• Abrams, T., 1952: The Manual of Photogrammetry. George Banta Publishing, 876 pp.

  • Alexander, C. R., , and J. Wurman, 2005: The 30 May 1998 Spencer, South Dakota, storm. Part I: The structural evolution and environment of the tornadoes. Mon. Wea. Rev., 133, 7296.

    • Search Google Scholar
    • Export Citation
  • Atkins, N. T., , A. McGee, , R. Ducharme, , R. M. Wakimoto, , and J. Wurman, 2012: The LaGrange tornado during VORTEX2. Part II: Photogrammetric analysis of the tornado combined with dual-Doppler radar data. Mon. Wea. Rev., 140, 29392958.

    • Search Google Scholar
    • Export Citation
  • Atlas, D., , R. C. Srivastava, , and R. S. Sekhon, 1973: Doppler radar characteristics of precipitation at vertical incidence. Rev. Geophys. Space Phys., 2, 135.

    • Search Google Scholar
    • Export Citation
  • Bluestein, H. B., 1999: A history of severe-storm-intercept field programs. Wea. Forecasting, 14, 558577.

  • Bluestein, H. B., , J. G. LaDue, , H. Stein, , D. Speheger, , and W. P. Unruh, 1993: Doppler radar wind spectra of supercell tornadoes. Mon. Wea. Rev., 121, 22002221.

    • Search Google Scholar
    • Export Citation
  • Bluestein, H. B., , W. P. Unruh, , D. C. Dowell, , T. A. Hutchinson, , T. M. Crawford, , A. C. Wood, , and H. Stein, 1997: Doppler radar analysis of the Northfield, Texas, tornado of 25 May 1994. Mon. Wea. Rev., 125, 212230.

    • Search Google Scholar
    • Export Citation
  • Bluestein, H. B., , W.-C. Lee, , M. Bell, , C. C. Weiss, , and A. L. Pazmany, 2003: Mobile Doppler radar observations of a tornado in a supercell near Bassett, Nebraska, on 5 June 1999. Part II: Tornado-vortex structure. Mon. Wea. Rev., 131, 29682984.

    • Search Google Scholar
    • Export Citation
  • Bluestein, H. B., , C. C. Weiss, , and A. L. Pazmany, 2004: The vertical structure of a tornado near Happy, Texas, on 5 May 2002: High-resolution, mobile, W-band, Doppler radar observations. Mon. Wea. Rev., 132, 23252337.

    • Search Google Scholar
    • Export Citation
  • Bluestein, H. B., , C. C. Weiss, , M. M. French, , E. M. Holthaus, , R. L. Tanamachi, , S. Frasier, , and A. L. Pazmany, 2007a: The structure of tornadoes near Attica, Kansas, on 12 May 2004: High-resolution, mobile, Doppler radar observations. Mon. Wea. Rev., 135, 475506.

    • Search Google Scholar
    • Export Citation
  • Bluestein, H. B., , M. M. French, , R. L. Tanamachi, , S. Frazier, , K. Hardwick, , F. Junyent, , and A. L. Pazmany, 2007b: Close range observations of tornadoes in supercells made with a dual-polarization, X-band, mobile Doppler radar. Mon. Wea. Rev., 135, 15221543.

    • Search Google Scholar
    • Export Citation
  • Bluestein, H. B., and Coauthors, 2010: A summary of data collected during VORTEX2 by MWR-05XP/TWOLF, UMASS X-pol, and the UMASS W-band radar. Preprints, 25th Conf. on Severe Local Storms, Denver, CO, Amer. Meteor. Soc., P5.4. [Available online at https://ams.confex.com/ams/pdfpapers/176197.pdf.]

  • Brown, R. A., , L. R. Lemon, , and D. W. Burgess, 1978: Tornado detection by pulsed Doppler radar. Mon. Wea. Rev., 106, 2938.

