• Andsager, K., K. V. Beard, and N. F. Laird, 1999: Laboratory measurements of axis ratios for large raindrops. J. Atmos. Sci., 56 , 26732683.

    • Search Google Scholar
    • Export Citation
  • Aydin, K., H. Direskeneli, and T. A. Seliga, 1987: Dual-polarization radar estimation of rainfall parameters compared with ground-based disdrometer measurements: October 29, 1982, central Illinois experiment. IEEE Trans. Geosci. Remote Sens., GE-25 , 834844.

    • Search Google Scholar
    • Export Citation
  • Beard, K. V., and C. Chuang, 1987: A new model for the equilibrium shape of raindrops. J. Atmos. Sci., 44 , 15091524.

  • Bringi, V. N., and V. Chandrasekar, 2001: Polarimetric Doppler Weather Radar: Principles and Applications. Cambridge University Press, 636 pp.

    • Search Google Scholar
    • Export Citation
  • Bringi, V. N., and R. Xiao, 1998: Raindrop axis ratio and size distributions in Florida rainshafts: An assessment of multiparameter radar algorithms. IEEE Trans. Geosci. Remote Sens., 36 , 703715.

    • Search Google Scholar
    • Export Citation
  • Chandrasekar, V., V. N. Bringi, and P. J. Brockwell, 1986: Statistical properties of dual polarized radar signals. Preprints, 23d Conf. on Radar Meteorology, Snowmass, CO, Amer. Meteor. Soc., 154–157.

    • Search Google Scholar
    • Export Citation
  • Gorgucci, E., G. Scarchilli, and V. Chandrasekar, 1999: Specific differential phase shift estimation in the presence of nonuniform rainfall medium along the path. J. Atmos. Oceanic Technol., 16 , 16901697.

    • Search Google Scholar
    • Export Citation
  • Gorgucci, E., . 2000: Measurement of mean raindrop shape from polarimetric radar observations. J. Atmos. Sci., 57 , 34063413.

  • Gunn, R., and G. D. Kinzer, 1949: The terminal velocity of fall for water droplets in stagnant air. J. Meteor., 6 , 243248.

  • Hendry, A., Y. M. M. Antar, and G. C. McCormick, 1987: On the relationship between the degree of preferred orientation in precipitation and dual polarization radar echo characteristics. Radio Sci., 22 , 3750.

    • Search Google Scholar
    • Export Citation
  • Jameson, A. R., 1985: Microphysical interpretation of multiparameter radar measurements in rain. Part III: Interpretation and measurement of propagation differential phase shift between orthogonal linear polarizations. J. Atmos. Sci., 42 , 607614.

    • Search Google Scholar
    • Export Citation
  • Joss, J., and A. Waldvogel, 1967: A raindrop spectrograph with automatic analysis. Pure Appl. Geophys., 68 , 240246.

  • Pruppacher, H. R., and K. V. Beard, 1970: A wind tunnel investigation of the internal circulation and shape of water drops falling at terminal velocity in air. Quart. J. Roy. Meteor. Soc., 96 , 247256.

    • Search Google Scholar
    • Export Citation
  • Sachidananda, M., and D. S. Zrnić, 1987: Rain rate estimates from differential polarization measurements. J. Atmos. Oceanic Technol., 4 , 588598.

    • Search Google Scholar
    • Export Citation
  • Sekhon, R. S., and R. C. Srivastava, 1971: Doppler radar observations of drop-size distributions in a thunderstorm. J. Atmos. Sci., 28 , 983994.

    • Search Google Scholar
    • Export Citation
  • Seliga, T. A., and V. N. Bringi, 1976: Potential use of the radar reflectivity at orthogonal polarizations for measuring precipitation. J. Appl. Meteor., 15 , 6976.

    • Search Google Scholar
    • Export Citation
  • Seliga, T. A., . 1978: Differential reflectivity and differential phase shift: Applications in radar meteorology. Radio Sci., 13 , 271275.

    • Search Google Scholar
    • Export Citation
  • Testud, J., E. L. Bouar, E. Obligis, and M. Ali-Mehenni, 2000: The rain profiling algorithm applied to polarimetric weather radar. J. Atmos. Oceanic Technol., 17 , 332356.

