What is the Relationship between relative humidty and air pressure and temperature and relative humidty?

What is the Relationship between relative humidty and air pressure and temperature and relative humidty?

Relevance

At the Standard Atmosphere (average on earth) of 1013.25 hectoPascal, and temperature of 15 degrees Celsius, a cubic meter of air can't contain more than 13 grams of water. The air is then at dew point and the relative humidity is 100 percent.

When the temperature sinks, the air can only contain less humidity and that's why clouds form when moist air rises and cools down with altitude.

In other words, the higher the temperature and the higher the pressure, the more humidity can be sustained in the air.

A simple rule of thumb to used by airmen to find the relative humidity, knowing the outside temperature and the dew point temperature - both given by the aviation METAR reports - is to do: 100 - (5 x spread).

The spread is the difference between outside and dew point temperatures. As an example, if the temperature is 15 C and dew point is 11 C, the spread is 4 C and the relative humidity is 100 - (5 x 4) = 80 percent. Relative humidity is important for light aircraft piston engines because it warns when carburettor icing may occur.

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Lv 4
4 years ago

Your instructor is right. the reason lies in atmospheric composition. the ambience is seventy 8% Nitrogen, 21% Oxygen, and a million% hint different gasses (alongside with water vapour) Nitrogen and Oxygen are the two diatomic, that's they exist bonded in pairs so N-N and O-O. So the burden could be 28 grams/mol and 32 grams/mol respectively. warmth up a parcel of completely dry air, the intermolecular distances could enhance as they are greater excited. Water (H20) could replace out a variety of debris if we necessary to enhance the humidity of that parcel of air. H20 sits at 18.02 grams/mol So the parcel of air with one molecule of the two N2 or O2 substituted by using H20 has its humidity greater advantageous and its weight decreased. Cheers! Chris Pilot and HS Sci instructor