  • Browning, K. A., , and R. Wexler, 1968: The determination of kinematic properties of a wind field using Doppler radar. J. Appl. Meteor., 7, 105113.

    • Search Google Scholar
    • Export Citation
  • Burgess, D. W., , M. A. Magsig, , J. Wurman, , D. C. Dowell, , and Y. Richardson, 2002: Radar observations of the 3 May 1999 Oklahoma City tornado. Wea. Forecasting, 17, 456471.

    • Search Google Scholar
    • Export Citation
  • Carbone, R. E., , M. J. Carpenter, , and C. D. Burghart, 1985: Doppler radar sampling limitations in convective storms. J. Atmos. Oceanic Technol., 2, 357361.

    • Search Google Scholar
    • Export Citation
  • Davies-Jones, R. P., 1986: Tornado dynamics. Thunderstorms: A Social, Scientific and Technological Documentary, Vol. 2, Thunderstorm Morphology and Dynamics, E. Kessler, Ed., University of Oklahoma Press, 197–236.

  • Dowell, D. C., , C. R. Alexander, , J. M. Wurman, , and L. J. Wicker, 2005: Centrifuging of hydrometeors and debris in tornadoes: Radar reflectivity patterns and wind-measurement errors. Mon. Wea. Rev., 133, 15011524.

    • Search Google Scholar
    • Export Citation
  • Eskridge, R. E., , and P. Das, 1976: Effect of a precipitation-driven downdraft on a rotating wind field: A possible trigger mechanism for tornadoes? J. Atmos. Sci., 33, 7084.

    • Search Google Scholar
    • Export Citation
  • Forbes, G. S., 1981: On the reliability of hook echoes as tornado indicators. Mon. Wea. Rev., 109, 14571466.

  • Fujita, T. T., 1981: Tornadoes and downbursts in the context of generalized planetary scales. J. Atmos. Sci., 38, 15111534.

  • Gal-Chen, T., 1978: A method for the initialization of the anelastic equations for matching models with observations. Mon. Wea. Rev., 106, 587606.

    • Search Google Scholar
    • Export Citation
  • Holle, R. L., 1986: Photogrammetry of thunderstorms. Thunderstorms: A Social and Technological Documentary, Vol. 3, Thunderstorm Morphology and Dynamics, E. Kessler, Ed., University of Oklahoma Press, 77–98.

  • Koch, S. E., , M. desJardins, , and P. J. Kocin, 1983: An interactive Barnes objective map analysis scheme for use with satellite and conventional data. J. Climate Appl. Meteor., 22, 14871503.

    • Search Google Scholar
    • Export Citation
  • Kosiba, K., , and J. Wurman, 2010: The three-dimensional axisymmetric wind field structure of the Spencer, South Dakota, 1998 tornado. J. Atmos. Sci., 67, 30743083.

    • Search Google Scholar
    • Export Citation
  • Kosiba, K., , R. J. Trapp, , and J. Wurman, 2008: An analysis of the axisymmetric three-dimensional low level wind field in a tornado using mobile radar observations. Geophys. Res. Lett., 35, L05805, doi:10.1029/2007GL031851.

    • Search Google Scholar
    • Export Citation
  • Lee, W.-C., , and F. D. Marks, 2000: Tropical cyclone kinematic structure retrieved from single Doppler radar observations. Part II: The GBVTD-simplex center finding algorithm. Mon. Wea. Rev., 128, 19251936.

    • Search Google Scholar
    • Export Citation
  • Lee, W.-C., , and J. Wurman, 2005: Diagnosed three-dimensional axisymmetric structure of the Mulhall tornado on 3 May 1999. J. Atmos. Sci., 62, 23732393.

    • Search Google Scholar
    • Export Citation
  • Lee, W.-C., , F. D. Marks, , and R. E. Carbone, 1994: Velocity track display—A technique to extract real-time tropical cyclone circulations using a single airborne Doppler radar. J. Atmos. Oceanic Technol., 11, 337356.

