2007-01-09 10:15:55 · 6 answers · asked by Linda 1 in Science & Mathematics ➔ Weather
Dew point temperature is defined as the temperature to which the air would have to cool (at constant pressure and constant water vapor content) in order to reach saturation. A state of saturation exists when the air is holding the maximum amount of water vapor possible at the existing temperature and pressure.
When the dew point temperature and air temperature are equal, the air is said to be saturated. Dew point temperature is NEVER GREATER than the air temperature. Therefore, if the air cools, moisture must be removed from the air and this is accomplished through condensation. This process results in the formation of tiny water droplets that can lead to the development of fog, frost, clouds, or even precipitation.
2007-01-09 10:48:19 · answer #1 · answered by cherokeeflyer 6 · 3⤊ 0⤋
Air does not "hold"water vapour any more than it holds oxygen, nitrogen or carbon dioxide. This is a myth still taught, unfortunately, in some schools and even universities.
Water vapour in the air is constantly changing its state by condensing into water droplets and evaporating from water droplets to water vapour. If the rate of evaporation exceeds the rate of condensation, the air is clear. The amount of water vapour in the air depends on where the air comes from. Air off the sea will have more water vapour than air off the land.
With any air mass, there is a temperature to which the air can be cooled so that the rate of evaporation exactly matches the rate of condensation. At this point, the relative humidity is 100% and the air is said to be saturated. Another term is that the air is at its saturation vapour pressure. This temperature is the Dew Point. If the temperature falls below the Dew Point, condensation exceeds evaporation and dew will form on the ground or fog or cloud will develop.
2007-01-09 14:10:20 · answer #2 · answered by tentofield 7 · 1⤊ 0⤋
Dew point is the temperature at which the moisture in the air begins to condense.It will be less if the moisture in the air is less and more if the moisure is more.Both the dewpoint and dry bulb temperature(air temperature) will be same if the air is saturated with water. At that time humidity will be 100 percent.This may happen when there is heavy rain.
2007-01-11 00:57:00 · answer #3 · answered by Arasan 7 · 0⤊ 0⤋
Dew Point is measured in degrees. (F or C) and it is the temperature where water vapour condenses out of air. Where the temperature is close to the dew point, we see fog. Where the temperature is close to the dew point at ground level, we see dew on the grass. To calculate the dew point you need to know the humidity (measured with an hygrometer) as it relates to the temperature (as measured with a thermometer),
2016-05-23 00:08:37 · answer #4 · answered by Anonymous · 0⤊ 0⤋
tentofield is right about how the atmosphere does not "hold" moisture. I recently learned this in a class of mine, it's a shame it's still being so widely taught.
And dewpoint is the temp to which the air must be cooled in order to reach saturation, as has already been pointed out.
2007-01-10 12:51:04 · answer #5 · answered by Anonymous · 0⤊ 0⤋
If I remember correctly, that is the point where the atmosphere is saturated and cannot absorb any more moisture.
2007-01-09 10:24:01 · answer #6 · answered by Anonymous · 0⤊ 0⤋