• Abade, G. C., W. W. Grabowski, and H. Pawlowska, 2018: Broadening of cloud droplet spectra through eddy hopping: Turbulent entraining parcel simulations. J. Atmos. Sci., 75, 33653379, https://doi.org/10.1175/JAS-D-18-0078.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ackerman, A. S., M. P. Kirkpatrick, D. E. Stevens, and O. B. Toon, 2004: The impact of humidity above stratiform clouds on indirect aerosol climate forcing. Nature, 432, 10141017, https://doi.org/10.1038/nature03174.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Andrejczuk, M., J. M. Reisner, B. Henson, M. K. Dubey, and C. A. Jeffery, 2008: The potential impacts of pollution on a nondrizzling stratus deck: Does aerosol number matter more than type? J. Geophys. Res., 113, D19204, https://doi.org/10.1029/2007JD009445.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Arabas, S., A. Jaruga, H. Pawlowska, and W. Grabowski, 2015: libcloudph++ 1.0: A single-moment bulk, double-moment bulk, and particle-based warm-rain microphysics library in C++. Geosci. Model Dev., 8, 16771707, https://doi.org/10.5194/gmd-8-1677-2015.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 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, 16121615, https://doi.org/10.1175/1520-0469(1979)036<1612:TEODSA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Baker, M., R. Corbin, and J. Latham, 1980: The influence of entrainment on the evolution of cloud droplet spectra: I. A model of inhomogeneous mixing. Quart. J. Roy. Meteor. Soc., 106, 581598, https://doi.org/10.1002/qj.49710644914.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Beard, K. V., 1976: Terminal velocity and shape of cloud and precipitation drops aloft. J. Atmos. Sci., 33, 851864, https://doi.org/10.1175/1520-0469(1976)033<0851:TVASOC>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bretherton, C., P. N. Blossey, and J. Uchida, 2007: Cloud droplet sedimentation, entrainment efficiency, and subtropical stratocumulus albedo. Geophys. Res. Lett., 34, L03813, https://doi.org/10.1029/2006GL027648.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Deardorff, J. W., 1980: Stratocumulus-capped mixed layers derived from a three-dimensional model. Bound.-Layer Meteor., 18, 495527, https://doi.org/10.1007/BF00119502.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • de Lozar, A., and J. P. Mellado, 2015: Mixing driven by radiative and evaporative cooling at the stratocumulus top. J. Atmos. Sci., 72, 46814700, https://doi.org/10.1175/JAS-D-15-0087.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • de Lozar, A., and L. Muessle, 2016: Long-resident droplets at the stratocumulus top. Atmos. Chem. Phys., 16, 65636576, https://doi.org/10.5194/acp-16-6563-2016.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • de Lozar, A., and J. P. Mellado, 2017: Reduction of the entrainment velocity by cloud droplet sedimentation in stratocumulus. J. Atmos. Sci., 74, 751765, https://doi.org/10.1175/JAS-D-16-0196.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Feingold, G., and H. Siebert, 2009: Cloud–aerosol interactions from the micro to the cloud scale. Clouds in the Perturbed Climate System: Their Relationship to Energy Balance, Atmospheric Dynamics, and Precipitation, J. Heintzenberg and R. Charlson, Eds., Strüngmann Forum Reports, Vol. 2, MIT Press, 319–338.

