Wet Bulb Global Temperature
The first temperature, (Tg), is measured by the black globe thermometer, which usually consists of a 150 mm (6 inch) black globe with a thermometer located at the centre. The black globe temperature represents the integrated effects of radiation and wind.
The second thermometer (not easily viewed on the picture) measures the natural wet-bulb temperature (Tnwb). It consists of a thermometer with its bulb covered with a wettened cotton wick supplied with distilled water from a reservoir. Evaporation from the wettened bulb cools the thermometer. The natural wet-bulb thermometer, like the black globe thermometer is not shielded from wind or radiation. This thermometer represents the integrated effect of humidity, wind and radiation.
The final temperature element is the (shade) air temperature (Ta). It is measured by a thermometer shielded from radiation - generally by being placed in a weather screen. It is the standard temperature normally quoted in weather observations and forecasts.
The three elements Tg, Tnwb, and Ta are combined by into a weighted average to produce the WBGT.
WBGT = 0.7 × Tnwb + 0.2 × Tg + 0.1 × Ta
Ja het kan, maar je moet dus wel 2 thermometers hebben en een speciale opstelling.
Bericht laatst bijgewerkt: 04-06-2007 23:31
