• Atlas, D., R. C. Srivastava, and R. S. Sekhon, 1973: Doppler Radar characteristics of precipitation at vertical incidence. Rev. Geophys., 11 , 135.

    • Search Google Scholar
    • Export Citation
  • Barros, A. P., O. P. Prat, P. Shrestha, F. Y. Testik, and L. F. Bliven, 2008: Revisiting Low and List (1982): Evaluation of raindrop collision parameterizations using laboratory observations and modeling. J. Atmos. Sci., 65 , 29832993.

    • Search Google Scholar
    • Export Citation
  • Bringi, V. N., T. Tang, and V. Chandrasekar, 2004: Evalution of a new polarimetrically based ZR relation. J. Atmos. Oceanic Technol., 21 , 612623.

    • Search Google Scholar
    • Export Citation
  • Feingold, G., Z. Levin, and S. Tzivion, 1991: The evolution of raindrop spectra. Part III: Downdraft generation in an axisymmetrical rainshaft model. J. Atmos. Sci., 48 , 315330.

    • Search Google Scholar
    • Export Citation
  • Gage, K. S., and E. E. Gossard, 2003: Recent developments in observation, modeling, and understanding atmospheric turbulence and waves. Radar and Atmospheric Science: A Collection of Essays in Honor of David Atlas, Meteor. Monogr., No. 30, Amer. Meteor. Soc., 139–150.

    • Search Google Scholar
    • Export Citation
  • Gage, K. S., W. L. Clark, C. R. Williams, and A. Tokay, 2004: Determining reflectivity measurement error from serial measurements using paired disdrometers and profilers. Geophys. Res. Lett., 31 .L23107, doi:10.1029/2004GL020591.

    • Search Google Scholar
    • Export Citation
  • Gossard, E. E., 1994: Measurement of cloud droplet spectra by Doppler radar. J. Atmos. Oceanic Technol., 11 , 712726.

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

  • Hu, Z., and R. C. Srivastava, 1995: Evolution of raindrop size distribution by coalescence, breakup, and evaporation: Theory and observations. J. Atmos. Sci., 52 , 17611783.

    • Search Google Scholar
    • Export Citation
  • Illingworth, A. J., and T. M. Blackman, 2002: The need to represent raindrop size spectra as normalized gamma distributions for the interpretation of polarization radar observations. J. Appl. Meteor., 41 , 286297.

    • Search Google Scholar
    • Export Citation
  • Kumar, S., and D. Ramkrishna, 1996: On the solution of population balance equations by discretization—I. A fixed pivot technique. Chem. Eng. Sci., 51 , 13111332.

    • Search Google Scholar
    • Export Citation
  • List, R., and G. M. McFarquhar, 1990: The evolution of three-peak raindrop size distributions in one-dimensional shaft models. Part I: Single-pulse rain. J. Atmos. Sci., 47 , 29963006.

    • Search Google Scholar
    • Export Citation
  • List, R., N. R. Donaldson, and R. E. Stewart, 1987: Temporal evolution of drop spectra to collisional equilibrium in steady and pulsating rain. J. Atmos. Sci., 44 , 362372.

    • Search Google Scholar
    • Export Citation
  • Low, T. B., and R. List, 1982a: Collision, coalescence and breakup of raindrops. Part I: Experimentally established coalescence efficiencies and fragment size distributions in breakup. J. Atmos. Sci., 39 , 15911606.

    • Search Google Scholar
    • Export Citation
  • Low, T. B., and R. List, 1982b: Collision, coalescence and breakup of raindrops. Part II: Parameterization of fragment size distributions. J. Atmos. Sci., 39 , 16071618.

    • Search Google Scholar
    • Export Citation
  • Lucas, C., A. D. MacKinnon, R. A. Vincent, and P. T. May, 2004: Raindrop size distribution retrievals from a VHF boundary layer radar. J. Atmos. Oceanic Technol., 21 , 4560.

    • Search Google Scholar
    • Export Citation
  • Marshall, J. S., and W. Mc K. Palmer, 1948: The distribution of raindrops with size. J. Meteor., 5 , 165166.

  • McFarquhar, G. M., 2004a: A new representation of collision-induced breakup of raindrops and its implications for the shapes of raindrop size distributions. J. Atmos. Sci., 61 , 777794.