    • Crossref
    • Export Citation
  • Feingold, G., W. Cotton, B. Stevens, and A. Frisch, 1996: The relationship between drop in-cloud residence time and drizzle production in numerically simulated stratocumulus clouds. J. Atmos. Sci., 53, 11081122, https://doi.org/10.1175/1520-0469(1996)053<1108:TRBDIC>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gerber, H., G. Frick, S. Malinowski, J. Brenguier, and F. Burnet, 2005: Holes and entrainment in stratocumulus. J. Atmos. Sci., 62, 443459, https://doi.org/10.1175/JAS-3399.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Grabowski, W. W., 2014: Extracting microphysical impacts in large-eddy simulations of shallow convection. J. Atmos. Sci., 71, 44934499, https://doi.org/10.1175/JAS-D-14-0231.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Grabowski, W. W., and G. C. Abade, 2017: Broadening of cloud droplet spectra through eddy hopping: Turbulent adiabatic parcel simulations. J. Atmos. Sci., 74, 14851493, https://doi.org/10.1175/JAS-D-17-0043.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Grabowski, W. W., P. Dziekan, and H. Pawlowska, 2018: Lagrangian condensation microphysics with Twomey CCN activation. Geosci. Model Dev., 11, 103120, https://doi.org/10.5194/gmd-11-103-2018.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Haman, K. E., 2009: Simple approach to dynamics of entrainment interface layers and cloud holes in stratocumulus clouds. Quart. J. Roy. Meteor. Soc., 135, 93100, https://doi.org/10.1002/qj.363.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 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, 14501464, https://doi.org/10.1175/2008JAS2909.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hoffmann, F., 2017: On the limits of Köhler activation theory: How do collision and coalescence affect the activation of aerosols? Atmos. Chem. Phys., 17, 83438356, https://doi.org/10.5194/acp-17-8343-2017.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hoffmann, F., S. Raasch, and Y. Noh, 2015: Entrainment of aerosols and their activation in a shallow cumulus cloud studied with a coupled LCM–LES approach. Atmos. Res., 156, 4357, https://doi.org/10.1016/j.atmosres.2014.12.008.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hoffmann, F., Y. Noh, and S. Raasch, 2017: The route to raindrop formation in a shallow cumulus cloud simulated by a Lagrangian cloud model. J. Atmos. Sci., 74, 21252142, https://doi.org/10.1175/JAS-D-16-0220.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hoffmann, F., T. Yamaguchi, and G. Feingold, 2019: Inhomogeneous mixing in Lagrangian cloud models: Effects on the production of precipitation embryos. J. Atmos. Sci., 76, 113133, https://doi.org/10.1175/JAS-D-18-0087.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jarecka, D., W. W. Grabowski, and H. Pawlowska, 2009: Modeling of subgrid-scale mixing in large-eddy simulation of shallow convection. J. Atmos. Sci., 66, 21252133, https://doi.org/10.1175/2009JAS2929.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jeffery, C. A., 2007: Inhomogeneous cloud evaporation, invariance, and Damköhler number. J. Geophys. Res., 112, D24S21, https://doi.org/10.1029/2007JD008789.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kerstein, A. R., 1988: A linear-eddy model of turbulent scalar transport and mixing. Combust. Sci. Technol., 60, 391421, https://doi.org/10.1080/00102208808923995.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Khairoutdinov, M. F., and D. A. Randall, 2003: Cloud resolving modeling of the ARM summer 1997 IOP: Model formulation, results, uncertainties, and sensitivities. J. Atmos. Sci., 60, 607625, https://doi.org/10.1175/1520-0469(2003)060<0607:CRMOTA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kogan, Y. L., 1991: The simulation of a convective cloud in a 3-D model with explicit microphysics. Part I: Model description and sensitivity experiments. J. Atmos. Sci., 48, 11601189, https://doi.org/10.1175/1520-0469(1991)048<1160:TSOACC>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kogan, Y. L., 2006: Large-eddy simulation of air parcels in stratocumulus clouds: Time scales and spatial variability. J. Atmos. Sci., 63, 952967, https://doi.org/10.1175/JAS3665.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Krueger, S. K., 1993: Linear eddy modeling of entrainment and mixing in stratus clouds. J. Atmos. Sci., 50, 30783090, https://doi.org/10.1175/1520-0469(1993)050<3078:LEMOEA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Krueger, S. K., C.-W. Su, and P. A. McMurtry, 1997: Modeling entrainment and finescale mixing in cumulus clouds. J. Atmos. Sci., 54, 26972712, https://doi.org/10.1175/1520-0469(1997)054<2697:MEAFMI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lehmann, K., H. Siebert, and R. A. Shaw, 2009: Homogeneous and inhomogeneous mixing in cumulus clouds: Dependence on local turbulence structure. J. Atmos. Sci., 66, 36413659, https://doi.org/10.1175/2009JAS3012.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lilly, D. K., 1968: Models of cloud-topped mixed layers under a strong inversion. Quart. J. Roy. Meteor. Soc., 94, 292309, https://doi.org/10.1002/qj.49709440106.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Magaritz-Ronen, L., M. Pinsky, and A. Khain, 2014: Effects of turbulent mixing on the structure and macroscopic properties of stratocumulus clouds demonstrated by a Lagrangian trajectory model. J. Atmos. Sci., 71, 18431862, https://doi.org/10.1175/JAS-D-12-0339.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mellado, J. P., 2017: Cloud-top entrainment in stratocumulus clouds. Annu. Rev. Fluid Mech., 49, 145169, https://doi.org/10.1146/annurev-fluid-010816-060231.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mellado, J. P., C. Bretherton, B. Stevens, and M. Wyant, 2018: DNS and LES for simulating stratocumulus: Better together. J. Adv. Model. Earth Syst., 10, 14211438, https://doi.org/10.1029/2018MS001312.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mordy, W., 1959: Computations of the growth by condensation of a population of cloud droplets. Tellus, 11, 1644, https://doi.org/10.3402/tellusa.v11i1.9283.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nicholls, S., 1989: The structure of radiatively driven convection in stratocumulus. Quart. J. Roy. Meteor. Soc., 115, 487511, https://doi.org/10.1002/qj.49711548704.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pawlowska, H., J. Brenguier, and F. Burnet, 2000: Microphysical properties of stratocumulus clouds. Atmos. Res., 55, 1533, https://doi.org/10.1016/S0169-8095(00)00054-5.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pedersen, J. G., S. P. Malinowski, and W. W. Grabowski, 2016: Resolution and domain-size sensitivity in implicit large-eddy simulation of the stratocumulus-topped boundary layer. J. Adv. Model. Earth Syst., 8, 885903, https://doi.org/10.1002/2015MS000572.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pinsky, M., A. Khain, and A. Korolev, 2016: Theoretical analysis of mixing in liquid clouds—Part 3: Inhomogeneous mixing. Atmos. Chem. Phys., 16, 92739297, https://doi.org/10.5194/acp-16-9273-2016.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Riechelmann, T., Y. Noh, and S. Raasch, 2012: A new method for large-eddy simulations of clouds with Lagrangian droplets including the effects of turbulent collision. New J. Phys., 14, 065008), https://doi.org/10.1088/1367-2630/14/6/065008.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rogers, R. R., and M. K. Yau, 1989: A Short Course in Cloud Physics. Pergamon Press, 293 pp.

