Greenhouse effect: Difference between revisions

Latest revision as of 12:52, 9 December 2015

greenhouse effect[edit | edit source]

As used in the field of meteorology, the term “greenhouse effect” refers to the heating exerted by the atmosphere on Earth’s surface because certain atmospheric constituents (clouds, water vapor, carbon dioxide, etc.) absorb and emit infrared radiation.

About half of the sunlight incident on Earth is transmitted through the atmosphere and absorbed at Earth’s surface. The sunlight-warmed surface emits radiation but, because Earth is colder than the sun, this radiation is primarily at infrared wavelengths. Most of this emitted infrared radiation is absorbed by trace gases and clouds in the overlying atmosphere. The atmosphere also emits radiation, primarily at infrared wavelengths, in all directions. Radiation emitted downward from the atmosphere adds to the warming of Earth’s surface by sunlight. This enhanced warming is termed the greenhouse effect.

As a result of the greenhouse effect, Earth’s annual mean surface temperature of 15°C is 33°C higher than an equally reflective planet in Earth’s orbit with no atmosphere.

The term “greenhouse effect“ is something of a misnomer in this context. It is used as an analogy to the trapping of heat by the glass panes of a greenhouse, which let sunlight in. In the atmosphere, however, heat is trapped radiatively, while in an actual greenhouse, heat is mechanically prevented from escaping (via convection) by the glass enclosure.

term edited 9 December 2015

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    <div class="term">
 == greenhouse effect ==
-   </div>
+<div class="definition"><div class="short_definition">As used in the field of [[meteorology]], the term “greenhouse effect” refers to the heating exerted by the [[atmosphere]] on Earth’s surface because certain atmospheric constituents ([[clouds]], [[water vapor]], [[carbon dioxide]], etc.) absorb and emit infrared radiation.
-<div class="definition"><div class="short_definition">The heating effect exerted by the [[atmosphere]] upon the earth because certain  [[trace gases]] in the atmosphere ([[water vapor]], [[carbon dioxide]], etc.) absorb and reemit [[infrared  radiation]].</div><br/> <div class="paragraph">Most of the [[sunlight]] incident on the earth is transmitted through the atmosphere and absorbed  at the earth's surface. The surface tries to maintain [[energy balance]] in part by emitting its own  [[radiation]], which is primarily at the [[infrared]] wavelengths characteristic of the earth's [[temperature]].  Most of the [[heat]] radiated by the surface is absorbed by trace gases in the overlying atmosphere  and reemitted in all directions. The component that is radiated downward warms the earth's surface  more than would occur if only the direct sunlight were absorbed. The magnitude of this enhanced  warming is the greenhouse effect. Earth's annual mean surface temperature of 15&deg;C is 33&deg;C higher  as a result of the greenhouse effect than the [[mean temperature]] resulting from [[radiative equilibrium]]  of a [[blackbody]] at the earth's mean distance from the sun. The term &ldquo;greenhouse effect&rdquo; is  something of a misnomer. It is an analogy to the trapping of heat by the glass panes of a greenhouse,  which let sunlight in. In the atmosphere, however, heat is trapped radiatively, while in an actual  greenhouse, heat is mechanically prevented from escaping (via [[convection]]) by the glass enclosure.</div><br/> </div>
+	About half of the [[sunlight]] incident on Earth is transmitted through the atmosphere and absorbed at Earth’s surface. The sunlight-warmed surface emits [[radiation]] but, because Earth is colder than the sun, this radiation is primarily at [[infrared]] [[wavelengths]]. Most of this emitted infrared radiation is absorbed by trace gases and clouds in the overlying atmosphere. The atmosphere also emits radiation, primarily at infrared wavelengths, in all directions. Radiation emitted downward from the atmosphere adds to the warming of Earth’s surface by sunlight. This enhanced warming is termed the greenhouse effect.
-</div>
+As a result of the greenhouse effect, Earth’s annual mean surface [[temperature]] of 15°C is 33°C higher than an equally reflective planet in Earth’s orbit with no atmosphere.
+The term “greenhouse effect“ is something of a misnomer in this context. It is used as an analogy to the trapping of heat by the glass panes of a greenhouse, which let sunlight in. In the atmosphere, however, [[heat]] is trapped radiatively, while in an actual greenhouse, heat is mechanically prevented from escaping (via [[convection]]) by the glass enclosure.
+</div><br/> </div>
+''term edited 9 December 2015''
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 [[Category:Terms_G]]