Editorial Type:
Article
Article Type:
Research Article

Cloud Droplet Size Distributions in Low-Level Stratiform Clouds

Natasha L. Miles Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania

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Johannes Verlinde Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania

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Eugene E. Clothiaux Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania

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Print Publication:
01 Jan 2000
DOI:
https://doi.org/10.1175/1520-0469(2000)057<0295:CDSDIL>2.0.CO;2
Page(s):
295–311
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Abstract

A database of stratus cloud droplet (diameter <50 μm) size distribution parameters, derived from in situ data reported in the existing literature, was created, facilitating intercomparison among datasets and quantifying typical values and their variability. From the datasets, which were divided into marine and continental groups, several parameters are presented, including the total number concentration, effective diameter, mean diameter, standard deviation of the droplet diameters about the mean diameter, and liquid water content, as well as the parameters of modified gamma and lognormal distributions. In light of these results, the appropriateness of common assumptions used in remote sensing of cloud droplet size distributions is discussed. For example, vertical profiles of mean diameter, effective diameter, and liquid water content agreed qualitatively with expectations based on the current paradigm of cloud formation. Whereas parcel theory predicts that the standard deviation about the mean diameter should decrease with height, the results illustrated that the standard deviation generally increases with height. A feature common to all marine clouds was their approximately constant total number concentration profiles; however, the total number concentration profiles of continental clouds were highly variable. Without cloud condensation nuclei spectra, classification of clouds into marine and continental groups is based on indirect methods. After reclassification of four sets of measurements in the database, there was a fairly clear dichotomy between marine and continental clouds, but a great deal of variability within each classification.

The relevant applications of this study lie in radiative transfer and climate issues, rather than in cloud formation and dynamics. Techniques that invert remotely sensed measurements into cloud droplet size distributions frequently rely on a priori assumptions, such as constant number concentration profiles and constant spectral width. The results of this paper provide a basis for evaluating the sensitivity of these techniques. In particular, there were large enough differences in observed droplet spectral widths to significantly affect remotely sensed determinations of cloud microphysics.

Corresponding author address: Natasha L. Miles, Department of Meteorology, 503 Walker Building, The Pennsylvania State University, University Park, PA 16802-5013.

Abstract

A database of stratus cloud droplet (diameter <50 μm) size distribution parameters, derived from in situ data reported in the existing literature, was created, facilitating intercomparison among datasets and quantifying typical values and their variability. From the datasets, which were divided into marine and continental groups, several parameters are presented, including the total number concentration, effective diameter, mean diameter, standard deviation of the droplet diameters about the mean diameter, and liquid water content, as well as the parameters of modified gamma and lognormal distributions. In light of these results, the appropriateness of common assumptions used in remote sensing of cloud droplet size distributions is discussed. For example, vertical profiles of mean diameter, effective diameter, and liquid water content agreed qualitatively with expectations based on the current paradigm of cloud formation. Whereas parcel theory predicts that the standard deviation about the mean diameter should decrease with height, the results illustrated that the standard deviation generally increases with height. A feature common to all marine clouds was their approximately constant total number concentration profiles; however, the total number concentration profiles of continental clouds were highly variable. Without cloud condensation nuclei spectra, classification of clouds into marine and continental groups is based on indirect methods. After reclassification of four sets of measurements in the database, there was a fairly clear dichotomy between marine and continental clouds, but a great deal of variability within each classification.

The relevant applications of this study lie in radiative transfer and climate issues, rather than in cloud formation and dynamics. Techniques that invert remotely sensed measurements into cloud droplet size distributions frequently rely on a priori assumptions, such as constant number concentration profiles and constant spectral width. The results of this paper provide a basis for evaluating the sensitivity of these techniques. In particular, there were large enough differences in observed droplet spectral widths to significantly affect remotely sensed determinations of cloud microphysics.

Corresponding author address: Natasha L. Miles, Department of Meteorology, 503 Walker Building, The Pennsylvania State University, University Park, PA 16802-5013.

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  • Akagawa, H., and K. Okada, 1993: Sizes of cloud droplets and cloud droplet residues near stratus cloud base. Atmos. Res.,30, 37–49.

  • Albrecht, B. A., 1989: Aerosols, cloud microphysics and fractional cloudiness. Science,245, 1227–1230.

  • ——, C. S. Bretherton, D. Johnson, W. H. Schubert, and A. S. Frisch, 1995: The Atlantic Stratocumulus Transition Experiment—ASTEX. Bull. Amer. Meteor. Soc.,76, 889–904.

  • Baker, B. A., 1992: Turbulent entrainment and mixing in clouds: A new observational approach. J. Atmos. Sci.,49, 387–404.

  • Baker, M. G., R. G. Corbin, and J. Latham, 1980: The influence of entrainment on the evolution of cloud droplet spectra. Part I: A model of inhomogeneous mixing. Quart. J. Roy. Meteor. Soc.,106, 581–598.

  • Baumgardner, D., 1983: An analysis and comparison of five water drop measuring instruments. J. Climate Appl. Meteor.,22, 891–910.