    • Search Google Scholar
    • Export Citation
  • McFarquhar, G. M., 2004b: The effect of raindrop clustering on collision-induced break-up of raindrops. Quart. J. Roy. Meteor. Soc., 130 , 21692190.

    • Search Google Scholar
    • Export Citation
  • McFarquhar, G. M., and R. List, 1991: The evolution of three-peak raindrop size distributions in one-dimensional shaft models. Part II: Multiple-pulse rain. J. Atmos. Sci., 48 , 15871595.

    • Search Google Scholar
    • Export Citation
  • McFarquhar, G. M., and R. List, 1993: The effect of curve fits for the disdrometer calibration on raindrop spectra, rainfall rate, and radar reflectivity. J. Appl. Meteor., 32 , 774782.

    • Search Google Scholar
    • Export Citation
  • McFarquhar, G. M., R. List, D. R. Hudak, R. P. Nissen, J. S. Dobbie, N. P. Tung, and T. S. Kang, 1996: Flux measurements of pulsating rain with a disdrometer and Doppler radar during phase II of the Joint Tropical Rain Experiment in Malaysia. J. Appl. Meteor., 35 , 859874.

    • Search Google Scholar
    • Export Citation
  • McTaggart-Cowan, J. D., and R. List, 1975: Collision and breakup of water drops at terminal velocity. J. Atmos. Sci., 32 , 14011411.

  • Prat, O. P., and A. P. Barros, 2007a: Exploring the use of a column model for the characterization of microphysical processes in warm rain: Results from a homogeneous rainshaft model. Adv. Geosci., 10 , 145152.

    • Search Google Scholar
    • Export Citation
  • Prat, O. P., and A. P. Barros, 2007b: A robust numerical solution of the stochastic collection-breakup equation for warm rain. J. Appl. Meteor. Climatol., 46 , 14801497. Corrigendum, 46, 2014.

    • Search Google Scholar
    • Export Citation
  • Pruppacher, H. R., and J. D. Klett, 1978: Microphysics of Clouds and Precipitation. D. Reidel, 714 pp.

  • Rajopadhyaya, D. K., S. K. Avery, P. T. May, and R. C. Cifelli, 1999: Comparison of precipitation estimation using single- and dual-frequency wind profilers: Simulations and experimental results. J. Atmos. Oceanic Technol., 16 , 165173.

    • Search Google Scholar
    • Export Citation
  • Sauvageot, H., and J. P. Lacaux, 1995: The shape of averaged drop size distributions. J. Atmos. Sci., 52 , 10701083.

  • Schafer, R., S. Avery, P. May, D. Rajopadhyaya, and C. Williams, 2002: Estimation of drop size distributions from dual-frequency wind profiler spectra using deconvolution and a nonlinear least squares fitting technique. J. Atmos. Oceanic Technol., 19 , 864874.

    • Search Google Scholar
    • Export Citation
  • Sheppard, B. E., 1990: Effect of irregularities in the diameter classification of raindrops by the Joss–Waldvogel disdrometer. J. Atmos. Oceanic Technol., 7 , 180183.

    • Search Google Scholar
    • Export Citation
  • Sheppard, B. E., and P. I. Joe, 1994: Comparison of raindrop size distribution measurements by a Joss–Waldvogel disdrometer, a PMS 2DG spectrometer, and a POSS Doppler radar. J. Atmos. Oceanic Technol., 11 , 874887.

    • Search Google Scholar
    • Export Citation
  • Testik, F., and A. P. Barros, 2007: Towards elucidating the microstructure of warm rainfall: A survey. Rev. Geophys., 45 .RG2003, doi:10.1029/2005RG000182.

    • Search Google Scholar
    • Export Citation
  • Tokay, A., D. Wolff, K. Wolff, and P. Bashor, 2003: Rain gauge and disdrometer measurements during the Keys Area Microphysics Project (KAMP). J. Atmos. Oceanic Technol., 20 , 14601477.

    • Search Google Scholar
    • Export Citation
  • Tzivion, S., G. Feingold, and Z. Levin, 1989: The evolution of raindrop spectra. Part II: Collisional collection/breakup and evaporation in a rainshaft. J. Atmos. Sci., 46 , 33123327.

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

    • Search Google Scholar
    • Export Citation
  • Wakasugi, K., A. Mizutani, M. Matsuo, S. Fukao, and S. Kato, 1986: A direct method for deriving drop-size distributions and vertical air velocities from VHF Doppler radar spectra. J. Atmos. Oceanic Technol., 3 , 623629.

