Theoretical and Applied Climatology

, Volume 40, Issue 4, pp 209–226 | Cite as

Observations of dynamical and microphysical aspects related to hail formation with the polarimetric Doppler radar Oberpfaffenhofen

  • P. Meischner
Article

Summary

For improving hail suppression strategies much more detailed knowledge on the individual hail formation process within the thermodynamical as well as the dynamical framework of hail producing cloud systems is needed. One possibility to obtain such knowledge on microphysical and dynamical processes simultaneously is with polarimetric Doppler radar measurements. The advanced polarimetric Doppler radar Oberpfaffenhofen, in operation since summer 1987, is described. Its unique capabilities, such as the real time estimation and display of the three Doppler moments reflectivity, Doppler velocity and spectral width as well as polarimetric parameters, such as depolarization ratios and the differential reflectivity are presented. Furthermore, from polarimetric measurements a hail signal is implemented which can be displayed in real time, too.

The microphysical as well as dynamical structure of a squall line has been observed and a conceptual model of the hail formation process within this system is presented, thus illustrating the detailed insights into cloud processes possible with this new radar system.

Keywords

Radar Cloud System Squall Line Suppression Strategy Depolarization Ratio 

Zusammenfassung

Ein neu entwickeltes Wolkenradar, ein polarimetrisches Dopplerradar, ist seit Anfang 1987 in Oberpfaffenhofen in Betrieb. Ein Schwerpunkt der Anwendungen liegt bei der Untersuchung hochreichender Konvektion mit Hagelbildung. Die in Echtzeit berechneten und dargestellten Dopplermomente Reflektivität, Dopplergeschwindigkeit und Spektralbreite der Dopplergeschwindigkeit ermöglichen die Verfolgung der dynamischen und turbulenten Vorgänge. Gleichzeitig können polarimetrische Parameter, wie z. B. Depolarisationsverhältnisse und die differentielle Reflektivität, berechnet und dargestellt werden, die Aufschluß über die im Auflösungsvolumen vorhandenen Hydrometeorarten geben. Insbesondere wurde ein aus polarimetrischen Messungen berechnetes Hagelsignal implementiert. Die Niederschlags- und Hagelentwicklung wurde in einer Squall Line mit dem Radar verfolgt, so daß der Hagelentstehungsprozeß konzeptionell beschrieben werden kann. Eine wesentliche Rolle bei der Hagelentwicklung spielten offenbar isoliert vor der Squall Line entstandene Kumuluswolken, die im mittleren Niveau auf der Vorderseite des Systems eingemischt werden.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Admirat, P., Goyer, G. G., Wojtiw, U., Carte, E. A., Roos, D., Lozowski, E. P., 1985: A Comparative Study of Hailstorms in Switzerland, Canada and South Africa.J. of Climat. 5, 35–51.Google Scholar
  2. Aydin, K. T., Seliga, T., Bringi, V. N., 1984: Differential radar scattering properties of model hail and mixed-phase hydrometeors.Radio Sci. 19, 58–66.Google Scholar
  3. Aydin, K., Seliga, T. A., Balaji, V., 1986: Remote Sensing of Hail with a Dual Linear Polarization Radar.J. Clim. Appl. Meteor. 25, 1475–1484.Google Scholar
  4. Beard, K. V., Jameson, A. R., 1983: Raindrop canting.J. Atmos Sci. 40, 448–454.Google Scholar
  5. Bringi, V. N., Rasmussen, R. M., Vivekanandan, J., 1986a: Multiparameter Radar Measurements in Colorado Convective Storms. Part I: Graupel Melting Studies.J. Atmos. Sci. 43, 2545–2563.Google Scholar
  6. Bringi, V. N., Vivekanandan, J., Tuttle, J. D., 1986b: Multiparameter Radar Measurements in Colorado Convective Storms. Part II: Hail Detection Studies.J. Atmos. Sci. 43, 2564–2577.Google Scholar