  • ——, W. Strapp, and J. E. Dye, 1985: Evaluation of the forward scattering spectrometer probe. Part II: Corrections for coincidence and dead-time losses. J. Atmos. Oceanic Technol.,2, 626–632.

  • ——, J. E. Dye, and B. W. Gandrud, 1992: Interpretation of measurements made by the Forward Scattering Spectrometer Probe (FSSP-300) during the airborne arctic stratospheric expedition. J. Geophys. Res.,97, 8035–8046.

  • ——, B. Baker, and K. Weaver, 1993: A technique for the measurement of cloud structure on centimeter scales. J. Atmos. Oceanic Technol.,10, 557–563.

  • Berry, E. X., and R. L. Reinhardt, 1974: An analysis of cloud drop growth by collection. Part II: Single initial distributions. J. Atmos. Sci.,31, 1825–1831.

  • Brenguier, J.-L., 1993: Observations of cloud microstructure at the centimeter scale. J. Appl. Meteor.,32, 783–793.

  • ——, A. R. Rodi, G. Gordon, and P. Wechsler, 1993: Real-time detection of performance degradation of the forward-scattering spectrometer probe. J. Atmos. Oceanic Technol.,10, 27–33.

  • Caughey, S. J., and M. Kitchen, 1984: Simultaneous measurements of the turbulent and microphysical structure of nocturnal stratocumulus cloud. Quart. J. Roy. Meteor. Soc.,110, 13–34.

  • Clark, T. L., 1974: A study in cloud phase parameterization using the gamma distribution. J. Atmos. Sci.,31, 142–155.

  • Dong, X., T. P. Ackerman, E. E. Clothiaux, P. Pilewskie, and Y. Han, 1997: Microphysical and radiative properties of boundary layer stratiform clouds deduced from ground-based measurements. J. Geophys. Res.,102, 23 829–23 843.

  • Duda, D. P., G. L. Stephens, and S. K. Cox, 1991: Microphysical and radiative properties of marine stratocumulus from tethered balloon measurements. J. Appl. Meteor.,30, 170–186.

  • Duynkerke, P. G., H. Zhang, and P. T. Jonker, 1995: Microphysical and turbulent structure of nocturnal stratocumulus as observed during ASTEX. J. Atmos. Sci.,52, 2763–2777.

  • Dye, J. E., and D. Baumgardner, 1984: Evaluation of the Forward Scattering Spectrometer Probe. Part I: Electronic and optical studies. J. Atmos. Oceanic Technol.,1, 329–344.

  • Fairall, C. W., J. E. Hare, and J. B. Snider, 1990: An eight-month sample of marine stratocumulus cloud fraction, albedo, and integrated liquid water. J. Climate,3, 847–864.

  • Feingold, G., and Z. Levin, 1986: The lognormal fit to raindrop spectra from frontal convective clouds in Israel. J. Climate Appl. Meteor.,25, 1346–1363.

  • Fitzgerald, D. E., 1975: Approximation formulas for the equilibrium size of an aerosol particle as a function of its dry size and composition and the ambient relative humidity. J. Appl. Meteor.,14, 1044–1049.

  • Flatau, P. J., G. J. Tripoli, J. Verlinde, and W. R. Cotton, 1989: The CSU-RAMS cloud microphysics module: General theory and code documentation. Tech. Rep. 451, Colorado State University, 88 pp. [Available from Colorado State University, Fort Collins, CO 80521.].

  • Fouquart, Y., J. C. Buriez, and M. Herman, 1990: The influence of clouds on radiation: A climate modeling perspective. Rev. Geophys.,28, 145–166.

  • Fox, N. I., and A. J. Illingworth, 1997: The potential of a spaceborne cloud radar for the detection of stratocumulus clouds. J. Appl. Meteor.,36, 676–687.

  • Frisch, A. S., C. W. Fairall, and J. B. Snider, 1995: Measurement of stratus cloud and drizzle parameters in ASTEX with a Kα-band Doppler radar and a microwave radiometer. J. Atmos. Sci.,52, 2788–2799.

  • ——, G. Feingold, C. W. Fairall, T. Uttal, and J. B. Snider, 1998: On cloud radar and microwave radiometer measurements of stratus cloud liquid water profiles. J. Geophys. Res.,103 (D18), 23 195–23 197.

  • Gerber, H., 1996: Microphysics of marine stratocumulus clouds with two drizzle modes. J. Atmos. Sci.,53, 1649–1662.

  • Gossard, E. E., 1994: Measurement of cloud drop size spectra by Doppler radar. J. Atmos. Oceanic Technol.,11, 712–726.

  • Hayasaka, T., N. Kikuchi, and M. Tanaka, 1995: Absorption of solar radiation by stratocumulus clouds: Aircraft measurements and theoretical calculations. J. Appl. Meteor.,34, 1047–1055.

  • Hu, Y. X., and K. Stamnes, 1993: An accurate parameterization of the radiative properties of water clouds suitable for use in climate models. J. Climate,6, 728–742.

