• Abdul-Razzak, H., and S. J. Ghan, 2000: A parameterization of aerosol activation: 2. Multiple aerosol types. J. Geophys. Res., 105, 68376844, https://doi.org/10.1029/1999JD901161.

    • Search Google Scholar
    • Export Citation
  • Abdul-Razzak, H., and S. J. Ghan, 2002: A parameterization of aerosol activation 3. Sectional representation. J. Geophys. Res., 107, 4026, https://doi.org/10.1029/2001JD000483.

    • Search Google Scholar
    • Export Citation
  • Abdul-Razzak, H., S. J. Ghan, and C. Rivera-Carpio, 1998: A parameterization of aerosol activation: 1. Single aerosol type. J. Geophys. Res., 103, 61236131, https://doi.org/10.1029/97JD03735.

    • Search Google Scholar
    • Export Citation
  • Ahlm, L., A. Jones, C. W. Stjern, H. Muri, B. Kravitz, and J. E. Kristjánsson, 2017: Marine cloud brightening—As effective without clouds. Atmos. Chem. Phys., 17, 13 07113 087, https://doi.org/10.5194/acp-17-13071-2017.

    • Search Google Scholar
    • Export Citation
  • Ahola, J., and Coauthors, 2022: Parameterising cloud base updraft velocity of marine stratocumuli. Atmos. Chem. Phys., 22, 45234537, https://doi.org/10.5194/acp-22-4523-2022.

    • Search Google Scholar
    • Export Citation
  • Baker, M. B., 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.

    • Search Google Scholar
    • Export Citation
  • Chosson, F., J.-L. Brenguier, and L. Schüller, 2007: Entrainment-mixing and radiative transfer simulation in boundary layer clouds. J. Atmos. Sci., 64, 26702682, https://doi.org/10.1175/JAS3975.1.

    • Search Google Scholar
    • Export Citation
  • Connolly, P. J., G. B. McFiggans, R. Wood, and A. Tsiamis, 2014: Factors determining the most efficient spray distribution for marine cloud brightening. Philos. Trans. Roy. Soc., A372, 20140056, https://doi.org/10.1098/rsta.2014.0056.

    • Search Google Scholar
    • Export Citation
  • Cooper, G., J. Foster, L. Galbraith, S. Jain, A. Neukermans, and B. Ormond, 2014: Preliminary results for salt aerosol production intended for marine cloud brightening, using effervescent spray atomization. Philos. Trans. Roy. Soc., A372, 20140055, https://doi.org/10.1098/rsta.2014.0055.

    • Search Google Scholar
    • Export Citation
  • Diamond, M. S., A. Gettelman, M. D. Lebsock, A. McComiskey, L. M. Russell, R. Wood, and G. Feingold, 2022: To assess marine cloud brightening’s technical feasibility, we need to know what to study—And when to stop. Proc. Natl. Acad. Sci. USA, 119, e2118379119, https://doi.org/10.1073/pnas.2118379119.

    • Search Google Scholar
    • Export Citation
  • Feingold, G., and Z. Levin, 1986: The lognormal fit to raindrop spectra from frontal convective clouds in Israel. J. Climate Appl. Meteor., 25, 13461363, https://doi.org/10.1175/1520-0450(1986)025<1346:TLFTRS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Feingold, G., and B. Morley, 2003: Aerosol hygroscopic properties as measured by lidar and comparison with in situ measurements. J. Geophys. Res., 108, 4327, https://doi.org/10.1029/2002JD002842.

    • Search Google Scholar
    • Export Citation
  • Freud, E., and D. Rosenfeld, 2012: Linear relation between convective cloud drop number concentration and depth for rain initiation. J. Geophys. Res., 117, D02207, https://doi.org/10.1029/2011JD016457.

    • Search Google Scholar
    • Export Citation
  • Ghan, S. J., and R. A. Zaveri, 2007: Parameterization of optical properties for hydrated internally mixed aerosol. J. Geophys. Res., 112, D10201, https://doi.org/10.1029/2006JD007927.

