Editing Altitude (section)

===Temperature profile===
{{main|Lapse rate}}
{{Further|Atmospheric temperature}}

The temperature profile of the atmosphere is a result of an interaction between [[radiation]] and [[convection]]. Sunlight in the [[visible spectrum]] hits the ground and heats it. The ground then heats the air at the surface. If [[radiation]] were the only way to transfer heat from the ground to space, the [[greenhouse effect]] of gases in the atmosphere would keep the ground at roughly {{convert|333|K|C F}}, and the temperature would decay exponentially with height.<ref name=goodywilson>{{cite book|first1=Richard M.|last1=Goody|first2=James C.G.|last2=Walker|title=Atmospheres|chapter=Atmospheric Temperatures|chapter-url=http://lasp.colorado.edu/~bagenal/3720/GoodyWalker/AtmosCh3sm.pdf|publisher=Prentice-Hall|year=1972|access-date=2 May 2016|archive-date=29 July 2016|archive-url=https://web.archive.org/web/20160729075851/http://lasp.colorado.edu/~bagenal/3720/GoodyWalker/AtmosCh3sm.pdf}}</ref>

However, when air is hot, it tends to expand, which lowers its density. Thus, hot air tends to rise and transfer heat upward. This is the process of [[convection]]. Convection comes to equilibrium when a parcel of air at a given altitude has the same density as its surroundings. Air is a poor conductor of heat, so a parcel of air will rise and fall without exchanging heat. This is known as an [[adiabatic process]], which has a characteristic pressure-temperature curve. As the pressure gets lower, the temperature decreases. The rate of decrease of temperature with elevation is known as the [[adiabatic lapse rate]], which is approximately 9.8&nbsp;°C per kilometer (or {{convert|5.4|F-change|C-change|abbr=on|disp=sqbr}} per 1000&nbsp;feet) of altitude.<ref name=goodywilson/>

The presence of water in the atmosphere complicates the process of convection. Water vapor contains latent [[heat of vaporization]]. As air rises and cools, it eventually becomes [[Dew point|saturated]] and cannot hold its quantity of water vapor. The water vapor condenses (forming [[cloud]]s), and releases heat, which changes the lapse rate from the [[dry adiabatic lapse rate]] to the [[moist adiabatic lapse rate]] (5.5&nbsp;°C per kilometer or {{convert|3|F-change|C-change|abbr=on|disp=sqbr}} per 1000&nbsp;feet).<ref>{{cite web|url=http://meteorologytraining.tpub.com/14312/css/14312_47.htm |title=Dry Adiabatic Lapse Rate |publisher=tpub.com |access-date=2 May 2016  |archive-url=https://web.archive.org/web/20160603041448/http://meteorologytraining.tpub.com/14312/css/14312_47.htm |archive-date=3 June 2016 }}</ref>
As an average, the International Civil Aviation Organization (ICAO) defines an [[international standard atmosphere]] (ISA) with a temperature [[lapse rate]] of 6.49&nbsp;°C per kilometer (3.56&nbsp;°F per 1,000&nbsp;feet).<ref name="ICAO 1993">{{cite book|publisher=[[International Civil Aviation Organization]]|title=Manual of the ICAO Standard Atmosphere (extended to 80 kilometres (262 500 feet))|id=Doc 7488-CD|edition=Third|year=1993|isbn=978-92-9194-004-2}}</ref> The actual lapse rate can vary by altitude and by location.

Finally, only the [[troposphere]] (up to approximately {{convert|11|km|ft}} of altitude) in the Earth's atmosphere undergoes notable convection; in the [[stratosphere]], there is little vertical convection.<ref>{{cite web|url=http://scied.ucar.edu/shortcontent/stratosphere-overview|title=The stratosphere: overview|publisher=UCAR|access-date=2 May 2016}}</ref>