PET formulas (Heat Overlay): Difference between revisions

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* <math>T_{a,t}</math> is the calculated [[Temperature_formulas_(Heat_Overlay)#Atmospheric_Temperature_formula |atmospheric temperature]] at time t;
* <math>T_{a,t}</math> is the calculated [[Temperature_formulas_(Heat_Overlay)#Atmospheric_Temperature_formula |atmospheric temperature]] at time t;
* <math>Q_{gl,t}</math> is the [[Hourly_radiation_(Heat_Overlay)|hourly radiation]] at time t;
* <math>Q_{gl,t}</math> is the [[Hourly_radiation_(Heat_Overlay)|hourly radiation]] at time t;
* <math>u_{t}</math> is the calculated [[Wind_speed_formula_(Heat_Overlay)|wind speed]] at 1.2 meters above ground time t;
* <math>u_{t}</math> is the calculated [[Wind_calculation_model_(Heat_Overlay)|wind speed]] at 1.2 meters above ground time t;
* <math>T_{w,t}</math> is the calculated [[Temperature_formulas_(Heat_Overlay)#Wet-bulb_Temperature_formula | wet-bulb temperature]] at time t;
* <math>T_{w,t}</math> is the calculated [[Temperature_formulas_(Heat_Overlay)#Wet-bulb_Temperature_formula | wet-bulb temperature]] at time t;
* <math>\phi_{t}</math> is the [[Sun_altitude_(Heat_Overlay)|sun altitude]] at time t;
* <math>\phi_{t}</math> is the [[Sun_altitude_(Heat_Overlay)|sun altitude]] at time t;
* <math>B_{b,t}</math> is the [[Bowen_ratio_(Heat_Overlay)|bowen ratio]] at time t;
* <math>B_{b,t}</math> is the [[Bowen_ratio_(Heat_Overlay)|bowen ratio]] at time t;
* <math>S_{vf}</math> is the calculated [[Sky_view_factor_calculation_model_(Heat_Overlay)|sky view factor]].
* <math>S_{vf}</math> is the calculated [[Sky_view_factor_calculation_model_(Heat_Overlay)|sky view factor]].
* Constant values are sourced from the {{Heat DPRA Report}};


==PET Shade and Night formula==
==PET Shade and Night formula==
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where,
where,
* <math>T_{a,t}</math> is the calculated [[Temperature_formulas_(Heat_Overlay)#Atmospheric_Temperature_formula |atmospheric temperature]] at time t;
* <math>T_{a,t}</math> is the calculated [[Temperature_formulas_(Heat_Overlay)#Atmospheric_Temperature_formula |atmospheric temperature]] at time t;
* <math>u_{t}</math> is the calculated [[Wind_speed_formula_(Heat_Overlay)|wind speed]] at 1.2 meters above ground time t;
* <math>u_{t}</math> is the calculated [[Wind_calculation_model_(Heat_Overlay)|wind speed]] at 1.2 meters above ground time t;
* <math>T_{w,t}</math> is the calculated [[Temperature_formulas_(Heat_Overlay)#Wet-bulb_Temperature_formula | wet-bulb temperature]] at time t;
* <math>T_{w,t}</math> is the calculated [[Temperature_formulas_(Heat_Overlay)#Wet-bulb_Temperature_formula | wet-bulb temperature]] at time t;
* <math>S_{v,f}</math> is the calculated [[Sky_view_factor_calculation_model_(Heat_Overlay)|sky view factor]];
* <math>S_{v,f}</math> is the calculated [[Sky_view_factor_calculation_model_(Heat_Overlay)|sky view factor]];
* <math>Q_{d,t}</math> is the calculated [[Diffuse_radiation_formula_(Heat_Overlay)|diffusive radiation]] at time t;
* <math>Q_{d,t}</math> is the calculated [[Diffuse_radiation_formula_(Heat_Overlay)|diffusive radiation]] at time t;
* <math>\sigma</math> is the Stefan Boltzmann constant, which is <math>5.670374419...\times 10^{-8} W \cdot m^{-2} \cdot K^{-4}</math>.
* <math>\sigma</math> is the Stefan Boltzmann constant, which is <math>5.670374419...\times 10^{-8} W \cdot m^{-2} \cdot K^{-4}</math>.
* Constant values are sourced from the {{Heat DPRA Report}};


{{Template:HeatOverlay_formula_nav}}
{{Template:HeatOverlay_formula_nav}}

Latest revision as of 11:52, 13 September 2021

The physiological equivalent temperature PET is calculated for two possible options based on the situation:

  • A cell is in the shade or it is night at time t: PETshade, night;
  • A cell is in the sun during the day: PETsun;

PET Sun formula

The PET sun formula is as followed:

where,

PET Shade and Night formula

The PET shade and night formula is as followed:

where,

  • is the calculated atmospheric temperature at time t;
  • is the calculated wind speed at 1.2 meters above ground time t;
  • is the calculated wet-bulb temperature at time t;
  • is the calculated sky view factor;
  • is the calculated diffusive radiation at time t;
  • is the Stefan Boltzmann constant, which is .
  • Constant values are sourced from the DPRA Heat stress report;