Editing Troposphere (section)

====Humidity====
If the air contains [[water vapor]], then cooling of the air can cause the water to condense, and the air no longer functions as an ideal gas. If the air is at the [[saturation vapor pressure]], then the rate at which temperature decreases with altitude is called the [[Lapse rate#Moist adiabatic lapse rate|saturated adiabatic lapse rate]]. The actual rate at which the temperature decreases with altitude is the [[Lapse rate#Environmental lapse rate|environmental lapse rate]]. In the troposphere, the average environmental lapse rate is a decrease of about 6.5&nbsp;°C for every 1.0&nbsp;km (1,000m) of increased altitude.<ref name="DLA"/>
For dry air, an approximately [[ideal gas]], the adiabatic equation is: <math> p(z) \Bigl[T(z)\Bigr]^{-\frac{\gamma}{\,\gamma\,-\,1\,}} = \text{constant}</math> wherein <math>\gamma</math> is the [[heat capacity ratio]] (<math>\gamma \approx \,</math>{{frac|7|5}}) for air. The combination of the equation for the air pressure yields the [[Lapse rate#Dry adiabatic lapse rate|dry adiabatic lapse rate]]:<math>\frac{\,dT\,}{dz} = - \frac{\; m g \;}{R} \frac{\;\gamma\,-\,1\;}{\gamma} = -9.8^\circ\mathrm{C/km}</math>.<ref>{{cite book |vauthors=Kittel C, Kroemer H |title=Thermal Physics |publisher=Freeman |year=1980 |at=chapter&nbsp;6, problem&nbsp;11}}</ref><ref name="LL1">{{cite book |vauthors=Landau LD, Lifshitz EM |title=Statistical Physics |series=Part&nbsp;1 |publisher=Pergamon |year=1980}}</ref>