Temperature formulas (Heat Overlay): Difference between revisions

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Two temperature formulas are used in the calculation of the PET value:
Two temperature formulas are used in the calculation of the PET value:
* The atmospheric temperature [[#Atmospheric Temperature formula|T<sub>a</sub>]]
* The atmospheric temperature [[#Atmospheric Temperature formula|T<sub>a</sub>]]
* The wet-bulb temperatur [[#Wet-bulb Temperature formula|T<sub>w</sub>]]
* The wet-bulb temperature<ref name="bulb" /> [[#Wet-bulb Temperature formula|T<sub>w</sub>]]


==Atmospheric Temperature formula==
==Atmospheric Temperature formula==
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==Wet-bulb Temperature formula==
==Wet-bulb Temperature formula==
<math>T_{w,t} = T_{a,t} \cdot \arctan{ 0.151977 \cdot \sqrt{\phi + 8.313659}} + \arctan {T_{a} + \phi} - \arctan{\phi - 1.676331} + 0.00391838 · \phi^{\frac{3}{2}} \arctan{0.023101 \cdot \phi} - 4.686935</math>
<math>T_{w,t} = T_{a,t} \cdot \arctan( 0.151977 \cdot \sqrt{\phi + 8.313659})+ \arctan (T_{a} + \phi) - \arctan(\phi - 1.676331) + 0.00391838 \cdot \phi^{\frac{3}{2}} \arctan(0.023101 \cdot \phi) - 4.686935</math>
 
where:
where:
* T<sub>w,t</sub> is the calculated wet-bulb temperature;
* <math>T_{w,t}</math> is the calculated wet-bulb temperature;
* T<sub>a,t</sub> is the calculated atmospheric temperature;
* <math>T_{a,t}</math> is the calculated atmospheric temperature;
* ϕ is the [[Sun_altitude_(Heat_Overlay)|sun altitude angle]];
* <math>\phi</math> is the [[Sun_altitude_(Heat_Overlay)|sun altitude angle]];
* Constant values are sourced from the {{Heat DPRA Report}};


==See also==
==See also==
* [https://en.wikipedia.org/wiki/Wet-bulb_temperature Wet-bulb temperature]
<references>
<ref name="bulb">Wikipedia • Wet-bulb temperature • https://en.wikipedia.org/wiki/Wet-bulb_temperature • Last visited: 20-12-2019</ref>
</references>
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{{Template:HeatOverlay_formula_nav}}

Latest revision as of 11:53, 13 September 2021

Two temperature formulas are used in the calculation of the PET value:

  • The atmospheric temperature Ta
  • The wet-bulb temperature[1] Tw

Atmospheric Temperature formula

where

  • is the calculated atmospheric temperature at time t;
  • is the temperature measured at a weather station at time t;
  • is the calculated Urban Heat Island effect at time t;
  • is the sun daily motion factor at time t;

Wet-bulb Temperature formula

where:

  • is the calculated wet-bulb temperature;
  • is the calculated atmospheric temperature;
  • is the sun altitude angle;
  • Constant values are sourced from the DPRA Heat stress report;

See also

  1. Wikipedia • Wet-bulb temperature • https://en.wikipedia.org/wiki/Wet-bulb_temperature • Last visited: 20-12-2019