  7. Bringi, V. N., Meischner, P., 1988: Remote Sensing of Melting Hail. 10th International Cloud Physics Conference, Bad Homburg, FRG. AMS, Boston, MA., USA.Google Scholar
  8. Dessens, J., 1986: Hail in southwestern France. II: Results of a 30-year hail prevention project with silver iodide seeding from the ground.J. Climate Appl. Meteor. 25, 48–58.Google Scholar
  9. Doviak, R. J., Sirmans, D., Zrnic, D., Walker, G. B., 1978: Considerations for Pulse-Doppler Radar Observations of Severe Thunderstorms.J. Appl. Meteor. 17, 189–205.Google Scholar
  10. Doviak R. J., Zrnic, D. S., 1984:Doppler Radar and Weather Observations. Orlando, San Diego, San Francisco, New York, London, Toronto, Montreal. Sydney, Tokyo, São Paulo: Academic Press Inc., 458 pp.Google Scholar
  11. Dye, J. E., Martner, B. E., Miller, L. J., 1983: Dynamical Microphysical Evolution of a Convective Storm in a Weakly-Sheared Environment. Part I: Microphysical Observations and Interpretations.J. Atmos. Sci. 40, 2083–2109.Google Scholar
  12. English, M., Cheng, L., 1984: Hailstone concentration and size at the ground and at the melting level: Variation of size distribution in Alberta hailstorms. Proc. 9th Intern. Cloud Physics Conf., Tallinn, USSR, August 21–28, 83–86.Google Scholar
  13. Federer, B., Thalmann, B., Jonzel, J., Schiesser, H. H., Hampel, F., Schweingruber, M., Stahel, W., Bader, J., Mezeix, J. F., Doras, N., D'Aubigny, G., Dermegreditchian, G., Vento, D., 1986: Main results of Grossversuch IV.J. Climate Appl. Meteor. 25, 917–957.Google Scholar
  14. Foote, G. B., Frank, H. W., 1983: Case study of a hailstorm in Colorado. Part III: Airflow from triple-Doppler measurements.J. Atmos. Sci. 40, 686–707.Google Scholar
  15. Foote, G. B., 1985: Aspects of Cumulonimbus classification relevant to the Hail problem.J. Rech. Atmos. 19, 61–74.Google Scholar
  16. Frisch, A. S., Strauch, R. G., 1976: Doppler Radar Measurements of Turbulent Kinetic Energy Dissipation Rates in a Northeastern Colorado Convective Storm.J. Appl. Meteor. 15, 1012–1017.Google Scholar
  17. Hendry, A., Antar, Y. M. M., McCormick, L. G., 1987: On the relationship between the degree of preferred orientation in precipitation and dual-polarization radar echo characteristics.Radio Sci. 22, 37–50.Google Scholar
  18. Heymsfield, A. J., Jameson, A. R., Frank, H. W., 1980: Hail Growth Mechanisms in a Colorado Storm. Part II: Hail Formation Processes.J. Atmos. Sci. 37, 1779–1807.Google Scholar
  19. Heymsfield, A. J., 1983: Case Study of a Hailstorm in Colorado. Part IV: Graupel and Hail Growth Mechanisms Deduced through Particle Trajectory Calculations.J. Atmos. Sci. 40, 1482–1509.Google Scholar
  20. Istok, M. J., Doviak, R. J., 1986: Analysis of the Relation Between Doppler Spectral Width and Thunderstorm Turbulence.J. Atmos. Sci. 43, 2199–2214.Google Scholar
  21. Jameson, A. R., 1985: Deducing the microphysical character of precipitation from multiple-parameter polarization measurements.J. Climate Appl. Meteor. 24, 1037–1047.Google Scholar
  22. Johnson, D. B., 1982: The Role of Giant and Ultragiant Aerosol Particles in Warm Rain Initiation.J. Atmos. Sci. 39, 448–460.Google Scholar
  23. Knight, C. A., Foote, G. B., Summers, P. W., 1979: Results of a randomized hail suppression experiment in northeast Colorado. Part IV: Overall discussion and summary in the context of physical research.J. Appl. Meteor. 18, 1629–1639.Google Scholar
  24. Knight, C. A., Squires, P. (ed), 1982:Hailstorms of the Central High Plains. Vol. I:The National Hail Research Experiment. Colorado: Assoc. Univ. Press, 282 pp.Google Scholar
