Temperature formulas (Heat Overlay)
Revision as of 09:35, 12 September 2019 by Frank@tygron.nl (talk | contribs) (→Atmospheric Temperature formula)
Two temperature formulas are used in the calculation of the PET value:
- The atmospheric temperature Ta
- The wet-bulb temperatur Tw
Atmospheric Temperature formula
Ta,t = Tstation,t + UHImax,t · fsun,t
where
- Ta,t is the calculated atmospheric temperature at time t;
- Tstation,t is the temperature measured at a weather station at time t;
- UHImax,t is the calculated Urban Heat Island effect at time t;
- fsun,t is the sun daily motion factor at time t;
Wet-bulb Temperature formula
Tw,t = Ta,t · atan( 0.151977 · (ϕ + 8.313659)0.5) + atan (Ta + ϕ) - atan(ϕ - 1.676331) + 0.00391838 · ϕ3/2 atan(0.023101 · ϕ) - 4.686935
where:
- Tw,t is the calculated wet-bulb temperature;
- Ta,t is the calculated atmospheric temperature;
- ϕ is the sun altitude angle;