• Cao, Q., and Zhang G. , 2009: Errors in estimating raindrop size distribution parameters employing disdrometer and simulated raindrop spectra. J. Appl. Meteor. Climatol., 48, 406425, doi:10.1175/2008JAMC2026.1.

    • Search Google Scholar
    • Export Citation
  • Carey, L. D., and Petersen W. A. , 2015: Sensitivity of C-band polarimetric radar–based drop size estimates to maximum diameter. J. Appl. Meteor. Climatol., 54, 13521371, doi:10.1175/JAMC-D-14-0079.1.

    • Search Google Scholar
    • Export Citation
  • Cornford, S. G., 1967: Sampling errors in measurements of raindrop and cloud droplet concentrations. Meteor. Mag., 96, 271282.

  • Gertzman, H. S., and Atlas D. , 1977: Sampling errors in the measurement of rain and hail parameters. J. Geophys. Res., 82, 49554966, doi:10.1029/JC082i031p04955.

    • Search Google Scholar
    • Export Citation
  • Johnson, R. W., Kliche D. V. , and Smith P. L. , 2014: Maximum likelihood estimation of gamma parameters for coarsely binned and truncated raindrop size data. Quart. J. Roy. Meteor. Soc., 140, 12451256, doi:10.1002/qj.2209.

    • Search Google Scholar
    • Export Citation
  • Jones, D. M. A., 1992: Raindrop spectra at the ground. J. Appl. Meteor., 31, 12191225, doi:10.1175/1520-0450(1992)031<1219:RSATG>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Joss, J., and Waldvogel A. , 1969: Raindrop size distribution and sampling size errors. J. Atmos. Sci., 26, 566569, doi:10.1175/1520-0469(1969)026<0566:RSDASS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Kliche, D. V., 2007: Raindrop size distribution functions: An empirical approach. Ph.D. dissertation, South Dakota School of Mines and Technology, 211 pp.

  • Kostinski, A. B., and Jameson A. R. , 1997: Fluctuation properties of precipitation. Part I: On deviations of single-size drop counts from the Poisson distribution. J. Atmos. Sci., 54, 21742186, doi:10.1175/1520-0469(1997)054<2174:FPOPPI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Ryzhkov, A. V., Giangrande S. E. , Melnikov V. M. , and Schuur T. J. , 2005: Calibration issues of dual-polarization radar measurements. J. Atmos. Oceanic Technol., 22, 11381155, doi:10.1175/JTECH1772.1.

    • Search Google Scholar
    • Export Citation
  • Smith, P. L., and Kliche D. V. , 2005: The bias in moment estimators for parameters of drop-size distribution functions: Sampling from exponential distributions. J. Appl. Meteor., 44, 11951205, doi:10.1175/JAM2258.1.

    • Search Google Scholar
    • Export Citation
  • Smith, P. L., Liu Z. , and Joss J. , 1993: A study of sampling-variability effects in raindrop size observations. J. Appl. Meteor., 32, 12591269, doi:10.1175/1520-0450(1993)032<1259:ASOSVE>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Smith, P. L., Kliche D. V. , and Johnson R. W. , 2009: The bias and error in moment estimators for parameters of drop size distribution functions: Sampling from gamma distributions. J. Appl. Meteor. Climatol., 48, 21182126, doi:10.1175/2009JAMC2114.1.

    • Search Google Scholar
    • Export Citation
  • Uijlenhoet, R., Porra J. M. , Sempere Torres D. , and Creutin J.-D. , 2006: Analytical solutions to sampling effects in drop size distribution measurements during stationary rainfall. J. Hydrol., 328, 6582, doi:10.1016/j.jhydrol.2005.11.043.

    • Search Google Scholar
    • Export Citation
  • Yuter, S. E., Kingsmill D. E. , Nance L. B. , and Löffler-Mang M. , 2006: Observations of precipitation size and fall speed characteristics within coexisting rain and wet snow. J. Appl. Meteor. Climatol., 45, 14501464, doi:10.1175/JAM2406.1.

    • Search Google Scholar
    • Export Citation
  • Zhang, G., Vivekanandan J. , Brandes E. A. , Meneghini R. , and Kozu T. , 2003: The shape–slope relation in observed gamma raindrop size distributions: Statistical error or useful information? J. Atmos. Oceanic Technol., 20, 11061119, doi:10.1175/1520-0426(2003)020<1106:TSRIOG>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
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Sampling Issues in Estimating Radar Variables from Disdrometer Data

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  • 1 South Dakota School of Mines and Technology, Rapid City, South Dakota
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Abstract

Simulation of sampling from gamma-distributed raindrop populations demonstrates that significant biases and substantial errors can occur in estimates of polarimetric radar variables based on samples of raindrop populations obtained with disdrometers. Biases and RMS errors of 0.5 dB or more in estimates of differential reflectivity Zdr can occur with samples of even a few hundred drops; significant biases and errors also occur in estimates of reflectivity ZH or specific differential phase Kdp. The results indicate that very large samples would be required to obtain adequate representation of the population characteristics for many radar applications. They also suggest that greater attention is needed to the sample sizes in the disdrometer data used in developing polarimetric rainfall-rate estimators or hydrometeor classification algorithms.

Corresponding author address: Paul L. Smith, South Dakota School of Mines and Technology, 501 E. St. Joseph St., Rapid City, SD 57701. E-mail: paul.smith@sdsmt.edu

Abstract

Simulation of sampling from gamma-distributed raindrop populations demonstrates that significant biases and substantial errors can occur in estimates of polarimetric radar variables based on samples of raindrop populations obtained with disdrometers. Biases and RMS errors of 0.5 dB or more in estimates of differential reflectivity Zdr can occur with samples of even a few hundred drops; significant biases and errors also occur in estimates of reflectivity ZH or specific differential phase Kdp. The results indicate that very large samples would be required to obtain adequate representation of the population characteristics for many radar applications. They also suggest that greater attention is needed to the sample sizes in the disdrometer data used in developing polarimetric rainfall-rate estimators or hydrometeor classification algorithms.

Corresponding author address: Paul L. Smith, South Dakota School of Mines and Technology, 501 E. St. Joseph St., Rapid City, SD 57701. E-mail: paul.smith@sdsmt.edu
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