PET formulas (Heat Overlay): Difference between revisions
Jump to navigation
Jump to search
| Line 9: | Line 9: | ||
where, | where, | ||
* | * <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>u_{t}</math> is the calculated [[Wind_speed_formula_(Heat_Overlay)|wind speed]] at 1.2m 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>\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>S_{vf}</math> is the calculated [[Sky_view_factor_formula_(Heat_Overlay)|sky view factor]]. | ||
==PET Shade and Night formula== | ==PET Shade and Night formula== | ||
Revision as of 11:42, 20 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:
Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle PET_{sun} = -13.26 + 1.25 \cdot T_{a,t}+ 0.011 \cdot Q_{gl,t} - 3.37 \cdot ln(u_t) + 0.078 \cdot T_{w,t} + 0.0055 \cdot Q_{gl,t} \cdot ln(u)+ 5.56 \cdot sin(\phi_{t}) - 0.0103 \cdot Q_{gl,t} \cdot ln(u_t) \cdot sin(\phi_{t}) + 0.546 \cdot B_{b,t} + 1.94 \cdot S_{vf} }
where,
- Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle T_{a,t}} is the calculated atmospheric temperature at time t;
- Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle Q_{gl,t}} is the hourly radiation at time t;
- Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle u_{t}} is the calculated wind speed at 1.2m above ground time t;
- Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle T_{w,t}} is the calculated wet-bulb temperature at time t;
- Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \phi_{t}} is the sun altitude at time t;
- Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle B_{b,t}} is the bowen ratio at time t;
- Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle S_{vf}} is the calculated sky view factor.
PET Shade and Night formula
The PET shade and night formula is as followed:
PETshade,night,t = -12.14 + 1.25 · Ta,t - 1.47 · ln(ut) + 0.060 · Tw,t + 0.015 · SvfQd,t + 0.0060 · (1-Svf) · σ · (Ta,t+273.15)4
where,
- Ta,t is the calculated atmospheric temperature 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;
- Svf is the calculated sky view factor;
- Qd,t is the calculated diffusive radiation at time t;
- σ is the Stefan Boltzmann constant, which is 5.670374419...×10-8 W⋅m-2⋅K-4.
