大気熱力学のソースを表示

{{翻訳中途|1=[[:en:Atmospheric thermodynamics]] 09:32, 29 February 2012|date=2012年7月4日 (水) 18:47 (UTC)}}
'''大気熱力学'''（たいきねつりきがく、[[英語]]：atmospheric thermodynamics）とは、[[気象学]]（[[大気科学]]）の中でも、[[熱]]の働きが関与する[[気象]]を扱う[[学問]]である。'''気象熱力学'''ともいう。

古典的な[[熱力学]]の法則を用いて、湿潤大気、さまざまな[[雲]]、[[対流]]現象、[[大気境界層]]の諸現象、[[大気安定度]]などを研究する。また、[[熱力学ダイアグラム]]は[[荒天]]の予測に用いられる。大気熱力学の成果は、雲の発達モデルや対流モデルとして[[数値予報]]モデルに組み込まれて[[天気予報]]や[[気候モデル|気候の予測]]に応用されている。

[[File:Skew-T.gif|thumb|right|250px|[[Skew-T log-P図]]。[[19世紀]]に開発された熱力学ダイアグラムは現在も大気のエネルギー計算に使用されている。]]
大気熱力学の理論の中では、熱を輸送する重要な因子である[[水]]とその変化が大きなウェイトを占める。[[対流圏]]においては大抵、微量成分を無視し、大気を理想気体と[[水蒸気]]により構成されるものとして取り扱った上で、[[エネルギー保存則]]、[[理想気体の状態方程式]]、[[比熱容量]]、[[エントロピー]]が保存される系である[[断熱過程]]等を組み入れて大気の振る舞いを論じる。

特化した分野では、水の[[相転移]]、[[大気エアロゾル粒子]]と呼ばれるような均質・不均質の微粒子、[[気液平衡]]と雲の凝結、[[氷晶]]・[[雲粒]]の生成に対する微粒子の関与を研究するものなどがある。また湿潤大気や雲の発生・消滅を論じるときには[[相当温位]]、[[湿球温度]]、[[仮温度]]などを用いて大気の持つエネルギーを表現する。

大気熱力学は大気の断熱的・非断熱的な作用を表現するので、[[プリミティブ方程式]]を通して、大気モデルの各格子点における大気の運動を記述するために必要である。
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== 歴史 == == History ==
In the early 19th century thermodynamicists such as [[Nicolas Léonard Sadi Carnot|Sadi Carnot]], [[Rudolf Clausius]], and [[Emile Clapeyron]] developed mathematical models on the dynamics of bodies fluids and vapors related to the combustion and pressure cycles of atmospheric steam engines; one example is the [[Clausius-Clapeyron equation]].  In 1873, thermodynamicist [[Willard Gibbs]] published "Graphical Methods in the Thermodynamics of Fluids."  

These sorts of foundations naturally began to be applied towards the development of theoretical models of atmospheric thermodynamics which drew the attention of the best minds.  Papers on atmospheric thermodynamics appeared in the 1860s that treated such topics as dry and moist [[adiabatic process]]es. In 1884 [[Heinrich Rudolf Hertz|Heinrich Hertz]] devised first atmospheric thermodynamic diagram ([[emagram]]).<ref>Hertz, H., 1884, Graphische Methode zur Bestimmung der adiabatischen Zustandsanderungen feuchter Luft. Meteor Ztschr, vol. 1, pp. 421-431. English translation by Abbe, C. - The mechanics of the earth's atmsphere. Smithsonian Miscellaneous Collections, 843, 1893, 198-211</ref>  Pseudo-adiabatic process was coined by [[Wilhelm von Bezold|von Bezold]] describing air as it is lifted, expands, cools, and eventually precipitates its water vapor;  in 1888 he published voluminous work entitled "On the thermodynamics of the atmosphere".<ref>Zur Thermodynamik der Atmosphäre. Pts. I, II. Sitz. K. Preuss. Akad. Wissensch. Berlin, pp. 485-522, 1189-1206; Gesammelte Abhandlugen, pp. 91-144. English translation Abbe, C. The mechanics of the earth's atmosphere. Smithsonian Miscellaneous Collections, no 843, 1893, 212-242.</ref>  
 
