting expresses the personal view and opinions of the author. Something which everyone on this planet should be able to do. ================================================ ==================== Norman, I use Teten's formula in my excel spreadsheets to derive dewpoint from T/RH http://www.paroscientific.com/dewpoint.htm You'll have to a little bit of schoolboy maths to transpose the equation to get RH from T/Td ! Will. Many thanks, Will. That takes me part of the way but it doesn't cope with dew points below 0c. Many of the values I am dealing with are below 0c. Norman. (delete "thisbit" twice to e-mail) -- OK Norman. back to basics. If you want high accuracy for -35 to +35 C use our old friend Clausius Clapeyron for calculating saturated and vapour pressu Es = 0.6112 x exp(17.67T/(T+243.5)) T in deg C E = 0.6112 x exp(17.67Td/(Td+243.5)) Td in deg C RH = E/Es Will. -- " A cup is most useful when empty " ------------------------------------------------------------------------------- A COL BH site in East Dartmoor at Haytor, Devon 310m asl (1017 feet). mailto: www: http://www.lyneside.demon.co.uk DISCLAIMER - All views and opinions expressed by myself are personal and do not necessarily represent those of my employer. ------------------------------------------------------------------------------- |
Relative humidity formula
In message , Will
writes Norman Lynagh wrote in message ... In message , Will writes =============================================== ===================== This posting expresses the personal view and opinions of the author. Something which everyone on this planet should be able to do. =============================================== ===================== Norman, I use Teten's formula in my excel spreadsheets to derive dewpoint from T/RH http://www.paroscientific.com/dewpoint.htm You'll have to a little bit of schoolboy maths to transpose the equation to get RH from T/Td ! Will. Many thanks, Will. That takes me part of the way but it doesn't cope with dew points below 0c. Many of the values I am dealing with are below 0c. Norman. (delete "thisbit" twice to e-mail) -- OK Norman. back to basics. If you want high accuracy for -35 to +35 C use our old friend Clausius Clapeyron for calculating saturated and vapour pressu Es = 0.6112 x exp(17.67T/(T+243.5)) T in deg C E = 0.6112 x exp(17.67Td/(Td+243.5)) Td in deg C RH = E/Es Will. Excellent, Will. Many thanks. Norman. (delete "thisbit" twice to e-mail) -- Norman Lynagh Weather Consultancy Chalfont St Giles England |
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