Temperature formulas (Heat Overlay): Difference between revisions

Latest revision as of 11:53, 13 September 2021

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

The atmospheric temperature T_a
The wet-bulb temperature^[1] T_w

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;

@@ Line 1: / Line 1: @@
 Two temperature formulas are used in the calculation of the PET value:
-* The atmospheric temperature T<sub>a</sub>
+* The atmospheric temperature [[#Atmospheric Temperature formula|T<sub>a</sub>]]
-* The wet-bulb temperatur T<sub>w</sub>
+* The wet-bulb temperature<ref name="bulb" /> [[#Wet-bulb Temperature formula|T<sub>w</sub>]]
 ==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,t</sub> is the calculated [[Temperature_atmosphere_result_type_(Heat_Overlay)|atmospheric temperature]] at time t;
+where
-* T<sub>station,t</sub> is the [[Hourly_temperature_(Heat_Overlay)|temperature]] measured at a weather station at time t;
+* <math>T_{a,t}</math> is the calculated [[Temperature_atmosphere_result_type_(Heat_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_Overlay)|temperature]] measured at a weather station at time t;
-* f<sub>sun,t</sub> is the [[Sun_daily_motion_(Heat_Overlay)|sun daily motion factor]] at time t;
+* <math>UHI_{max,t}</math> is the calculated [[UHI_formula_(Heat_Overlay)|Urban Heat Island]] effect at time t;
+* <math>f_{sun,t}</math> is the [[Sun_daily_motion_(Heat_Overlay)|sun daily motion factor]] at time t;
 ==Wet-bulb Temperature formula==
-T<sub>w</sub> = T<sub>a</sub> · atan( 0.151977 · (ϕ + 8.313659)<sup>0.5</sup>) + atan (T<sub>a</sub> + ϕ) - atan(ϕ - 1.676331) + 0.00391838 · ϕ<sup>3/2</sup> atan(0.023101 · ϕ) - 4.686935<br>
+<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:
+* <math>T_{w,t}</math> is the calculated wet-bulb temperature;
+* <math>T_{a,t}</math> is the calculated atmospheric temperature;
+* <math>\phi</math> is the [[Sun_altitude_(Heat_Overlay)|sun altitude angle]];
+* Constant values are sourced from the {{Heat DPRA Report}};
 ==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>
+{{Template:HeatOverlay_formula_nav}}

Temperature formulas (Heat Overlay): Difference between revisions

Latest revision as of 11:53, 13 September 2021

Atmospheric Temperature formula

Wet-bulb Temperature formula

See also

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