In 1911 von [[Alfred Wegener]] published a book "Thermodynamik der Atmosphäre", Leipzig, J. A. Barth.
From here the development of atmospheric thermodynamics as a branch of science began to take root. The term "atmospheric thermodynamics", itself, can be traced to [[Frank W. Very]]s 1919 publication:  “The radiant properties of the earth from the standpoint of atmospheric thermodynamics” (Occasional scientific papers of the Westwood Astrophysical Observatory). By the late 1970s various textbooks on the subject began to appear.  Today, atmospheric thermodynamics is an integral part of weather forecasting.
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=== 年表 === === Chronology ===
*'''1751''' Charles Le Roy recognized dew point temperature as point of saturation of air
*'''1782''' [[Jacques Charles]] made hydrogen balloon flight measuring temperature and pressure in Paris
*'''1784''' Concept of variation of temperature with height was suggested
*'''1801-1803''' [[John Dalton]] developed his laws of pressures of vapours
*'''1804''' [[Joseph Louis Gay-Lussac]] made balloon ascent to study weather
*'''1805''' Pierre Simon Laplace developed his law of pressure variation with height
*'''1841''' James Pollard Espy publishes paper on  convection theory of cyclone energy
*'''1889''' Herman von Helmholtz and John William von Bezold used the concept of potential temperature, von Bezold used adiabatic lapse rate and pseudoadiabat
*'''1893''' Richard Asman constructs first aerological sonde (pressure-temperature-humidity)
*'''1894''' John Wilhelm von Bezold used concept of equivalent temperature
*'''1926''' Sir Napier Shaw introduced tephigram
*'''1933''' Tor Bergeron published paper on "Physics of Clouds and Precipitation" describing precipitation from supercooled (due to condensational growth of ice crystals in presence of water drops)
*'''1946''' Vincent J. Schaeffer and Irving Langmuir performed the first cloud-seeding experiment
*'''1986''' K. Emanuel conceptualizes tropical cyclone as Carnot heat engine
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== 近年盛んな研究テーマ == == Applications ==
=== 熱帯低気圧におけるカルノーサイクル === === Tropical cyclone Carnot cycle===
[[File:Anvil convection.jpg|300px|thumb|Air is being moistened as it travels toward convective system. Ascending motion in a deep convective core produces air expansion, cooling, and condensation. Upper level outflow visible as an anvil cloud is eventually descending conserving mass (rysunek - Robert Simmon).]] 
The thermodynamic structure of the hurricane can be modelled as a heat engine <ref>Emanuel, K. A. Annual Review of Fluid Mechanics, 23, 179-196 (1991)</ref> running between sea temperature of about 300K and tropopause which has temperature of about 200K. Parcels of air traveling close to the surface take up moisture and warm, ascending air expands and cools releasing moisture (rain) during the condensation. The release of latent heat energy during the condensation provides mechanical energy for the hurricane. Both a decreasing temperature in the upper troposphere or an increasing temperature of the atmosphere close to the surface will increase the maximum winds observed in hurricanes. When applied to hurricane dynamics it defines a Carnot heat engine cycle and predicts maximum hurricane intensity.
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=== 水蒸気と気候変動 === === Water vapor and global climate change ===
{{Main|Clausius-Clapeyron relation|August-Roche-Magnus approximation}}
The [[Clausius-Clapeyron relation]] shows how the water-holding capacity of the atmosphere increases by about 8% per Celsius increase in [[temperature]]. (It does not directly depend on other parameters like the [[pressure]] or [[density]].) This water-holding capacity, or "[[equilibrium vapor pressure]]," can be approximated using the [[August-Roche-Magnus formula]]
: <math> e_s(T)= 6.1094 \exp \left( \frac{17.625T}{T+243.04} \right)</math>
(where <math>e_s(T)</math> is the equilibrium or [[saturation vapor pressure]] in [[hPa]], and <math>T</math> is temperature in degrees Celsius).  This shows that when atmospheric temperature increases (e.g., due to [[greenhouse gases]]) the [[absolute humidity]] should also increase [[exponential function|exponentially]] (assuming a constant [[relative humidity]]). However, this purely thermodynamic argument is subject of considerable debate because [[convection|convective processes]] might cause extensive drying due to increased areas of [[subsidence (atmosphere)|subsidence]], [[efficiency of precipitation]] could be influenced by the intensity of convection, and because [[cloud formation]] is related to relative humidity.{{Citation needed|date=September 2008}}
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== 参考文献 ==
{{参照方法|section=1|date=2012年7月4日 (水) 18:47 (UTC)}}
* {{cite book | author=Bohren, C.F., and B. Albrecht | title=Atmospheric Thermodynamics | publisher=Oxford University Press | year=1998 | isbn=0-19-509904-4}}
* Curry, J.A. and P.J. Webster, 1999, Thermodynamics of Atmospheres and Oceans. Academic Press, London, 467 pp (textbook for graduates)
* Dufour, L. et, Van Mieghem, J. - Thermodynamique de l'Atmosphère, Institut Royal Meteorologique de Belgique, 1975. 278 pp (theoretical approach). First edition of this book - 1947.
* Emanuel, K.A.(1994): Atmospheric Convection, ''Oxford University Press''. ISBN 0-19-506630-8 (thermodynamics of tropical cyclones).
* Iribarne, J.V. and Godson, W.L., Atmospheric thermodynamics, Dordrecht, Boston, Reidel (basic textbook).
* Petty, G.W., [http://www.sundogpublishing.com/AtmosThermo/Announcement.html A First Course in Atmospheric Thermodynamics], Sundog Publishing, Madison, WI,  ISBN 978-0-9729033-2-5 (undergraduate textbook).
* {{cite book | author=Tsonis, Anastoasios, A.; | title=An Introduction to Atmospheric Thermodynamics | publisher=Cambridge University Press | year=2002 | isbn=0-521-79676-8}}
* von Alfred Wegener, Thermodynamik der Atmosphare, Leipzig, J. A. Barth, 1911, 331pp.
* Wilford Zdunkowski, Thermodynamics of the atmosphere: a course in theoretical meteorology, Cambridge, Cambridge University Press, 2004.
* Lorenz, E. N., 1955, Available potential energy and the maintenance of the general circulation, Tellus, 7, 157-167.
* Emanuel, K, 1986, Part I. An air-sea interaction theory for tropical cyclones,  J. Atmos. Sci. 43, 585, (energy cycle of the mature hurricane has been idealized here as Carnot engine that converts heat energy extracted from the ocean to  mechanical energy).

== 関連項目 ==
* [[気温]]
* [[熱化学]]
* [[雲物理学]]
* [[平衡熱力学]]
* [[非平衡熱力学]]
* [[流体力学]]
* [[熱力学]]
* [[大気力学]]
* [[アルフレート・ヴェーゲナー]]

== 外部リンク ==
* [[:en:Recreational Aviation Australia|Recreational Aviation Australia]], "Atmospheric Thermodynamics" [http://www.auf.asn.au/meteorology/section1a.html part1], [http://www.auf.asn.au/meteorology/section1b.html part2] {{En icon}} - オーストラリアの超軽量飛行機NPOのサイトにおける大気熱力学の概説。

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[[Category:大気熱力学|*]]
[[Category:アルフレート・ヴェーゲナー]]