Editorial Type:
Article
Article Type:
Research Article

Calculations Pertaining to Hygroscopic Seeding with Flares

William A. Cooper National Center for Atmospheric Research,* Boulder, Colorado

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Roelof T. Bruintjes National Center for Atmospheric Research,* Boulder, Colorado

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Graeme K. Mather CloudQuest Ltd., Nelspruit, South Africa

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Print Publication:
01 Nov 1997
DOI:
https://doi.org/10.1175/1520-0450(1997)036<1449:CPTHSW>2.0.CO;2
Page(s):
1449–1469
Restricted access

Abstract

Some possible effects of hygroscopic seeding with flares are explored by calculating how such seeding would modify the initial size distribution of cloud droplets and the subsequent evolution of that size distribution by coalescence. To be representative of recent experiments in South Africa, the calculations emphasize the effects of hygroscopic particles that can be produced by flares, instead of the larger particles used in most past hygroscopic-seeding experiments. Parcel calculations representing simultaneous condensation and coalescence suggest that the formation of rain through the warm-rain process can be accelerated significantly by the addition of such hygroscopic particles. Some observations of the effects of hygroscopic material near cloud base support at least the early stages of the calculations. The results suggest that the positive effects being obtained in the South African experiment may occur through such acceleration of the warm-rain process. Possible cloud-seeding applications and climate implications are discussed.

Corresponding author address: William A. Cooper, NCAR, P.O. Box 3000, Boulder CO 80307-3000.

Abstract

Some possible effects of hygroscopic seeding with flares are explored by calculating how such seeding would modify the initial size distribution of cloud droplets and the subsequent evolution of that size distribution by coalescence. To be representative of recent experiments in South Africa, the calculations emphasize the effects of hygroscopic particles that can be produced by flares, instead of the larger particles used in most past hygroscopic-seeding experiments. Parcel calculations representing simultaneous condensation and coalescence suggest that the formation of rain through the warm-rain process can be accelerated significantly by the addition of such hygroscopic particles. Some observations of the effects of hygroscopic material near cloud base support at least the early stages of the calculations. The results suggest that the positive effects being obtained in the South African experiment may occur through such acceleration of the warm-rain process. Possible cloud-seeding applications and climate implications are discussed.

Corresponding author address: William A. Cooper, NCAR, P.O. Box 3000, Boulder CO 80307-3000.

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  • Alofs, D. J., and T.-H. Liu, 1981: Atmospheric measurements of CCN in the supersaturation range 0.013–0.681%. J. Atmos. Sci.,38, 2772–2778.

  • Barratt, E. W., F. P. Parungo, and R. F. Pueschel, 1979: Cloud modification by urban pollution: A physical demonstration. Meteor. Res.,32, 136–149.

  • Battan, L. J., 1963: Relationship between cloud base and initial radar echo. J. Appl. Meteor.,2, 333–336.

  • Beard, K. V., 1976: Terminal velocity and shape of cloud and precipitation drops aloft. J. Atmos. Sci.,33, 851–864.

  • ——, and S. N. Grover, 1974: Numerical collision efficiencies for small raindrops colliding with micron size particles. J. Atmos. Sci.,31, 543–550.

  • ——, and H. T. Ochs III, 1984: Collection and coalescence efficiencies for accretion. J. Geophys. Res.,89, 7165–7169.

  • Berry, E. X, and R. L. Rinehardt, 1974a: An analysis of cloud drop growth by collection: Part I. Double distributions. J. Atmos. Sci.,31, 1814–1824.

  • ——, and ——, 1974b: An analysis of cloud drop growth by collection: Part II. Single initial distributions. J. Atmos. Sci.,31, 1825–1831.

  • Biswas, K. R., and A. S. Dennis, 1971: Formation of a rain shower by salt seeding. J. Appl. Meteor.,10, 780–784.

  • Blyth, A. M., W. A. Cooper, and J. B. Jensen, 1988: A study of the source of entrained air in Montana cumuli. J. Atmos. Sci.,45, 3944–3964.

