THSW index（单位是C）是温湿度阳光风指数。
THSW指数是温度，湿度，辐射，风四个参数综合起来的一个参数，主要表示为温度数值，体现人体的舒适程度。
THSW INDEX
Parameters Used:Temperature, Humidity, Solar Radiation, Wind Speed, Latitude & Longitude, Time and Date
What is it:Like Heat Index, the THSW Index uses humidity and temperature to calculate an apparent temperature. In addition, THSW incorporates the heating effects of solar radiation and the cooling effects of wind (like wind chill) on our perception of temperature.
Formula:The formula was developed by Steadman (1979). The following describes the series of
formulas used to determine the THSW or Temperature-Humidity-Sun-Wind Index. Thus, this index indicates the level of thermal comfort including the effects of all these values.
This Index is calculated by adding a series of successive terms. Each term represents one of the three parameters: (Humidity, Sun & Wind). The humidity term serves as the base from which increments for sun and wind effects are added.
The Vantage Pro calculation is an improvement over the THSW Index in the Health EnviroMonitor because the Health system:
o only calculates THSW Index when air temperature is at or above 68°F.
o assumes the sky is clear.
o assumes the elevation is sea level.