    • Search Google Scholar
    • Export Citation
  • Lee, W.-C., , B. J.-D. Jou, , P.-L. Chang, , and S.-M. Deng, 1999: Tropical cyclone kinematic structure retrieved from single-Doppler radar observations. Part I: Interpretation of Doppler velocity patterns and the GBVTD technique. Mon. Wea. Rev., 127, 24192439.

    • Search Google Scholar
    • Export Citation
  • Lee, W.-C., , B. J.-D. Jou, , P.-L. Chang, , and F. D. Marks, 2000: Tropical cyclone kinematic structure retrieved from single-Doppler radar observations. Part III: Evolution and structure of Typhoon Alex (1987). Mon. Wea. Rev., 128, 39824001.

    • Search Google Scholar
    • Export Citation
  • Lewellen, D. C., , and W. S. Lewellen, 2007a: Near surface intensification of tornado vortices. J. Atmos. Sci., 64, 21762194.

  • Lewellen, D. C., , and W. S. Lewellen, 2007b: Near-surface vortex intensification through corner flow collapse. J. Atmos. Sci., 64, 21952209.

    • Search Google Scholar
    • Export Citation
  • Lewellen, D. C., , W. S. Lewellen, , and J. Xia, 2000: The influence of a local swirl ratio on tornado intensification near the surface. J. Atmos. Sci., 57, 527544.

    • Search Google Scholar
    • Export Citation
  • Lewellen, W. S., , D. C. Lewellen, , and R. I. Sykes, 1997: Large eddy simulation of a tornado’s interaction with the surface. J. Atmos. Sci., 54, 581605.

    • Search Google Scholar
    • Export Citation
  • Majcen, M., , P. Markowski, , Y. Richardson, , D. Dowell, , and J. Wurman, 2008: Multipass objective analyses of Doppler radar data. J. Atmos. Oceanic Technol., 25, 18451858.

    • Search Google Scholar
    • Export Citation
  • Malkus, J., 1952: The slopes of cumulus clouds in relation to external wind shear. Quart. J. Roy. Meteor. Soc., 78, 530542.

  • Marquis, J., , Y. Richardson, , J. Wurman, , and P. Markowski, 2008: Single- and dual-Doppler analysis of a tornadic vortex and surrounding storm-scale flow in the Crowell, Texas, supercell of 30 April 2000. Mon. Wea. Rev., 136, 50175043.

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

  • Oye, R., , C. Mueller, , and S. Smith, 1995: Software for radar translation, visualization, editing, and interpolation. Preprints, 27th Conf. on Radar Meteorology, Vail, CO, Amer. Meteor. Soc., 359–361.

  • Pauley, P. M., , and X. Wu, 1990: The theoretical, discrete, and actual response of the Barnes objective analysis scheme for one- and two-dimensional fields. Mon. Wea. Rev., 118, 11451163.

    • Search Google Scholar
    • Export Citation
  • Rasmussen, E. N., , and J. M. Straka, 2007: Evolution of low-level angular momentum in the 2 June 1995 Dimmitt, Texas, tornado cyclone. J. Atmos. Sci., 64, 13651378.

    • Search Google Scholar
    • Export Citation
  • Rasmussen, E. N., , R. Davies-Jones, , and R. L. Holle, 2003: Terrestrial photogrammetry of weather images acquired in uncontrolled circumstances. J. Atmos. Oceanic Technol., 20, 17901803.

    • Search Google Scholar
    • Export Citation
  • Ryzhkov, A. V., , T. J. Schuur, , D. W. Burgess, , and D. S. Zrnic, 2005: Polarimetric tornado detection. J. Appl. Meteor., 44, 557570.

  • Snow, J. T., 1984: On the formation of particle sheaths in columnar vortices. J. Atmos. Sci., 41, 24772491.