  • Cash, J. R., and A. H. Karp, 1990: A variable order Runge–Kutta method for initial value problems with rapidly varying right-hand sides. ACM Trans. Math. Software,16, 201–222.

  • Cooper, W. A., 1989: Effects of variable droplet growth histories on droplet size distributions. Part I: Theory. J. Atmos. Sci.,46, 1301–1311.

  • ——, and R. P. Lawson, 1984: Physical interpretation of results from the HIPLEX-1 experiment. J. Climate Appl. Meteor.,23, 523–540.

  • Czys, R. R., 1991: A preliminary appraisal of the natural structure and seedability of updrafts in Midwestern cumulus at the −10°C level. J. Wea. Modif.,23, 1–16.

  • Davis, R. H., 1984: The rate of coagulation of a dilute polydisperse system of sedimenting spheres. J. Fluid Mech.,145, 179–199.

  • Farley, R. D., and C. S. Chen, 1975: A detailed microphysical simulation of hygroscopic seeding on the warm rain process. J. Appl. Meteor.,14, 718–733.

  • Fitzgerald, J. W., 1974: Effect of aerosol composition on cloud droplet size distribution: A numerical study. J. Atmos. Sci.,31, 1358–1367.

  • Fukuta, N., and L. A. Walter, 1970: Kinetics of hydrometeor growth from a vapor-spherical model. J. Atmos. Sci.,27, 1160–1172.

  • Gillespie, D. T., 1975: An exact method for numerically simulating the stochastic coalescence process in a cloud. J. Atmos. Sci.,32, 1977–1989.

  • Golovin, A. M., 1963: The solution of the coagulation equation for cloud dropletsin a rising air current. Bull. Acad. Sci. USSR, Geophys. Ser. (English Transl.),5, 482–487.

  • Hall, W. O., 1980: A detailed microphysical model within a two-dimensional dynamic framework: Model description and preliminary results. J. Atmos. Sci.,37, 2486–2507.

  • Heymsfield, A. J., and M. R. Hjelmfelt, 1984: Processes of hydrometeor development in Oklahoma convective clouds. J. Atmos. Sci.,41, 2811–2835.

  • Hindman, E. E., II, P. V. Hobbs, and L. F. Radke, 1977: Cloud condensation nuclei from a paper mill. Part I: Measured effects on clouds. J. Appl. Meteor.,16, 745–752.

  • Hobbs, P. V., L. F. Radke, and S. E. Shumway, 1970: Cloud condensation nuclei from industrial sources and their apparent influence on precipitation in Washington State. J. Atmos. Sci.,27, 81–89.

  • ——, M. K. Politovich, and L. F. Radke, 1980: The structures of summer convective clouds in eastern Montana. I: Natural clouds. J. Appl. Meteor.,19, 645–663.

  • ——, D. A. Bowdle, and L. F. Radke, 1985a: Particles in the lower troposphere over the High Plains of the United States. Part I: Size distributions, elemental compositions and morphologies. J. Climate Appl. Meteor.,24, 1344–1356.

  • ——, ——, and ——, 1985b: Particles in the lower troposphere over the High Plains of the United States. Part II: Cloud condensation nuclei. J. Climate Appl. Meteor.,24, 1358–1369.

  • Hudson, J. G., 1993: Cloud condensation nuclei near marine cumulus. J. Geophys. Res.,98, 2693–2702.

  • Johnson, D. B., 1982: The role of giant and ultragiant aerosol particles in warm rain initiation. J. Atmos. Sci.,39, 448–460.

  • ——, 1987: On the relative efficiency of coalescence and riming. J. Atmos. Sci.,44, 1671–1680.

  • Klazura, G. E., and C. J. Todd, 1978: A model of hygroscopic seeding in cumulus clouds. J. Appl. Meteor.,17, 1758–1768.

  • Klett, J. D., and M. H. Davis, 1973: Theoretical collision efficiencies of cloud droplets at small Reynolds numbers. J. Atmos. Sci.,30, 107–117.

  • Kovetz, A., and B. Olund, 1969: The effect of coalescence and condensation on rain formation in a cloud of finite vertical extent. J. Atmos. Sci.,26, 1060–1065.

