wetbulp

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Torjan
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wetbulp

Post by Torjan » Sat Dec 09, 2017 11:42 am

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

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MarTM
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Re: wetbulp

Post by MarTM » Sat Dec 09, 2017 8:43 pm

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

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Jachym
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Re: wetbulp

Post by Jachym » Sun Dec 10, 2017 1:28 pm

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,".","");
}

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Re: wetbulp

Post by wx_jon » Mon Dec 11, 2017 7:04 pm

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?

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Re: wet-bulb

Post by WSKO_Karlchen » Sat Apr 13, 2019 9:15 pm

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...

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Wetterservice Koblenz

mitmas
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Re: wetbulp

Post by mitmas » Tue Jun 01, 2021 4:57 pm

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,".","");
}

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