### Author Topic: Wet Bulb Globe Temperature  (Read 242 times)

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#### marshad

• Member
• Posts: 17
##### Wet Bulb Globe Temperature
« on: July 17, 2021, 08:35:19 AM »
Wet Bulb Globe Temperature (WBGT) is an important indicator of heat stress and is used by the military, sports and occupational health authorities. More info here: https://en.wikipedia.org/wiki/Wet-bulb_globe_temperature.

It needs a black globe thermometer to be measured accurately as it takes into account solar radiation, sun position and wind speed as well as temperature and humidity. I have tried to create a program in python to simulate WBGT using standard weather station data. The main source for the maths is here: https://www.weather.gov/media/tsa/pdf/WBGTpaper2.pdf. (I don't pretend to understand all the maths!)

Code: [Select]
`import mathfrom math import logfrom math import atanfrom math import expfrom math import cosfrom math import radians# Temperature in °C# Humidity in %# Pressure Sea Level in mbars# WindSpeed in Km/h# SolarRad in w/m3# SunAltitude in degrees above horizon# Cloudcover in %# Enter the dataTemperature = 29.7Humidity = 27Pressure = 1014WindSpeed = 0SolarRad = 780SunAltitude = 45Cloudcover = 0T = TemperatureRH = HumidityP = PressureW = WindSpeedS = SolarRadAlt = SunAltitudef = Cloudcoveru = W * 1000if u == 0:    u = 500z = radians(90 - Alt)a = 17.368b = 238.88g = log(RH/100) + ((a*T)/(b+T))# Calculate Dew Point DP DP = (b * g)/(a-g)# Calculate Wet Bulb WBWB = T * atan(0.151977 * (RH + 8.313659)**0.5) + atan(T + RH) - atan(RH - 1.676331) + 0.00391838 * RH**1.5 * atan(0.023101 * RH) - 4.686035ea = exp(17.67 * (DP - T)/(DP + 243.5)) * (1.0007 + 0.00000346 * P) * 6.112 * exp(17.502 * T / (240.97 + T))eb = 0.575 * ea**0.142857fdif = (100 - f)/100fdb = 1 - fdifB = S * ((fdb / ((4*(5.67*10**-8)) * cos(z))) + (1.2/(5.67*10**-8)) * fdif) + eb * T**4C = (0.315*u**0.58)/(5.3865*10**-8)# Calculate Globe Temperature GTGT = (B + C * T + 7680000)/(C+256000)# Calculate Wet Bulb Globe Temperature WBGTWBGT = 0.7*WB + 0.2*GT + 0.1*Tprint(round(WBGT, 2))`
Has anybody else tried to do this?
Does anybody have access to real WBGT data to test it?

The program is running live on my site using my own data (in the Temperature box)

http://moonappreciationsociety.com/Meteo/VillarPerosa/index.php

#### SteveFitz1

• Forecaster
• Posts: 448
##### Re: Wet Bulb Globe Temperature
« Reply #1 on: July 17, 2021, 08:55:56 AM »
I created a WBGT page on my site a couple of years ago using PHP. You can see my page here:
https://www.tylertexasweather.com/wbgtforecast.htm

I use a page on the NWS site to compare my results to. They are very close.
https://www.weather.gov/tsa/wbgt

Steve

#### marshad

• Member
• Posts: 17
##### Re: Wet Bulb Globe Temperature
« Reply #2 on: July 17, 2021, 12:37:33 PM »
Thanks Steve

What are you using to calculate WBGT?

Can you share the code?

#### SteveFitz1

• Forecaster
• Posts: 448
##### Re: Wet Bulb Globe Temperature
« Reply #3 on: July 18, 2021, 11:39:51 AM »
Check your messages. I sent you a couple of PMs.

Steve

#### marshad

• Member
• Posts: 17
##### Re: Wet Bulb Globe Temperature
« Reply #4 on: July 19, 2021, 07:55:20 AM »
Check your messages. I sent you a couple of PMs.

Steve

Thanks -have responded.

anything