relationship between temperature and relative humidity

why as temperature increse, relative humidity will also increase??

The relative humidity of a system is dependent not only on the temperature but also on the absolute pressure of the system of interest. Therefore, a change in relative humidity can be explained by a change in system temperature, a change in the absolute pressure of the system, or change in both of these system properties.


圖片參考：http://upload.wikimedia.org/wikipedia/commons/8/84/Relative_humidity.jpg

is it related to the formula of relative humidity?

Humidity is responsive to change of temperature AND air pressure. But "relative humidity" has no relationship with temperture by definition:



圖片參考：http://upload.wikimedia.org/math/1/d/f/1df6628a7fd427a2cb0fb4484a186d93.png

where:


圖片參考：http://upload.wikimedia.org/math/5/3/a/53a51e378768114b5b2713b4809ff615.png
is the relative humidity of the gas mixture being considered;

圖片參考：http://upload.wikimedia.org/math/4/3/4/43429ff5de667f48efa72b8d43e92725.png
is the partial pressure of water vapor in the gas mixture; and

圖片參考：http://upload.wikimedia.org/math/8/0/4/804278b0d3a8888d718deb0284ffd80e.png
is the saturation vapor pressure of water at the temperature of the gas mixture.
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