Title: Entrainment, Mixing, and Their Microphysical Influences
Abstract: Chapter 4 Entrainment, Mixing, and Their Microphysical Influences Chunsong Lu, Chunsong Lu Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters / Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, ChinaSearch for more papers by this authorYangang Liu, Yangang Liu Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, USASearch for more papers by this authorXiaoqi Xu, Xiaoqi Xu Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters / Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, ChinaSearch for more papers by this authorSinan Gao, Sinan Gao Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters / Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, ChinaSearch for more papers by this authorCheng Sun, Cheng Sun Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters / Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, ChinaSearch for more papers by this author Chunsong Lu, Chunsong Lu Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters / Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, ChinaSearch for more papers by this authorYangang Liu, Yangang Liu Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, USASearch for more papers by this authorXiaoqi Xu, Xiaoqi Xu Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters / Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, ChinaSearch for more papers by this authorSinan Gao, Sinan Gao Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters / Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, ChinaSearch for more papers by this authorCheng Sun, Cheng Sun Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters / Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, ChinaSearch for more papers by this author Book Editor(s):Yangang Liu, Yangang LiuSearch for more papers by this authorPavlos Kollias, Pavlos KolliasSearch for more papers by this author First published: 30 November 2023 https://doi.org/10.1002/9781119529019.ch4Book Series:Geophysical Monograph Series AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onEmailFacebookTwitterLinkedInRedditWechat Summary Entrainment, subsequent mixing processes, and their microphysical influences in cumulus and stratocumulus clouds are essential to cloud physics and further affect aerosol-cloud interactions, cloud-climate feedbacks, etc. Theoretical understanding of these processes is still not clear and their parameterizations in atmospheric models are in their infancy. This chapter focuses on two aspects: entrainment-mixing mechanisms (cloud microphysics) and entrainment rate (dynamics). Unifying microphysical measures are defined to quantify different entrainment-mixing mechanisms, and their relationships to the dynamical measures are examined for the purpose of providing physical understanding and developing the parameterization of entrainment-mixing processes in large-scale atmospheric models. For entrainment rate in cumulus clouds, approaches for estimating the fractional entrainment rate are reviewed, including bulk-plume approaches, a mixing fraction approach, and several other approaches. Relationships of entrainment rate to internal cloud properties or external properties are discussed as deterministic parameterizations; entrainment is also parameterized as a stochastic process. Three approaches for estimating entrainment velocity in stratocumulus clouds are also reviewed. Several remaining challenges are explored, including the connection between entrainment-mixing mechanisms and entrainment rate, detailed cloud response to entrainment-mixing in liquid-phase and ice/mixed-phase clouds, secondary entrainment-mixing events, warm rain initiation, detrainment, and effects of initial cloud droplet spectral width and environmental factors. References Ackerman , A. S. , vanZanten , M. C. , Stevens , B. , Savic-Jovcic , V. , Bretherton , C. S. , Chlond , A. , et al. ( 2009 ). Large-Eddy simulations of a drizzling, stratocumulus-topped marine boundary layer . Monthly Weather Review , 137 ( 3 ), 1083 – 1110 . 10.1175/2008MWR2582.1 Web of Science®Google Scholar Andrejczuk , M. , Grabowski , W. W. , Malinowski , S. P. , & Smolarkiewicz , P. K. ( 2009 ). Numerical simulation of cloud–clear air interfacial mixing: Homogeneous versus inhomogeneous mixing . Journal of the Atmospheric Sciences , 66 ( 8 ), 2493 – 2500 . doi:10.1175/2009JAS2956.1. 10.1175/2009JAS2956.1 Web of Science®Google Scholar Arakawa , A. , & Schubert , W. H. ( 1974 ). Interaction of a cumulus cloud ensemble with the large-scale environment, Part I . Journal of the Atmospheric Sciences , 31 ( 3 ), 674 – 701 . doi:10.1175/1520-0469(1974)031<0674:ioacce>2.0.co;2. 10.1175/1520-0469(1974)031<0674:IOACCE>2.0.CO;2 Web of Science®Google Scholar Austin , P. H. , Baker , M. B. , Blyth , A. M. , & Jensen , J. B. ( 1985 ). Small-scale variability in warm continental cumulus clouds . Journal of the Atmospheric Sciences , 42 ( 11 ), 1123 – 1138 . 10.1175/1520-0469(1985)042<1123:ssviwc>2.0.co;2. 