    • Search Google Scholar
    • Export Citation
  • Tokay, A., and K. V. Beard, 1996: A field study of raindrop oscillations. Part I: Observations of size spectra and evaluation of oscillation causes. J. Appl. Meteor., 35 , 16711687.

    • Search Google Scholar
    • Export Citation
  • Ulbrich, C. W., 1983: Natural variations in the analytical form of raindrop size distributions. J. Climate Appl. Meteor., 22 , 17641775.

    • Search Google Scholar
    • Export Citation
  • Ulbrich, C. W., and D. Atlas, 1998: Rainfall microphysics and radar properties: Analysis methods for drop size spectra. J. Appl. Meteor., 37 , 912923.

    • Search Google Scholar
    • Export Citation
  • Willis, P. T., 1984: Functional fits to some observed drop size distribution and parameterization of rain. J. Atmos. Sci., 41 , 16481661.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 592 290 10
PDF Downloads 375 159 11

Estimation of Raindrop Size Distribution Parameters from Polarimetric Radar Measurements

Eugenio GorgucciIstituto di Fisica dell'Atmosfera, Consiglio Nazionale dell Ricerche, Rome, Italy

Search for other papers by Eugenio Gorgucci in
Current site
Google Scholar
PubMed
Close
,
V. ChandrasekarColorado State University, Fort Collins, Colorado

Search for other papers by V. Chandrasekar in
Current site
Google Scholar
PubMed
Close
,
V. N. BringiColorado State University, Fort Collins, Colorado

Search for other papers by V. N. Bringi in
Current site
Google Scholar
PubMed
Close
, and
Gianfranco ScarchilliIstituto di Fisica dell'Atmosfera, Consiglio Nazionale dell Ricerche, Rome, Italy

Search for other papers by Gianfranco Scarchilli in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

Estimation of raindrop size distribution over large spatial and temporal scales has been a long-standing goal of polarimetric radar. Algorithms to estimate the parameters of a gamma raindrop size distribution model from polarimetric radar observations of reflectivity, differential reflectivity, and specific differential phase are developed. Differential reflectivity is the most closely related measurement to a parameter of the drop size distribution, namely, the drop median diameter (D0). The estimator for D0 as well as other parameters are evaluated in the presence of radar measurement errors. It is shown that the drop median diameter can be estimated to an accuracy of 10%, whereas the equivalent intercept parameter can be estimated to an accuracy of 6% in the logarithmic scale. The estimators for the raindrop size distribution parameters are also evaluated using disdrometer data based simulations. The disdrometer based evaluations confirm the accuracy of the algorithms developed herein.

Corresponding author address: Dr. Eugenio Gorgucci, Istituto di Fisica dell'Atmosfera, CNR, Area di Ricerca Roma-Tor Vergata, Via del Fosso del Cavaliere, Rome 100-00133, Italy. Email: gorgucci@radar.ifa.rm.cnr.it

Abstract

Estimation of raindrop size distribution over large spatial and temporal scales has been a long-standing goal of polarimetric radar. Algorithms to estimate the parameters of a gamma raindrop size distribution model from polarimetric radar observations of reflectivity, differential reflectivity, and specific differential phase are developed. Differential reflectivity is the most closely related measurement to a parameter of the drop size distribution, namely, the drop median diameter (D0). The estimator for D0 as well as other parameters are evaluated in the presence of radar measurement errors. It is shown that the drop median diameter can be estimated to an accuracy of 10%, whereas the equivalent intercept parameter can be estimated to an accuracy of 6% in the logarithmic scale. The estimators for the raindrop size distribution parameters are also evaluated using disdrometer data based simulations. The disdrometer based evaluations confirm the accuracy of the algorithms developed herein.

Corresponding author address: Dr. Eugenio Gorgucci, Istituto di Fisica dell'Atmosfera, CNR, Area di Ricerca Roma-Tor Vergata, Via del Fosso del Cavaliere, Rome 100-00133, Italy. Email: gorgucci@radar.ifa.rm.cnr.it

Save