  • Rothermel, J., and E. M. Agee, 1980: Aircraft investigation of mesoscale cellular convection during AMTEX 75. J. Atmos. Sci., 37, 10271040, https://doi.org/10.1175/1520-0469(1980)037<1027:AIOMCC>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sagaut, P., 2006: Large Eddy Simulation for Incompressible Flows. Springer, 556 pp.

  • Sato, Y., S.-i. Shima, and H. Tomita, 2018: Numerical convergence of shallow convection cloud field simulations: Comparison between double-moment Eulerian and particle-based Lagrangian microphysics coupled to the same dynamical core. J. Adv. Model. Earth Syst., 10, 14951512, https://doi.org/10.1029/2018MS001285.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shaw, R. A., W. C. Reade, L. R. Collins, and J. Verlinde, 1999: Reply. J. Atmos. Sci., 56, 14371441, https://doi.org/10.1175/1520-0469(1999)056<1437:R>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shima, S.-I., K. Kusano, A. Kawano, T. Sugiyama, and S. Kawahara, 2009: The super-droplet method for the numerical simulation of clouds and precipitation: A particle-based and probabilistic microphysics model coupled with a non-hydrostatic model. Quart. J. Roy. Meteor. Soc., 135, 13071320, https://doi.org/10.1002/qj.441.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shipway, B., and A. Hill, 2012: Diagnosis of systematic differences between multiple parametrizations of warm rain microphysics using a kinematic framework. Quart. J. Roy. Meteor. Soc., 138, 21962211, https://doi.org/10.1002/qj.1913.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sölch, I., and B. Kärcher, 2010: A large-eddy model for cirrus clouds with explicit aerosol and ice microphysics and Lagrangian ice particle tracking. Quart. J. Roy. Meteor. Soc., 136, 20742093, https://doi.org/10.1002/qj.689.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Squires, P., 1952: The growth of cloud drops by condensation. I. General characteristics. Aust. J. Sci. Res., 5, 5986.

  • Stevens, B., and Coauthors, 2003: Dynamics and Chemistry of Marine Stratocumulus—DYCOMS-II. Bull. Amer. Meteor. Soc., 84, 579594, https://doi.org/10.1175/BAMS-84-5-579.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Stevens, B., and Coauthors, 2005: Evaluation of large-eddy simulations via observations of nocturnal marine stratocumulus. Mon. Wea. Rev., 133, 14431462, https://doi.org/10.1175/MWR2930.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Stevens, D., and C. Bretherton, 1999: Effects of resolution on the simulation of stratocumulus entrainment. Quart. J. Roy. Meteor. Soc., 125, 425439, https://doi.org/10.1002/qj.49712555403.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Su, C.-W., S. K. Krueger, P. A. McMurtry, and P. H. Austin, 1998: Linear eddy modeling of droplet spectral evolution during entrainment and mixing in cumulus clouds. Atmos. Res., 47–48, 4158, https://doi.org/10.1016/S0169-8095(98)00039-8.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tölle, M. H., and S. K. Krueger, 2014: Effects of entrainment and mixing on droplet size distributions in warm cumulus clouds. J. Adv. Model. Earth Syst., 6, 281299, https://doi.org/10.1002/2012MS000209.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Vaillancourt, P., M. Yau, P. Bartello, and W. W. Grabowski, 2002: Microscopic approach to cloud droplet growth by condensation. Part II: Turbulence, clustering, and condensational growth. J. Atmos. Sci., 59, 34213435, https://doi.org/10.1175/1520-0469(2002)059<3421:MATCDG>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, S., Q. Wang, and G. Feingold, 2003: Turbulence, condensation, and liquid water transport in numerically simulated nonprecipitating stratocumulus clouds. J. Atmos. Sci., 60, 262278, https://doi.org/10.1175/1520-0469(2003)060<0262:TCALWT>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wood, R., 2012: Stratocumulus clouds. Mon. Wea. Rev., 140, 23732423, https://doi.org/10.1175/MWR-D-11-00121.1.