  • Hudson, J. G., and G. Svensson, 1995: Cloud microphysical relationships in California marine stratus. J. Appl. Meteor.,34, 2655–2666.

  • ——, and S. S. Yum, 1997: Droplet spectral broadening in marine stratus. J. Atmos. Sci.,54, 2642–2654.

  • Ichimura, I., M. Fujiwara, and T. Yanase, 1980: The size distribution of cloud drops measured in small maritime cumulus clouds. J. Meteor. Soc. Japan,58, 403–415.

  • Kiehl, J. T., 1994: Sensitivity of a GCM climate simulation to differences in continental vs maritime cloud drop size. J. Geophys. Res.,99 (D11), 23 107–23 115.

  • Knollenberg, R. G., 1976: Three new instruments for cloud physics measurements: The 2-D spectrometer, the Forward Scattering Spectrometer Probe, and the active scattering aerosol spectrometer. Preprints, Int. Conf. on Cloud Physics, Boulder, CO, Amer. Meteor. Soc., 554–561.

  • Korolev, A. V., and I. P. Mazin, 1993: Zones of increased and decreased drop concentration in stratiform clouds. J. Appl. Meteor.,32, 760–773.

  • Levin, L. M., 1958: Functions to represent drop size distributions in clouds: The optical density of clouds. Izv. Akad. Nauk SSSR, Ser. Geofiz.,10, 698–702.

  • Liu, Y., and J. Hallett, 1998: On size distributions of cloud drops growing by condensation: A new conceptual model. J. Atmos. Sci.,55, 527–536.

  • Martin, G. M., D. W. Johnson, and A. Spice, 1994: The measurement and parameterization of effective radius of drops in warm stratocumulus clouds. J. Atmos. Sci.,51, 1823–1842.

  • ——, ——, D. P. Rogers, P. R. Jonas, P. Minnis, and D. A. Hegg, 1995: Observations of the interaction between cumulus clouds and warm stratocumulus clouds in the marine boundary layer during ASTEX. J. Atmos. Sci.,52, 2902–2922.

  • Nakajima, T., and M. D. King, 1990: Determination of the optical thickness and effective particle radius of clouds from reflected solar radiation measurements. Part I: Theory. J. Atmos. Sci.,47, 1878–1893.

  • Nicholls, S., 1984: The dynamics of stratocumulus: Aircraft observations and comparisons with a mixed layer model. Quart. J. Roy. Meteor. Soc.,110, 783–820.

  • Noonkester, V. R., 1984: Droplet spectra observed in marine stratus cloud layers. J. Atmos. Sci.,41, 829–845.

  • Politovich, M. K., 1993: A study of the broadening of droplet size distributions in cumuli. J. Atmos. Sci.,50, 2230–2244.

  • Pruppacher, H. R., and J. D. Klett, 1997: Microphysics of Clouds and Precipitation. 2d ed. Kluwer Academic, 954 pp.

  • Randall, D. A., J. A. Coakley Jr., C. W. Fairall, R. A. Kropfli, and D. H. Lenschow, 1984: Outlook for research on subtropical marine stratiform clouds. Bull. Amer. Meteor. Soc.,65, 1290–1301.

  • Rogers, R. R., and M. K. Yau, 1989: A Short Course in Cloud Physics. 3d ed. Pergamon Press, 293 pp.

  • Ryan, R. T., H. H. Blau Jr., P. C. von Thüna, M. L. Cohen, and G. D. Roberts, 1972: Cloud microstructure as determined by an optical cloud particle spectrometer. J. Appl. Meteor.,11, 149–156.

  • Ryder, P., 1976: The measurement of cloud droplet spectra. Preprints, Int. Conf. on Cloud Physics, Boulder, CO, Amer. Meteor. Soc., 576–580.

  • Slingo, A., 1990: Sensitivity of the Earth’s radiation budget to changes in low clouds. Nature,343, 49–51.

  • ——, R. Brown, and C. L. Wrench, 1982: A field study of nocturnal stratocumulus; III. High resolution radiative and microphysical observations. Quart. J. Roy. Meteor. Soc.,108, 145–165.

  • Stephens, G. L., and C. M. R. Platt, 1987: Aircraft observations of the radiative and microphysical properties of stratocumulus and cumulus cloud fields. J. Climate Appl. Meteor.,26, 1243–1269.

  • Telford, J. W., and S. K. Chai, 1980: A new aspect of condensation theory. Pure Appl. Geophys.,118, 720–742.

  • Ulbrich, C. W., and D. Atlas, 1998: Rainfall microphysics and radar properties: Analysis methods for drop size spectra. J. Appl. Meteor.,37, 912–923.

  • Vali, G., R. D. Kelley, A. Pazmany, and R. E. McIntosh, 1995: Airborne radar and in-situ observations of a shallow stratus with drizzle. Atmos. Res.,38, 361–380.

  • White, A. B., C. W. Fairall, and J. B. Snider, 1995: Surface-based remote sensing of marine boundary-layer cloud properties. J. Atmos. Sci.,52, 2827–2838.

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