Temperature formulas (Heat Stress Overlay): Difference between revisions

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Latest revision as of 06:56, 13 October 2026

Two temperature formulas are used in the calculation of the PET value and both are calculated per timeframe:

The atmospheric temperature $T_{a, t}$
The wet-bulb temperature^[1] $T_{w, t}$

Atmospheric Temperature formula

$T_{a, t} = T_{s t a t i o n, t} + U H I_{m a x, t} \cdot f_{s u n, t}$

where

$T_{a, t}$ is the calculated atmospheric temperature at time t;
$T_{s t a t i o n, t}$ is the temperature measured at a weather station at time t;
$U H I_{m a x, t}$ is the calculated Urban Heat Island effect at time t;
$f_{s u n, t}$ is the sun daily motion factor at time t;

Wet-bulb Temperature formula

$T_{w, t} = T_{a, t} \cdot \arctan (0.151977 \cdot \sqrt{ϕ_{t} + 8.313659}) + \arctan (T_{a, t} + ϕ_{t}) - \arctan (ϕ_{t} - 1.676331) + (0.00391838 \cdot ϕ_{t})^{\frac{3}{2}} \cdot \arctan (0.023101 \cdot ϕ_{t}) - 4.686935$

where:

$T_{w, t}$ is the calculated wet-bulb temperature;
$T_{a, t}$ is the calculated atmospheric temperature;
$ϕ_{t}$ is the relative humidity
Constant values are sourced from the DPRA Heat stress report;

@@ Line 1: / Line 1: @@
+Two temperature formulas are used in the calculation of the PET value and both are calculated per timeframe:
+* The atmospheric temperature [[#Atmospheric Temperature formula|<math>T_{a,t}</math>]]
+* The wet-bulb temperature<ref name="bulb" /> [[#Wet-bulb Temperature formula|<math>T_{w,t}</math>]]
 ==Atmospheric Temperature formula==
-T<sub>a,t</sub> = T<sub>station,t</sub> + UHI<sub>max,t</sub> * f<sub>sun,t<sub><br>
+<math>T_{a,t} = T_{station,t} + UHI_{max,t} \cdot f_{sun,t}</math>
-where,
-* T<sub>a<sub> is the calculated [[Temperature_atmosphere_result_type_(Heat_Overlay)|atmospheric temperature]] at time t;
+where
-* T<sub>station,t</sub> is the temperature measured at a weather station at time t;
+* <math>T_{a,t}</math> is the calculated [[Temperature_atmosphere_result_type_(Heat Stress Overlay)|atmospheric temperature]] at time t;
-* UHI<sub>max,t</sub> is the calculated [[UHI_formula_(Heat_Overlay)|Urban Heat Island]] effect at time t;
+* <math>T_{station,t}</math> is the [[Hourly_temperature_(Heat Stress Overlay)|temperature]] measured at a weather station at time t;
-* f<sub>sun<sub>[h] is the sun daily motion factor at time t;
+* <math>UHI_{max,t}</math> is the calculated [[UHI_formula_(Heat Stress Overlay)|Urban Heat Island]] effect at time t;
+* <math>f_{sun,t}</math> is the [[Sun_daily_motion_(Heat Stress Overlay)|sun daily motion factor]] at time t;
+==Wet-bulb Temperature formula==
+<math>T_{w,t} = T_{a,t} \cdot \arctan( 0.151977 \cdot \sqrt{\phi_t + 8.313659})+ \arctan (T_{a,t} + \phi_t) - \arctan(\phi_t - 1.676331) + (0.00391838 \cdot \phi_t)^{\frac{3}{2}} \cdot \arctan(0.023101 \cdot \phi_t) - 4.686935</math>
+where:
+* <math>T_{w,t}</math> is the calculated wet-bulb temperature;
+* <math>T_{a,t}</math> is the calculated atmospheric temperature;
+* <math>\phi_t</math> is the [[Hourly_humidity_(Heat Stress Overlay)|relative humidity]]
+* Constant values are sourced from the {{Heat DPRA Report}};
+==See also==
+<references>
+<ref name="bulb">Wikipedia • Wet-bulb temperature • https://en.wikipedia.org/wiki/Wet-bulb_temperature • Last visited: 20-12-2019</ref>
+</references>
+{{Template:HeatOverlay_formula_nav}}

Temperature formulas (Heat Stress Overlay): Difference between revisions

Latest revision as of 06:56, 13 October 2026

Atmospheric Temperature formula

Wet-bulb Temperature formula

See also

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