• Battan, L. J., 1977: Rain resulting from melting ice particles. J. Appl. Meteor.,16, 595–604.

  • ——, and J. B. Theiss, 1966: Observations of vertical motions and particle sizes in a thunderstorm. J. Atmos. Sci.,23, 78–87.

  • Chilson, P. B., C. W. Ulbrich, M. F. Larsen, P. Perillat, and J. E. Keener, 1993: Observations of a tropical thunderstorm using a vertically pointing, dual-frequency, collinear beam Doppler radar. J. Atmos. Oceanic Technol.,10, 663–673.

  • Currier, P. E., S. K. Avery, B. B. Balsley, K. S. Gage, and W. L. Eklund, 1992: Combined use of 50 MHz and 915 MHz wind profilers in the estimation of raindrop size distributions. Geophys. Res. Lett.,19, 1017–1020.

  • Dennis, A. S., and W. Hitschfeld, 1990: Advances in precipitation physics following the advent of weather radar. Radar in Meteorology: Battan Memorial and 40th Anniversary Radar Meteorology Conference, D. Atlas, Ed., Amer. Meteor. Soc., 98–108.

  • Drummond, F. J., R. R. Rogers, and S. A. Cohn, 1996: A new look at the melting layer. J. Atmos. Sci.,53, 759–769.

  • Foote, G. B., H. W. Frank, A. J. Heymsfield, and C. G. Wade, 1982:The 22 July 1976 case study: Hail growth. Case Studies of the National Hail Research Experiment, P. Squires and C. A. Knight, Eds., Vol. 2, Hailstorms of the Central High Plains, Colorado Associated University Press, 181–194.

  • Gossard, E. E., 1988: Measuring drop-size distributions in clouds with a clear-air-sensing Doppler radar. J. Atmos. Oceanic Technol.,5, 640–649.

  • ——, R. G. Strauch, and R. R. Rogers, 1990: Evolution of dropsize distributions in liquid precipitation observed by ground-based Doppler radar. J. Atmos. Oceanic Technol.,7, 815–828.

  • Hauser, D., and P. Amayenc, 1980: Drop-size distributions and vertical air motions in a thunderstorm as inferred from Doppler radar observations at vertical incidence. J. Rech. Atmos.,14, 439–455.

  • ——, and ——, 1981: A new method for deducing hydrometeor-size distributions and vertical air motions from Doppler radar measurements at vertical incidence. J. Appl. Meteor.,20, 547–555.

  • ——, and ——, 1983: Exponential size distributions of raindrops and vertical air motions deduced from vertically pointing Doppler radar data using a new method. J. Climate Appl. Meteor.,22, 407–418.

  • ——, and ——, 1984: Raindrop size distributions and vertical air motions as inferred from zenith-pointing Doppler radar with the RONSARD system. Radio Sci.,19, 185–192.

  • Jameson, A. R., and R. C. Srivastava, 1978: Dual-wavelength Doppler radar observations of hail at vertical incidence. J. Appl. Meteor.,17, 1694–1703.

  • Joss, J., and A. Waldvogel, 1970: Raindrop size distributions and Doppler velocities. Preprints, 14th Radar Meteorology Conf., Tucson, AZ, Amer. Meteor. Soc., 153–156.

  • Klaassen, W., 1983: Accurate determination of vertical air velocities in rain by Doppler radar. J. Climate Appl. Meteor.,22, 1788–1793.

  • ——, 1989: Determination of rain intensity from Doppler spectra of vertically scanning radar. J. Atmos. Oceanic Technol.,6, 552–562.

  • Knight, C. A., P. Smith, and C. Wade, 1982: Storm types and some radar reflectivity characteristics. The National Hail Research Experiment, P. Squires and C. A. Knight, Eds., Vol. 1, Hailstorms of the Central High Plains, Colorado Associated University Press, 81–93.

  • Maguire, W. B., II, and S. K. Avery, 1994: Retrieval of raindrop size distributions using two Doppler wind profilers: Model sensitivity testing. J. Appl. Meteor.,33, 1623–1635.

  • Miller, L. J., J. D. Tuttle, and G. B. Foote, 1990: Precipitation production in a large Montana hailstorm: Airflow and particle growth trajectories. J. Atmos. Sci.,47, 1619–1646.

  • Rogers, R. R., 1964: An extension of the Z–R relation for Doppler radar. Preprints, 11th Weather Radar Conf., Boulder, CO, Amer. Meteor. Soc., 158–161.

  • ——, D. Baumgardner, S. A. Ethier, D. A. Carter, and W. L. Eklund, 1993: Comparison of raindrop size distributions measured by radar wind profiler and by airplane. J. Appl. Meteor.,32, 694–699.

