Temperature formulas (Heat Overlay)
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Two temperature formulas are used in the calculation of the PET value:
Atmospheric Temperature formula
$ T_{a,t}=T_{station,t}+UHI_{max,t}\cdot f_{sun,t} $
where
- $ T_{a,t} $ is the calculated atmospheric temperature at time t;
- $ T_{station,t} $ is the temperature measured at a weather station at time t;
- $ UHI_{max,t} $ is the calculated Urban Heat Island effect at time t;
- $ f_{sun,t} $ is the sun daily motion factor at time t;
Wet-bulb Temperature formula
$ 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 $
where:
- $ T_{w,t} $ is the calculated wet-bulb temperature;
- $ T_{a,t} $ is the calculated atmospheric temperature;
- $ \phi $ is the sun altitude angle;
- Constant values are sourced from the DPRA Heat stress report;
See also
- ↑ Wikipedia • Wet-bulb temperature • https://en.wikipedia.org/wiki/Wet-bulb_temperature • Last visited: 20-12-2019