    • Search Google Scholar
    • Export Citation
  • Ghan, S. J., N. Laulainen, R. Easter, R. Wagener, S. Nemesure, E. Chapman, Y. Zhang, and R. Leung, 2001: Evaluation of aerosol direct radiative forcing in mirage. J. Geophys. Res., 106, 52955316, https://doi.org/10.1029/2000JD900502.

    • Search Google Scholar
    • Export Citation
  • Glassmeier, F., F. Hoffmann, J. S. Johnson, T. Yamaguchi, K. S. Carslaw, and G. Feingold, 2021: Aerosol-cloud-climate cooling overestimated by ship-track data. Science, 371, 485489, https://doi.org/10.1126/science.abd3980.

    • Search Google Scholar
    • Export Citation
  • Gulev, S., and Coauthors, 2021: Changing state of the climate system. Climate Change 2021: The Physical Science Basis, Cambridge University Press, 287–422.

  • Hale, G. M., and M. R. Querry, 1973: Optical constants of water in the 200-nm to 200-μm wavelength region. Appl. Opt., 12, 555563, https://doi.org/10.1364/AO.12.000555.

    • 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.

    • Search Google Scholar
    • Export Citation
  • Hoffmann, F., and G. Feingold, 2019: Entrainment and mixing in stratocumulus: Effects of a new explicit subgrid-scale scheme for large-eddy simulations with particle-based microphysics. J. Atmos. Sci., 76, 19551973, https://doi.org/10.1175/JAS-D-18-0318.1.

    • Search Google Scholar
    • Export Citation
  • Hoffmann, F., and G. Feingold, 2021: Cloud microphysical implications for marine cloud brightening: The importance of the seeded particle size distribution. J. Atmos. Sci., 78, 32473262, https://doi.org/10.1175/JAS-D-21-0077.1.

    • 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.

    • 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.

    • Search Google Scholar
    • Export Citation
  • Hoffmann, F., F. Glassmeier, T. Yamaguchi, and G. Feingold, 2020: Liquid water path steady states in stratocumulus: Insights from process-level emulation and mixed-layer theory. J. Atmos. Sci., 77, 22032215, https://doi.org/10.1175/JAS-D-19-0241.1.

    • Search Google Scholar
    • Export Citation
  • Hu, Y., and K. Stamnes, 1993: An accurate parameterization of the radiative properties of water clouds suitable for use in climate models. J. Climate, 6, 728742, https://doi.org/10.1175/1520-0442(1993)006<0728:AAPOTR>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Ivanova, E., Y. Kogan, I. Mazin, and M. Permyakov, 1977: Method of parameterizing the condensation process of droplet growth in numerical models. Izv. Acad. Sci. USSR Atmos. Oceanic Phys., 13, 821826.

    • Search Google Scholar
    • Export Citation
  • Jacobson, M. Z., 2005: Fundamentals of Atmospheric Modeling. 2nd ed. Cambridge University Press, 829 pp.

  • Jaenicke, R., 1993: Tropospheric aerosols. Aerosol–Cloud–Climate Interactions, P. V. Hobbs, Ed., International Geophysics Series, Vol. 54, Elsevier, 131, https://doi.org/10.1016/S0074-6142(08)60210-7.

    • Search Google Scholar
    • Export Citation
  • Jung, C. H., and Y. P. Kim, 2007: Particle extinction coefficient for polydispersed aerosol using a harmonic mean type general approximated solution. Aerosol Sci. Technol., 41, 9941001, https://doi.org/10.1080/02786820701644285.

    • Search Google Scholar
    • Export Citation
  • Khain, A., and Coauthors, 2015: Representation of microphysical processes in cloud-resolving models: Spectral (bin) microphysics versus bulk parameterization. Rev. Geophys., 53, 247322, https://doi.org/10.1002/2014RG000468.

    • 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.

    • Search Google Scholar
    • Export Citation
  • Khvorostyanov, V. I., and J. A. Curry, 1999: A simple analytical model of aerosol properties with account for hygroscopic growth: 2. Scattering and absorption coefficients. J. Geophys. Res., 104, 21632174, https://doi.org/10.1029/98JD02687.