    • Search Google Scholar
    • Export Citation
  • Williams, C. R., 2002: Simultaneous ambient air motion and raindrop size distributions retrieved from UHF vertical incident profiler observations. Radio Sci., 37 .1024, doi:10.1029/2000RS002603.

    • Search Google Scholar
    • Export Citation
  • Williams, C. R., A. B. White, K. S. Gage, and F. M. Ralph, 2007: Vertical structure of precipitation and related microphysics observed by NOAA profilers and TRMM during NAME 2004. J. Climate, 20 , 16931712.

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

    • Search Google Scholar
    • Export Citation
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An Intercomparison of Model Simulations and VPR Estimates of the Vertical Structure of Warm Stratiform Rainfall during TWP-ICE

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  • 1 Civil and Environmental Engineering Department, Pratt School of Engineering, Duke University, Durham, North Carolina
  • | 2 Cooperative Institute for Research in Environmental Sciences, University of Colorado, and NOAA/Earth System Research Laboratory, Boulder, Colorado
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Abstract

A model of rain shaft microphysics that solves the stochastic advection–coalescence–breakup equation in an atmospheric column was used to simulate the evolution of a stratiform rainfall event during the Tropical Warm Pool-International Cloud Experiment (TWP-ICE) in Darwin, Australia. For the first time, a dynamic simulation of the evolution of the drop spectra within a one-dimensional rain shaft is performed using realistic boundary conditions retrieved from real rain events. Droplet size distribution (DSD) retrieved from vertically pointing radar (VPR) measurements are sequentially imposed at the top of the rain shaft as boundary conditions to emulate a realistic rain event. Time series of model profiles of integral parameters such as reflectivity, rain rate, and liquid water content were subsequently compared with estimates retrieved from vertically pointing radars and Joss–Waldvogel disdrometer (JWD) observations. Results obtained are within the VPR retrieval uncertainty estimates. Besides evaluating the model’s ability to capture the dynamical evolution of the DSD within the rain shaft, a case study was conducted to assess the potential use of the model as a physically based interpolator to improve radar retrieval at low levels in the atmosphere. Numerical results showed that relative improvements on the order of 90% in the estimation of rain rate and liquid water content can be achieved close to the ground where the VPR estimates are less reliable. These findings raise important questions with regard to the importance of bin resolution and the lack of sensitivity for small raindrop size (<0.03 cm) in the interpretation of JWD data, and the implications of using disdrometer data to calibrate radar algorithms.

Corresponding author address: Dr. Ana P. Barros, Duke University, Box 90287, 2457 CIEMAS Fitzpatrick Bldg., Durham, NC 27708. Email: barros@duke.edu

Abstract

A model of rain shaft microphysics that solves the stochastic advection–coalescence–breakup equation in an atmospheric column was used to simulate the evolution of a stratiform rainfall event during the Tropical Warm Pool-International Cloud Experiment (TWP-ICE) in Darwin, Australia. For the first time, a dynamic simulation of the evolution of the drop spectra within a one-dimensional rain shaft is performed using realistic boundary conditions retrieved from real rain events. Droplet size distribution (DSD) retrieved from vertically pointing radar (VPR) measurements are sequentially imposed at the top of the rain shaft as boundary conditions to emulate a realistic rain event. Time series of model profiles of integral parameters such as reflectivity, rain rate, and liquid water content were subsequently compared with estimates retrieved from vertically pointing radars and Joss–Waldvogel disdrometer (JWD) observations. Results obtained are within the VPR retrieval uncertainty estimates. Besides evaluating the model’s ability to capture the dynamical evolution of the DSD within the rain shaft, a case study was conducted to assess the potential use of the model as a physically based interpolator to improve radar retrieval at low levels in the atmosphere. Numerical results showed that relative improvements on the order of 90% in the estimation of rain rate and liquid water content can be achieved close to the ground where the VPR estimates are less reliable. These findings raise important questions with regard to the importance of bin resolution and the lack of sensitivity for small raindrop size (<0.03 cm) in the interpretation of JWD data, and the implications of using disdrometer data to calibrate radar algorithms.

Corresponding author address: Dr. Ana P. Barros, Duke University, Box 90287, 2457 CIEMAS Fitzpatrick Bldg., Durham, NC 27708. Email: barros@duke.edu

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