  • Yamaguchi, T., and D. A. Randall, 2008: Large-eddy simulation of evaporatively driven entrainment in cloud-topped mixed layers. J. Atmos. Sci., 65, 14811504, https://doi.org/10.1175/2007JAS2438.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yamaguchi, T., and D. A. Randall, 2012: Cooling of entrained parcels in a large-eddy simulation. J. Atmos. Sci., 69, 11181136, https://doi.org/10.1175/JAS-D-11-080.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yamaguchi, T., and G. Feingold, 2013: On the size distribution of cloud holes in stratocumulus and their relationship to cloud-top entrainment. Geophys. Res. Lett., 40, 24502454, https://doi.org/10.1002/grl.50442.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 31 31 31
PDF Downloads 20 20 20

Entrainment and Mixing in Stratocumulus: Effects of a New Explicit Subgrid-Scale Scheme for Large-Eddy Simulations with Particle-Based Microphysics

View More View Less
  • 1 Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, and NOAA/Earth System Research Laboratory/Chemical Sciences Division, Boulder, Colorado
  • | 2 NOAA/Earth System Research Laboratory/Chemical Sciences Division, Boulder, Colorado
Restricted access

Abstract

The entrainment and mixing of free-tropospheric air is an essential component of the observed microphysical structure of stratocumulus clouds. Since the relevant scales involved in this process are usually smaller than the grid spacing of typical large-eddy simulations (LESs), their correct representation is difficult. To adequately accommodate these small-scale processes, we apply a recently developed approach that explicitly simulates LES subgrid-scale (SGS) turbulence fluctuation of supersaturation using the one-dimensional linear eddy model. As a result of reduced numerical diffusion and the ability to explicitly represent the SGS distribution of liquid water and supersaturation, entrainment rates tend to be lower in the new approach compared to simulations without it. Furthermore, cloud holes comprising free-tropospheric air with negligible liquid water are shown to persist longer in the stratocumulus deck. Their mixing with the cloud is shown to be more sensitive to the microphysical composition of the cloud as a result of the explicitly resolved inhomogeneous mixing, which is also confirmed analytically. Moreover, inhomogeneous mixing is shown to decrease the droplet concentration and to increase droplet growth significantly, in contrast to previous studies. All in all, the simulations presented can be seen as a first step to bridge the gap between ultra-high-resolution direct numerical simulation and LES, allowing an appropriate representation of small-scale mixing processes, together with the large-scale dynamics of a stratocumulus system.

© 2019 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Fabian Hoffmann, fabian.hoffmann@noaa.gov

Abstract

The entrainment and mixing of free-tropospheric air is an essential component of the observed microphysical structure of stratocumulus clouds. Since the relevant scales involved in this process are usually smaller than the grid spacing of typical large-eddy simulations (LESs), their correct representation is difficult. To adequately accommodate these small-scale processes, we apply a recently developed approach that explicitly simulates LES subgrid-scale (SGS) turbulence fluctuation of supersaturation using the one-dimensional linear eddy model. As a result of reduced numerical diffusion and the ability to explicitly represent the SGS distribution of liquid water and supersaturation, entrainment rates tend to be lower in the new approach compared to simulations without it. Furthermore, cloud holes comprising free-tropospheric air with negligible liquid water are shown to persist longer in the stratocumulus deck. Their mixing with the cloud is shown to be more sensitive to the microphysical composition of the cloud as a result of the explicitly resolved inhomogeneous mixing, which is also confirmed analytically. Moreover, inhomogeneous mixing is shown to decrease the droplet concentration and to increase droplet growth significantly, in contrast to previous studies. All in all, the simulations presented can be seen as a first step to bridge the gap between ultra-high-resolution direct numerical simulation and LES, allowing an appropriate representation of small-scale mixing processes, together with the large-scale dynamics of a stratocumulus system.

© 2019 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Fabian Hoffmann, fabian.hoffmann@noaa.gov
Save