    • Search Google Scholar
    • Export Citation
  • Khvorostyanov, V. I., and J. A. Curry, 2006: Aerosol size spectra and CCN activity spectra: Reconciling the lognormal, algebraic, and power laws. J. Geophys. Res., 111, D12202, https://doi.org/10.1029/2005JD006532.

    • Search Google Scholar
    • Export Citation
  • Khvorostyanov, V. I., and J. A. Curry, 2007: Refinements to the Köhler’s theory of aerosol equilibrium radii, size spectra, and droplet activation: Effects of humidity and insoluble fraction. J. Geophys. Res., 112, D05206, https://doi.org/10.1029/2006JD007672.

    • Search Google Scholar
    • Export Citation
  • Köhler, H., 1936: The nucleus in and the growth of hygroscopic droplets. Trans. Faraday Soc., 32, 11521161, https://doi.org/10.1039/TF9363201152.

    • Search Google Scholar
    • Export Citation
  • Kokhanovsky, A., 2004: Optical properties of terrestrial clouds. Earth-Sci. Rev., 64, 189241, https://doi.org/10.1016/S0012-8252(03)00042-4.

    • Search Google Scholar
    • Export Citation
  • Latham, J., and M. H. Smith, 1990: Effect on global warming of wind-dependent aerosol generation at the ocean surface. Nature, 347, 372373, https://doi.org/10.1038/347372a0.

    • Search Google Scholar
    • Export Citation
  • Latham, J., and Coauthors, 2012: Marine cloud brightening. Philos. Trans. Roy. Soc., A370, 42174262, https://doi.org/10.1098/rsta.2012.0086.

    • 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.

    • Search Google Scholar
    • Export Citation
  • Liu, X., and Coauthors, 2012: Toward a minimal representation of aerosols in climate models: Description and evaluation in the Community Atmosphere Model CAM5. Geosci. Model Dev., 5, 709739, https://doi.org/10.5194/gmd-5-709-2012.

    • Search Google Scholar
    • Export Citation
  • Meador, W. E., and W. R. Weaver, 1980: Two-stream approximations to radiative transfer in planetary atmospheres: A unified description of existing methods and a new improvement. J. Atmos. Sci., 37, 630643, https://doi.org/10.1175/1520-0469(1980)037<0630:TSATRT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Mitchell, D. L., 2000: Parameterization of the Mie extinction and absorption coefficients for water clouds. J. Atmos. Sci., 57, 13111326, https://doi.org/10.1175/1520-0469(2000)057<1311:POTMEA>2.0.CO;2.

    • 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/10.1111/j.2153-3490.1959.tb00003.x.

    • Search Google Scholar
    • Export Citation
  • Morrison, H., J. A. Curry, and V. I. Khvorostyanov, 2005: A new double-moment microphysics parameterization for application in cloud and climate models. Part I: Description. J. Atmos. Sci., 62, 16651677, https://doi.org/10.1175/JAS3446.1.

    • Search Google Scholar
    • Export Citation
  • Nenes, A., S. Ghan, H. Abdul-Razzak, P. Y. Chuang, and J. H. Seinfeld, 2001: Kinetic limitations on cloud droplet formation and impact on cloud albedo. Tellus, 53B, 133149, https://doi.org/10.3402/tellusb.v53i2.16569.

    • Search Google Scholar
    • Export Citation
  • Nussenzveig, H. M., and W. J. Wiscombe, 1980: Efficiency factors in Mie scattering. Phys. Rev. Lett., 45, 14901494, https://doi.org/10.1103/PhysRevLett.45.1490.

    • Search Google Scholar
    • Export Citation
  • Press, W. H., S. A. Teukolsky, W. T. Vetterling, and B. P. Flannery, 1996: Numerical Recipes in Fortran 90: The Art of Parallel Scientific Computing. 2nd ed. Cambridge University Press, 1495 pp.

