Editing Dew point (section)

==Altitude and clouds==
A rising air mass in the atmosphere will [[adiabatic cooling|cool]] as the pressure reduces: its temperature will move closer to the dew point temperature. The relative humidity of this air increases as the pressure drops with the same amount of water vapor. This combination causes the dew point temperature to fall 4.5 degrees F per 1000 ft or 0.2C per 100m. At the elevation where the dew point is reached condensation begins, creating clouds, or fog as it is called a low altitudes. [[Cumulus cloud]]s tend to have flat bottoms marking the altitude where the temperature crosses the dew point. The condensation of water vapor into water droplets releases 600 calories of energy per gram of water, heating the surrounding air.<ref name=Strahler-1963>Strahler, A. N. (1963). [https://archive.org/details/earthsciences0002arth/page/292/mode/2up?q=%22dew+point%22 The Earth Sciences]. Japan: Harper & Row.</ref>{{rp|292}}