  • Krauss, T. W., R. T. Bruintjes, J. Verlinde, and A. Kahn, 1987: Microphysical and radar observations of seeded and unseeded continental cumulus clouds. J. Climate Appl. Meteor.,26, 585–606.

  • Lee, I. Y., and H. R. Pruppacher, 1977: A comparative study of the growth of cloud droplets by condensation using an air parcel model with and without entrainment. Pure Appl. Geophys.,115, 523–545.

  • List, R. J, 1968: Smithsonian Meteorological Tables. Smithsonian Institute Press, 350 pp.

  • Low, R. D. H., 1969: A generalized equation for the solution effect in droplet growth. J. Atmos. Sci.,26, 608–611.

  • Low, T. B., and R. List, 1982: Collision, coalescence and breakup of raindrops. Part II: Parameterization of fragment size distributions. J. Atmos. Sci.,39, 1607–1618.

  • Mather, G. K., 1991: Coalescence enhancement in large multicell storms caused by emissions from a Kraft paper mill. J. Appl. Meteor.,30, 1134–1146.

  • Ochs, H. T., and K. V. Beard, 1985: Effects of coalescence efficiencies on the formation of precipitation. J. Atmos. Sci.,42, 1451–1454.

  • Paluch, I., 1979: The entrainment mechanism in Colorado cumuli. J. Atmos. Sci.,36, 2467–2478.

  • Press, W. H., S. A. Teukolsky, W. T. Vetterling, and B. P. Flannery, 1992: Numerical Recipes in C. 2d ed. Cambridge University Press, 994 pp.

  • Rogers, J. R., and R. H. Davis, 1990: The effects of van der Waals attractions on cloud droplet growth by coalescence. J. Atmos. Sci.,47, 1075–1080.

  • Rokicki, M. L., and K. C. Young, 1978: The initiation of precipitation in updrafts. J. Appl. Meteor.,17, 745–754.

  • Rosenfeld, D., and W. L. Woodley, 1989: Effects of cloud seeding in West Texas. J. Appl. Meteor.,28, 1050–1080.

  • Schickedanz, P. T., 1974: Inadvertent rain modification as indicated by surface raincells. J. Appl. Meteor.,13, 891–900.

  • Scott, W. D., 1968: Analytic studies of cloud droplet coalescence ]. J. Atmos. Sci.,25, 54–65.

  • ——, and Z. Levin, 1975: A comparison of formulations of stochastic coalescence. J. Atmos. Sci.,32, 843–847.

  • Srivastava, R. C., 1989: Growth of cloud drops by condensation: A criticism of currently accepted theory and a new approach. J. Atmos. Sci.,46, 869–887.

  • Stith, J. L., A. G. Detwiler, R. F. Reinking, and Paul L. Smith, 1990: Investigating transport, mixing and the formation of ice in cumuli with gaseous tracer techniques. Atmos. Res.,25, 195–216.

  • Telford, J. W., and S. K. Chai, 1980: A new aspect of condensation theory. Pure Appl. Geophys.,119, 720–742.

  • Tzivion, S., T. Reisin, and Z. Levin, 1994: Numerical simulation of hygroscopic seeding in a convective cloud. J. Atmos. Sci.,33, 252–267.

  • Weast, R. C., Ed., 1966: Handbook of chemistry and physics. The Chemical Rubber Co., Cleveland, Ohio, 1838 pp. [Available from The Chemical Rubber Co., 2310 Superior Avenue, Cleveland, OH 44114.].

  • Weil, J. C., R. P. Lawson, and A. R. Rodi, 1993: Relative dispersion of ice crystals in seeded cumuli. J. Appl. Meteor.,32, 1055–1073.

  • Young, K. C., 1993: Effects of simplifications of the Kohler equation on the activation of CCN in an updraft. J. Atmos. Sci.,50, 2314–2317.

  • ——, and A. J. Warren, 1992: A reexamination of the derivation of the equilibrium supersaturation curve for soluble particles. J. Atmos. Sci.,49, 1138–1143.

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