  • Salter, S., G. Sortino, and J. Latham, 2008: Sea-going hardware for the cloud albedo method of reversing global warming. Philos. Trans. Roy. Soc., A366, 39894006, https://doi.org/10.1098/rsta.2008.0136.

    • Search Google Scholar
    • Export Citation
  • Schwartz, S. E., D. Huang, and D. V. Vladutescu, 2017: High-resolution photography of clouds from the surface: Retrieval of optical depth of thin clouds down to centimeter scales. J. Geophys. Res. Atmos., 122, 28982928, https://doi.org/10.1002/2016JD025384.

    • Search Google Scholar
    • Export Citation
  • Sedunov, Y. S., 1974: Physics of Drop Formation in the Atmosphere. John Wiley and Sons, 244 pp.

  • Seifert, A., and K. D. Beheng, 2006: A two-moment cloud microphysics parameterization for mixed-phase clouds. Part 1: Model description. Meteor. Atmos. Phys., 92, 4566, https://doi.org/10.1007/s00703-005-0112-4.

    • Search Google Scholar
    • Export Citation
  • Shettle, E. P., and R. W. Fenn, 1979: Models for the aerosols of the lower atmosphere and the effects of humidity variations on their optical properties. Air Force Geophysics Laboratory Rep. 214, 94 pp.

  • Slawinska, J., W. W. Grabowski, H. Pawlowska, and A. A. Wyszogrodzki, 2008: Optical properties of shallow convective clouds diagnosed from a bulk-microphysics large-eddy simulation. J. Climate, 21, 16391647, https://doi.org/10.1175/2007JCLI1820.1.

    • Search Google Scholar
    • Export Citation
  • Stevens, B., 2005: Atmospheric moist convection. Annu. Rev. Earth Planet. Sci., 33, 605643, https://doi.org/10.1146/annurev.earth.33.092203.122658.

    • Search Google Scholar
    • Export Citation
  • Tang, I. N., 1997: Thermodynamic and optical properties of mixed-salt aerosols of atmospheric importance. J. Geophys. Res., 102, 18831893, https://doi.org/10.1029/96JD03085.

    • Search Google Scholar
    • Export Citation
  • Twomey, S., 1974: Pollution and the planetary albedo. Atmos. Environ., 8, 12511256, https://doi.org/10.1016/0004-6981(74)90004-3.

  • Vaughan, N. E., and T. M. Lenton, 2011: A review of climate geoengineering proposals. Climatic Change, 109, 745790, https://doi.org/10.1007/s10584-011-0027-7.

    • Search Google Scholar
    • Export Citation
  • Victor, D., D. Zhou, E. Ahmed, P. K. Dadhich, J. Olivier, H.-H. Rogner, K. Sheikho, and M. Yamaguchi, 2014: Introductory chapter. Climate Change 2014: Mitigation of Climate Change, O. Edenhofer, et al., Eds., Cambridge University Press, 111150.

    • Search Google Scholar
    • Export Citation
  • Von der Emde, K., and U. Wacker, 1993: Comments on the relationships between aerosol spectra, equilibrium drop size spectra, and CCN spectra. Beitr. Phys. Atmos., 66, 157162, http://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetail&idt=4021314.

    • 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.

    • Search Google Scholar
    • Export Citation
  • Wiscombe, W. J., 1980: Improved Mie scattering algorithms. Appl. Opt., 19, 15051509, https://doi.org/10.1364/AO.19.001505.

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

  • Wood, R., 2021: Assessing the potential efficacy of marine cloud brightening for cooling Earth using a simple heuristic model. Atmos. Chem. Phys., 21, 14 50714 533, https://doi.org/10.5194/acp-21-14507-2021.

    • Search Google Scholar
    • Export Citation
  • 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.

