Vaisala AWS330 - Manual (Page 276)

User's Guide ______________________________________________________________________
274 _________________________________________________________________ M211296EN-B
Heat Index
The heat index measures how hot it feels when the effect of humidity is
added to high temperature. This calculation uses two source values,
temperature and humidity, and produces one result value, the heat index.
The calculation formula is as follows:
HI = 16.923 +
0.185212 * TA +
5.379410 * RH –
0.100254 * TA*RH +
9.41695*10
-3 * TA 2 +
7.28898*10 -3 * RH 2 +
3.45372*10 -4 * TA 2 *RH –
8.14971*10 -4 * TA*RH 2 +
1.02102*10 -5 * TA 2 *RH 2 –
3.86460*10 -5 * TA 3 +
2.91583*10 -5 * RH 3 +
1.42721*10 -6 * TA 3 *RH +
1.97483*10 -7 * TA*RH 3 –
2.18429*10 -8 * TA 3 *RH 2 +
8.43296*10 -10 * TA 2 *RH 3 –
4.81975*10 -11 * TA 3 *RH 3
where
RH
= Relative humidity [%]
TA = Air temperature [F ° ]
HI = Heat index [F ° ]
Table 113 Inputs for Heat Index Calculation
Input Variable
Air temperature (TA)
TAAVG1M; see Table 4 on page 22 (1
Relative humidity (RH) RHAVG1M; see Table 4 on page 22
1) Converted internally to degrees Fahrenheit.