  • Sato, T., H. Doji, H. Iwai, I. Kimura, S. Fukao, M. Yamamoto, T. Tsuda, and S. Kato, 1990: Computer processing for deriving drop-size distributions and vertical air velocities from VHF Doppler radar spectra. Radio Sci.,25, 961–973.

  • Srivastava, R. C., 1990: A method for improving rain estimates from vertical-incidence Doppler radar observations. J. Atmos. Oceanic Technol.,7, 769–773.

  • Stewart, R. E., J. D. Marwitz, and J. C. Pace, 1984: Characteristics through the melting layer of stratiform clouds. J. Atmos. Sci.,41, 3227–3237.

  • Thomson, A. D., and R. List, 1996: Raindrop spectra and updraft determination by combining Doppler radar and disdrometer. J. Atmos. Oceanic Technol.,13, 465–476.

  • Ulbrich, C. W., and P. B. Chilson, 1994: Effects of variations in precipitation size distribution and fallspeed law parameters on relations between mean Doppler fallspeed and reflectivity factor. J. Atmos. Oceanic Technol.,11, 1656–1663.

  • Wakasugi, K., A. Mizutani, and M. Matsuo, 1986: Direct method for deriving drop-size distribution and vertical air velocities from VHF Doppler radar spectra. J. Atmos. Oceanic Technol.,3, 623–629.

  • ——, ——, and ——, 1987: Further discussion on deriving drop-size distribution and vertical air velocities directly from VHF Doppler radar spectra. J. Atmos. Oceanic Technol.,4, 170–179.

  • Wilson, J. W., and D. Reum, 1988: The flare echo: Reflectivity and velocity signature. J. Atmos. Oceanic Technol.,5, 197–205.

  • Zawadzki, I., E. Monteiro, and F. Fabry, 1994: The development of drop size distributions in light rain. J. Atmos. Sci.,51, 1100–1113.

  • Zrnić, D. S., 1987: Three-body scattering produces precipitation signature of special diagnostic value. Radio Sci.,22, 76–86.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 154 29 3
PDF Downloads 31 14 0

High-Resolution Measurement of a Hail Region by Vertically Pointing Doppler Radar

View More View Less
  • 1 Department of Physics, University of Toronto, Toronto, Ontario, Canada
Restricted access

Abstract

The precipitation and structure of a hail-producing region embedded within a severe squall line are investigated by combining data simultaneously measured by vertically pointing and volume-scanning Doppler radar. These data are complemented by surface measurements made, at the location of the vertically pointing radar, with a Joss–Waldvogel disdrometer. The vertically pointing radar measured the standard radar data fields (Z, υυ, συ) and the power spectrum of the vertical Doppler velocities. Once the timescale is converted to a spatial scale, based on an estimate of the propagation speed and direction of the storm, the horizontal resolution of the data is less than ∼100 m for Z, υυ, and συ, and less than ∼200 m for power spectra. Spatial resolution in the vertical direction is 250 m for the Z, υυ, συ data and 2.25 km for the power spectra data. The vertical scan measurements were made directly within the weak echo region associated with the hailfall observed at the radar site. These high-resolution measurements reveal large variations in the Doppler velocity power spectra over small horizontal distances (<200 m). Bimodal-shaped power spectra identify hail particles in the edges of the main updraft. The hailfall region was found to contain three separate identifiable areas of hailstones within a horizontal distance (converted from the timescale) of less than 2.5 km.

Corresponding author address: Alan Thomson, Surface Radar Section, Defence Research Establishment Ottawa, 3701 Carling Avenue, Ottawa, ON KIA OZ4, Canada.

Abstract

The precipitation and structure of a hail-producing region embedded within a severe squall line are investigated by combining data simultaneously measured by vertically pointing and volume-scanning Doppler radar. These data are complemented by surface measurements made, at the location of the vertically pointing radar, with a Joss–Waldvogel disdrometer. The vertically pointing radar measured the standard radar data fields (Z, υυ, συ) and the power spectrum of the vertical Doppler velocities. Once the timescale is converted to a spatial scale, based on an estimate of the propagation speed and direction of the storm, the horizontal resolution of the data is less than ∼100 m for Z, υυ, and συ, and less than ∼200 m for power spectra. Spatial resolution in the vertical direction is 250 m for the Z, υυ, συ data and 2.25 km for the power spectra data. The vertical scan measurements were made directly within the weak echo region associated with the hailfall observed at the radar site. These high-resolution measurements reveal large variations in the Doppler velocity power spectra over small horizontal distances (<200 m). Bimodal-shaped power spectra identify hail particles in the edges of the main updraft. The hailfall region was found to contain three separate identifiable areas of hailstones within a horizontal distance (converted from the timescale) of less than 2.5 km.

Corresponding author address: Alan Thomson, Surface Radar Section, Defence Research Establishment Ottawa, 3701 Carling Avenue, Ottawa, ON KIA OZ4, Canada.

Save