    • Search Google Scholar
    • Export Citation
  • Zheng, Y., D. Rosenfeld, and Z. Li, 2016: Quantifying cloud base updraft speeds of marine stratocumulus from cloud top radiative cooling. Geophys. Res. Lett., 43, 11 407–11 413, https://doi.org/10.1002/2016GL071185.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 437 437 50
Full Text Views 190 190 11
PDF Downloads 197 197 12

A Parameterization of Interstitial Aerosol Extinction and Its Application to Marine Cloud Brightening

Fabian HoffmannaMeteorologisches Institut, Ludwig-Maximilans-Universität München, Munich, Germany

Search for other papers by Fabian Hoffmann in
Current site
Google Scholar
PubMed
Close
https://orcid.org/0000-0001-5136-0653
,
Bernhard MayeraMeteorologisches Institut, Ludwig-Maximilans-Universität München, Munich, Germany

Search for other papers by Bernhard Mayer in
Current site
Google Scholar
PubMed
Close
, and
Graham FeingoldbChemical Sciences Laboratory, NOAA/Earth System Research Laboratories, Boulder, Colorado

Search for other papers by Graham Feingold in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

Marine cloud brightening (MCB) is a geoengineering approach to counteract climate change by the deliberate seeding of sea salt aerosol particles that, once they activated to cloud droplets, directly increase cloud reflectance and hence global albedo. However, a large fraction of the seeded aerosol may remain interstitial, i.e., unactivated particles among cloud droplets. Because the consideration of interstitial aerosol optical properties usually requires computationally expensive simulations of the entire particle spectrum and direct Mie calculations, we develop a simple parameterization to be used with computationally efficient bulk and even bin cloud microphysical schemes that do not treat the unactivated aerosol explicitly. Using parcel and large-eddy simulations with highly detailed Lagrangian cloud microphysics and direct Mie calculations as a reference, we show that the parameterization captures the variability in the interstitial aerosol extinction successfully. By applying the parameterization to typical MCB cases, we find that the consideration of interstitial aerosol extinction is important for the assessment of MCB in shallow clouds with weak updrafts, in which only a small fraction of aerosol particles is activated to cloud droplets.

Significance Statement

The optical properties of clouds are not only determined by the number and size of cloud droplets. Unactivated aerosol particles, so-called interstitial aerosol, can contribute substantially to the optical thickness of shallow clouds with weak updrafts in aerosol-laden conditions. The consideration of interstitial aerosol optical thickness has been computationally challenging, but the new parameterization presented here allows for an efficient representation in various types of cloud models. The parameterization is shown to be an important addition for the assessment of marine cloud brightening (MCB), a potential geoengineering technique to counteract global warming by increasing the cloud albedo through the deliberate seeding of aerosol.

© 2022 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, fa.hoffmann@lmu.de

Abstract

Marine cloud brightening (MCB) is a geoengineering approach to counteract climate change by the deliberate seeding of sea salt aerosol particles that, once they activated to cloud droplets, directly increase cloud reflectance and hence global albedo. However, a large fraction of the seeded aerosol may remain interstitial, i.e., unactivated particles among cloud droplets. Because the consideration of interstitial aerosol optical properties usually requires computationally expensive simulations of the entire particle spectrum and direct Mie calculations, we develop a simple parameterization to be used with computationally efficient bulk and even bin cloud microphysical schemes that do not treat the unactivated aerosol explicitly. Using parcel and large-eddy simulations with highly detailed Lagrangian cloud microphysics and direct Mie calculations as a reference, we show that the parameterization captures the variability in the interstitial aerosol extinction successfully. By applying the parameterization to typical MCB cases, we find that the consideration of interstitial aerosol extinction is important for the assessment of MCB in shallow clouds with weak updrafts, in which only a small fraction of aerosol particles is activated to cloud droplets.

Significance Statement

The optical properties of clouds are not only determined by the number and size of cloud droplets. Unactivated aerosol particles, so-called interstitial aerosol, can contribute substantially to the optical thickness of shallow clouds with weak updrafts in aerosol-laden conditions. The consideration of interstitial aerosol optical thickness has been computationally challenging, but the new parameterization presented here allows for an efficient representation in various types of cloud models. The parameterization is shown to be an important addition for the assessment of marine cloud brightening (MCB), a potential geoengineering technique to counteract global warming by increasing the cloud albedo through the deliberate seeding of aerosol.

© 2022 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, fa.hoffmann@lmu.de
Save