10.1175/1520-0469(1985)042<1123:SSVIWC>2.0.CO;2 Web of Science®Google Scholar Baba , Y. ( 2020 ). Shallow convective closure in a spectral cumulus parameterization . Atmospheric Research , 233 , 104707. 10.1016/j.atmosres.2019.104707 Web of Science®Google Scholar Baker , M. B. , Breidenthal , R. E. , Choularton , T. W. , & Latham , J. ( 1984 ). The effects of turbulent mixing in clouds . Journal of the Atmospheric Sciences , 41 (2), 299 – 304 . doi:10.1175/1520-0469(1984)041<0299:TEOTMI> 2 .0.CO;2. 10.1175/1520-0469(1984)041<0299:TEOTMI>2.0.CO;2 Web of Science®Google Scholar Baker , M. B. , Corbin , R. G. , & Latham , J. ( 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 ( 449 ), 581 – 598 . 10.1002/qj.49710644914. 10.1002/qj.49710644914 Web of Science®Google Scholar Baker , M. B. , & Latham , J. ( 1979 ). The evolution of droplet spectra and the rate of production of embryonic raindrops in small cumulus clouds . Journal of the Atmospheric Sciences , 36 ( 8 ), 1612 – 1615 . doi:10.1175/1520-0469(1979)036<1612:TEODSA>2.0.CO;2. 10.1175/1520-0469(1979)036<1612:TEODSA>2.0.CO;2 Web of Science®Google Scholar Beals , M. J. , Fugal , J. P. , Shaw , R. A. , Lu , J. , Spuler , S. M. , & Stith , J. L. ( 2015 ). Holographic measurements of inhomogeneous cloud mixing at the centimeter scale . Science , 350 ( 6256 ), 87 – 90 . 10.1126/science.aab0751. 10.1126/science.aab0751 CASPubMedWeb of Science®Google Scholar Bechtold , P. , Köhler , M. , Jung , T. , Doblas-Reyes , F. , Leutbecher , M. , Rodwell , M. J. , et al. ( 2008 ). Advances in simulating atmospheric variability with the ECMWF model: From synoptic to decadal time-scales . Quarterly Journal of the Royal Meteorological Society , 134 ( 634 ), 1337 – 1351 . 10.1002/qj.289 Web of Science®Google Scholar Becker , T. , Bretherton , C. S. , Hohenegger , C. , & Stevens , B. ( 2018 ). Estimating bulk entrainment with unaggregated and aggregated convection . Geophysical Research Letters , 45 ( 1 ), 455 – 462 . doi:10.1002/2017GL076640. 10.1002/2017GL076640 Web of Science®Google Scholar Bellenger , H. , K. Yoneyama , M. Katsumata , T. Nishizawa , K. Yasunaga , and R. Shirooka ( 2015 ). Observation of moisture tendencies related to shallow convection . Journal of the Atmospheric Sciences , 72 ( 2 ), 305 – 306 . 10.1175/JAS-D-14-0042.1 Web of Science®Google Scholar Bera , S. , Prabha , T. V. , & Grabowski , W. W. ( 2016 ). Observations of monsoon convective cloud microphysics over India and role of entrainment—mixing . Journal of Geophysical Research , 121 ( 16 ), 9767 – 9788 . 10.1002/2016JD025133 Web of Science®Google Scholar Berg , L. K. , Kassianov , E. I. , Long , C. N. , & Mills , D. L. , Jr. ( 2011 ). Surface summertime radiative forcing by shallow cumuli at the Atmospheric Radiation Measurement Southern Great Plains site . Journal of Geophysical Research , 116 , D01202 . https://doi.org/10.1029/2010JD014593 . 10.1029/2010JD014593 Web of Science®Google Scholar Betts , A. ( 1978 ), Convection in the tropics . Quarterly Journal of the Royal Meteorological Society, Suppl. , 105 – 132 . Google Scholar Betts , A. K. ( 1975 ). Parametric interpretation of trade-wind cumulus budget studies . Journal of the Atmospheric Sciences , 32 ( 10 ), 1934 – 1945 . doi:10.1175/1520-0469(1975)032<1934:piotwc>2.0.co;2. 10.1175/1520-0469(1975)032<1934:PIOTWC>2.0.CO;2 Web of Science®Google Scholar Betts , A. K. ( 1983 ). Thermodynamics of mixed stratocumulus layers: Saturation point budgets . Journal of the Atmospheric Sciences , 40 ( 11 ), 2655 – 2670 . 10.1175/1520-0469(1983)040<2655:tomsls>2.0.co;2. 10.1175/1520-0469(1983)040<2655:TOMSLS>2.0.CO;2 Web of Science®Google Scholar Betts , A. K. , & Harshvardhan , H. ( 1987 ). Thermodynamic constraint on the cloud liquid water feedback in climate models . Journal of Geophysical Research , 92 ( D7 ), 8483 – 8485 . 10.1029/JD092iD07p08483. 10.1029/JD092iD07p08483 Web of Science®Google Scholar Blyth , A. M. ( 1993 ). Entrainment in cumulus clouds . Journal of Applied Meteorology , 32 ( 4 ), 626 – 641 . doi: 10.1175/1520-0450(1993)032<0626:eicc>2.0.co;2. 10.1175/1520-0450(1993)032<0626:EICC>2.0.CO;2 Google Scholar Böing , S. J. , Jonker , H. J. J. , Nawara , W. A. , & Siebesma , A. P. ( 2014 ). On the deceiving aspects of mixing diagrams of deep cumulus convection . Journal of the Atmospheric Sciences , 71 ( 1 ), 56 – 68 . 10.1175/JAS-D-13-0127.1. 10.1175/JAS-D-13-0127.1 Web of Science®Google Scholar Böing , S. J. , Siebesma , A. P. , Korpershoek , J. D. , & Jonker , H. J. J. ( 2012 ). Detrainment in deep convection . Geophysical Research Letters , 39 , L20816 . 10.1029/2012GL053735 Web of Science®Google Scholar Bony , S. , & Dufresne , J.-L. ( 2005 ). Marine boundary layer clouds at the heart of tropical cloud feedback uncertainties in climate models . Geophysical Research Letters , 32 ( 20 ), L20806 . doi:10.1029/2005gl023851. 10.1029/2005GL023851 Web of Science®Google Scholar Bretherton , C. S. , McCaa , J. R. , & Grenier , H. ( 2004 ).