PET formulas (Heat Overlay): Difference between revisions
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The physiological equivalent temperature PET is calculated for two possible options based on the situation: | 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: PET<sub>shade, night</sub>; | * A cell is in the shade or it is night at time t: PET<sub>shade, night</sub>; | ||
* A cell is in the sun during the day: [[PET Sun formula|PET<sub>sun</sub>]]; | * A cell is in the sun during the day: [[#PET Sun formula|PET<sub>sun</sub>]]; | ||
==PET Sun formula== | ==PET Sun formula== | ||
Revision as of 11:50, 12 September 2019
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:
PETsun = -13.26 + 1.25 · Ta,t + 0.011 · Qgl,t - 3.37 · ln(ut) + 0.078 · Tw,t + 0.0055 · Qgl,t · ln(u) + 5.56 · sin(ϕt) - 0.0103 · Qgl,t · ln(u) · sin(ϕt) + 0.546 · Bb,t + 1.94 · Svf
where,
- Ta,t is the calculated atmospheric temperature at time t;
- Qgl,t is the hourly radiation at time t;
- ut is the calculated wind speed at 1.2m above ground time t;
- Tw,t is the calculated wet-bulb temperature at time t;
- Qgl,t is the hourly radiation at time t;
- ϕt is the sun altitude at time t;
- Bb,t is the bowen ratio at time t;
- Svf is the calculated sky view factor;
