Meteotemplate Forum

Hi!
I have the wrong value in wetbulb in current condition block.


Temperature
1.9°C
Apparent temperature
-5.2°C
Dew point
0.4°C
Heat index
--°C
Humidex
-0.2
Windchill
-3.7°C
Wet-bulb
7.5°C

http://regnskvett.com/meteotemplate/indexDesktop.php

Hi,
same problem...
Temperature -2.4°C
Apparent temperature -6.0°C
Dew point -13.1°C
Heat index --°C
Humidex -6.7
Windchill -- °C
Wet-bulb 3.5°C

This one is problematic, it was not easy to find the right equation, this is the one used see if you can find any alternative one or the mistake in this one:

function getWB($WB_T,$WB_H){
global $displayTempUnits;
$e = $WB_H / 100 * 6.105 * exp(17.27 * $WB_T / (237.7 + $WB_T));
$WB = 0.567 * $WB_T + 0.393 * $e + 3.94;
$WB = convertor($WB,"C",$displayTempUnits);
return number_format($WB,1,".","");
}

Well, clearly something is indeed wrong with that formulation since wet-bulb temperature must lie between dew point and air temperature. The formula you have doesn't guarantee that. How about using this glorious mess?

Wetbulb is still a mess... the formula must be wrong it’s way to high!
If I use a calculator it should be -0.2°C not +6.3°C like mentioned by the template...

www.wetter-koblenz.com

Try:

function getWB($WB_T,$WB_H){
global $displayTempUnits;
$e = atan($WB_T + $WB_H) - atan($WB_H - 1.676331) + 0.00391838 * ($WB_H)**(3/2) * atan(0.023101 * $WB_H) - 4.686035;
$WB = $WB_T * atan(0.151977 * ($WB_H + 8.313659)**(1/2)) + $e;
$WB = convertor($WB,"C",$displayTempUnits);
return number_format($WB,1,".","");
}