查看“︁逸入 (氣象學)”︁的源代码

[[File:Entrainment_Detrainment_en.svg|缩略图|對流雲周圍的空氣流動示意圖]]
'''逸入'''是指[[大氣]]中的[[湍流|擾流]]捕捉到附近非擾流的過程。通常用在[[對流]]發展時，附近較乾氣塊進入對流氣柱中，與濕空氣混和的過程。

'''逸出'''則是與逸入相反，為對流氣柱中空氣離開氣柱、進入環境的過程。通常發生在對流氣柱的頂端。

== 理論 ==
[[File:Entrainment.png|缩略图|上圖顯示出不同[[積雨雲]]中逸入率 (<math>\lambda</math>)對雲內垂直溫度的影響。逸入率越高，則雲內溫度越傾向環境[[溫度]](T)的分布。]]
逸入是環境中的空氣與氣柱裡或雲裡的空氣混和的作用，部分環境中的空氣性質會進入到雲內。由於逸入作用會改變雲的性質，進而影響到[[降水]]、[[輻射]]...等，因此雲內的逸入係數設定對[[氣候]][[模式]]的模擬影響相當大。<ref>Knight CG, Knight SHE, Massey N, Aina T, Christensen C, et al., (2007). </ref>

逸入作用可分成同質及異質混和過程。同質混和過程是一個假設雲內混和作用的時間尺度小於[[蒸發]]的時間尺度的模式。這意味著當環境裡的未[[飽和]]乾空氣在使雲水蒸發之前，已有足夠的時間逸入到雲內，並與雲內空氣混和。透過同質混和過程的逸入作用，並不影響雲內的雲滴數量，只會使雲滴的部分液態水蒸發。<ref name="jonas-1996">Jonas, P.R., (1996). </ref><ref name="Lu">Lu C., Y. Liu, S. Niu, S. Krueger, and T. Wagner, 2013: [http://onlinelibrary.wiley.com/doi/10.1029/2012JD018464/abstract Exploring parameterization for turbulent entrainment-mixing processes in clouds] {{Wayback|url=http://onlinelibrary.wiley.com/doi/10.1029/2012JD018464/abstract |date=20170712055709 }}.</ref> 與同質混和相對應的是異質混和過程，其雲滴蒸發的時間尺度短於混和的時間尺度，因此雲內的飽和氣塊會在逸入作用的區域被完全蒸發，使總雲滴數量減少。

這兩種模式的差距主要在於雲滴粒徑譜上的表現。在同質混和中，由於大、小雲滴的過飽和水氣壓並不相同，改變了粒徑分布曲線的形狀，因此同質混和後的雲滴粒徑分布將會變窄，而異質混和則不影響雲滴粒徑分布。

== 逸入率 ==
[[積雲]]在大氣中扮演著傳輸能量和水氣的重要角色，也影響著地球的氣候，但是在大尺度的模式當中，積雲無法直接被模擬而需要[[參數化]]。逸入率的決定又牽動著積雲內的性質，因此這個參數對積雲參數化來說相當重要。相關的研究中以[[Henry Stommel]]為積雲內逸入係數研究的先鋒科學家。<ref>Stommel, H. Entrainment of air into a cumulus cloud. </ref>

== 參考資料 ==
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== 更多相關 ==
* Lu C., S. Niu, Y. Liu, A. Vogelmann, 2013: [http://onlinelibrary.wiley.com/doi/10.1002/grl.50445/abstract Empirical relationship between entrainment rate and microphysics in cumulus clouds] {{Wayback|url=http://onlinelibrary.wiley.com/doi/10.1002/grl.50445/abstract |date=20170202052115 }}. Geophys. Res. Lett., 40, 2333-2338.
* Lu C., Y. Liu, and S. Niu, 2013: [https://web.archive.org/web/20140308162421/http://csb.scichina.com:8080/kxtbe/EN/abstract/abstract507511.shtml A method for distinguishing and linking turbulent entrainment mixing and collision-coalescence in stratocumulus clouds]. Chin. Sci. Bull., 58, 545-551.
* Lu C., Y. Liu, S. Niu, A. Vogelmann, 2012: [http://onlinelibrary.wiley.com/doi/10.1029/2012GL053646/abstract Lateral entrainment rate in shallow cumuli: Dependence on dry air sources and probability density functions] {{Wayback|url=http://onlinelibrary.wiley.com/doi/10.1029/2012GL053646/abstract |date=20170109144321 }}. Geophys. Res. Lett., 39, L20812. 
* Lu C., Y. Liu, S. Yum, S. Niu, S. Endo, 2012: [http://onlinelibrary.wiley.com/doi/10.1029/2011GL050546/abstract A new approach for estimating entrainment rate in cumulus clouds] {{Wayback|url=http://onlinelibrary.wiley.com/doi/10.1029/2011GL050546/abstract |date=20150629052058 }}. Geophys. Res. Lett., 39, L04802. 
* Lu C., Y. Liu, and S. Niu, 2014: [http://link.springer.com/article/10.1007%2Fs11434-013-0097-1# Entrainment mixing parameterization in shallow cumuli and effects of secondary mixing events] {{Wayback|url=http://link.springer.com/article/10.1007%2Fs11434-013-0097-1 |date=20200211052719 }}. Chinese Sci. Bull., 59(9), 896-903.
* Lu C., Y. Liu, and S. Niu, 2011: [http://onlinelibrary.wiley.com/doi/10.1029/2011JD015944/abstract Examination of turbulent entrainment-mixing mechanisms using a combined approach] {{Wayback|url=http://onlinelibrary.wiley.com/doi/10.1029/2011JD015944/abstract |date=20150330045614 }}. J. Geophys. Res., 116, D20207. 
* Burnet, F., and J.L. Brenguier, 2007: Observational Study of the Entrainment-Mixing Process in Warm Convective Clouds. J. Atmos. Sci., 64, 1995–2011.
* Chosson, F., J.L. Brenguier, and L. Schüller, 2007: Entrainment-Mixing and Radiative Transfer Simulation in Boundary Layer Clouds. J. Atmos. Sci., 64, 2670–2682.
* Hill, A.A., G. Feingold, and H. Jiang, 2009: The Influence of Entrainment and Mixing Assumption on Aerosol–Cloud Interactions in Marine Stratocumulus. J. Atmos. Sci., 66, 1450–1464.
* Hicks, E., C. Pontikis, and A. Rigaud, 1990: Entrainment and Mixing Processes as Related to Droplet Growth in Warm Midlatitude and Tropical Clouds. J. Atmos. Sci., 47, 1589–1618.
* Pontikis, C.A., and E.M. Hicks, 1993: Droplet Activation as Related to Entrainment and Mixing in Warm Tropical Maritime Clouds. J. Atmos. Sci., 50, 1888–1896.
* Baker, B.A., 1992: Turbulent Entrainment and Mixing in Clouds: A New Observational Approach. J. Atmos. Sci., 49, 387–404.
* Paluch, I.R., 1979: The Entrainment Mechanism in Colorado Cumuli. J. Atmos. Sci., 36, 2467–2478.
* Baker, M., and J. Latham, 1979: The Evolution of Droplet Spectra and the Rate of Production of Embryonic Raindrops in Small Cumulus Clouds. J. Atmos. Sci., 36, 1612–1615.
* Baker, M.B., R.G. Corbin, and J. Latham, 1980, The influence of entrainment on the evolution of cloud droplet spectra: I. A model of inhomogeneous mixing. Quarterly Journal of the Royal Meteorological Society, 106, 581-598.

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[[Category:雲物理學]]