  25. Knight, A., Orville, H. D., Reinking, R. F., Rose, R. L., Smith, P. L., (steering committee), 1987: Overview of Hailswath II. Executive Order No. 75–76, State of South Dakota, USA.Google Scholar
  26. Lilly, D. K., 1979: The Dynamical Structure and Evolution of Thunderstorms and Squall Lines.Ann. Rev. Earth Planet. Sci. 7, 117–161.Google Scholar
  27. Longtin, D. R., Bohren, C. F., Battan, L. J., 1987: Radar Backscattering by Large, Spongy Ice Oblate Spheroids.J. Atmos. Oceanic Technol. 4, 355–358.Google Scholar
  28. Marwitz, J. D., 1973: Hailstorms and hail suppression techniques in the U.S.S.R. 1972.Bull. Amer. Meteor Soc. 54, 313–325.Google Scholar
  29. Meischner, P., Bringi, V. N., Jank, T., 1988: Multiparameter Doppler Radar Observations of a Squall Line with the Polarimetric DFVLR Radar. 10th International Cloud Physics Conference, Bad Homburg, FRG. AMS, Boston, MA., USA.Google Scholar
  30. Moninger, W. R., Kropfli, R. A., Pasqualucci, F., 1984: Scattering properties of hydrometeors as measured by dual-polarization Doppler radar during CCOPE.Radio Sci. 19, 149–156.Google Scholar
  31. Nelson, S. P., 1983: The Influence of Storm Flow Structure on Hail Growth.J. Atmos. Sci. 40, 1965–1983.Google Scholar
  32. Ogura, Y., Liou, M. T., 1980: The structure of a midlatitude squall line: A case study.J. Atmos. Sci. 37, 553–567.Google Scholar
  33. Orlanski, I., Ross, B. B., 1984: The Evolution of an Observed Cold Front. Part II: Mesoscale Dynamics.J. Atmos. Sci. 41, 1669–1703.Google Scholar
  34. Pruppacher, H. R., Pitter, R. L., 1971: A semi-empirical determination of the shape of cloud and raindrops.J. Atmos. Sci. 28, 86–94.Google Scholar
  35. Renick, J. H., 1984: Alberta Hail Project Field Program 1984. Alberta Research Council, Atmospheric Sciences Dept. Report 60 pp.Google Scholar
  36. Rose, R. L., Jameson, T. C., 1986: Evaluation studies of long-term hail damage reduction programs in North Dakota.J. Wea. Modif. 18, 17–20.Google Scholar
  37. Schroth, A. C., Chandra, M. S., Meischner, P. F., 1988: A C-Band Coherent Polarimetric Radar for Propagation and Cloud Physics Research.J. Atmos. Oceanic Technol. 5, 803–822.Google Scholar
  38. Seliga, T. A., Bringi, V. N., 1976: Potential use of radar differential reflectivity measurements at orthogonal polarization for measuring precipitation.J. Appl. Meteor. 15, 69–76.Google Scholar
  39. Seliga, T. A., Aydin, K., Bringi, V. N., 1984: Differential reflectivity and circular depolarization ratio signals and related drop oscillation and propagation effects in rainfall.Radio Sci. 19, 81–89.Google Scholar
  40. Srivastava, R. C., 1987: A Model of Intense Downdrafts Driven by the Melting and Evaporation of Precipitation.J. Atmos. Sci. 44, 1752–1773.Google Scholar
  41. Sigmet, Inc., Woodland Park, 2 Park Dr., Unit No 1, Westford, MA 01886, USA, 1986: Series of documents on the Doppler signal processor of the DFVLR radar.Google Scholar
  42. Stapor, D. P., Pratt, T., 1984: A generalized analysis of dual polarization radar measurements of rain.Radio Sci. 19, 90–98.Google Scholar
  43. Torlaschi, E. R., Humphries, G., Barge, B. L., 1984: Circular polarization for precipitation measurement.Radio Sci. 19, 193–200.Google Scholar
  44. Wang, A. S., Xu, N. Z., 1984:The Studies of Supercell Hailstorms. Proc. 22nd Conf., Rad. Meteorol., Zürich Boston, MA. USA.Google Scholar

Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • P. Meischner
    • 1
  1. 1.Institut für Physik der AtmosphäreDeutsche Forschungsanstalt für Luft- und Raumfahrt e. V.Oberpfaffenhofen, WesslingFederal Republic of Germany

Personalised recommendations