  • Stout, G. E., , and F. A. Huff, 1953: Radar records Illinois tornadogenesis. Bull. Amer. Meteor. Soc., 34, 281284.

  • Tanamachi, R. L., , H. B. Bluestein, , W.-C. Lee, , M. Bell, , and A. Pazmany, 2007: Ground-based velocity track display (GBVTD) analysis of W-band Doppler radar data in a tornado near Stockton, Kansas, on 15 May 1999. Mon. Wea. Rev., 135, 783800.

    • Search Google Scholar
    • Export Citation
  • Wakimoto, R. M., , and B. E. Martner, 1992: Observations of a Colorado tornado. Part II: Combined photogrammetric and Doppler radar analysis. Mon. Wea. Rev., 120, 522543.

    • Search Google Scholar
    • Export Citation
  • Wakimoto, R. M., , H. V. Murphey, , D. C. Dowell, , and H. B. Bluestein, 2003: The Kellerville tornado during VORTEX: Damage survey and Doppler radar analyses. Mon. Wea. Rev., 131, 21972221.

    • Search Google Scholar
    • Export Citation
  • Wakimoto, R. M., , N. T. Atkins, , and J. Wurman, 2011: The LaGrange tornado during VORTEX2. Part I: Photogrammetric analysis of the tornado combined with single-Doppler radar data. Mon. Wea. Rev., 139, 22332258.

    • Search Google Scholar
    • Export Citation
  • Wurman, J., 2001: The DOW mobile multiple-Doppler network. Preprints, 30th Int. Conf. on Radar Meteorology, Munich, Germany, Amer. Meteor. Soc., P3.3. [Available online at https://ams.confex.com/ams/30radar/techprogram/paper_21572.htm.]

  • Wurman, J., , and S. Gill, 2000: Finescale radar observations of the Dimmitt, Texas (2 June 1995), tornado. Mon. Wea. Rev., 128, 21352164.

    • Search Google Scholar
    • Export Citation
  • Wurman, J., , J. M. Straka, , and E. N. Rasmussen, 1996: Fine-scale Doppler radar observations of tornadoes. Science, 272, 17741777.

  • Wurman, J., , J. M. Straka, , E. N. Rasmussen, , M. Randall, , and A. Zahrai, 1997: Design and deployment of a portable, pencil-beam pulsed 3-cm Doppler radar. J. Atmos. Oceanic Technol., 14, 15021512.

    • Search Google Scholar
    • Export Citation
  • Wurman, J., , Y. Richardson, , C. Alexander, , S. Weygandt, , and P. F. Zhang, 2007a: Dual-Doppler and single-Doppler analysis of a tornadic storm undergoing mergers and repeated tornadogenesis. Mon. Wea. Rev., 135, 736758.

    • Search Google Scholar
    • Export Citation
  • Wurman, J., , Y. Richardson, , C. Alexander, , S. Weygandt, , and P. F. Zhang, 2007b: Dual-Doppler analysis of winds and vorticity budget terms near a tornado. Mon. Wea. Rev., 135, 23922405.

    • Search Google Scholar
    • Export Citation
  • Wurman, J., , P. Robinson, , C. Alexander, , and Y. Richardson, 2007c: Low-level winds in tornadoes and potential catastrophic tornado impacts in urban areas. Bull. Amer. Meteor. Soc., 88, 3146.

    • Search Google Scholar
    • Export Citation
  • Wurman, J., , K. Kosiba, , P. Markowski, , Y. Richardson, , D. Dowell, , and P. Robinson, 2010a: Finescale single- and dual-Doppler analysis of tornado intensification, maintenance, and dissipation in the Orleans, Nebraska, supercell. Mon. Wea. Rev., 138, 44394455.

    • Search Google Scholar
    • Export Citation
  • Wurman, J., , L. J. Wicker, , Y. P. Richardson, , E. N. Rasmussen, , P. M. Markowski, , D. Dowell, , D. W. Burgess, , and H. B. Bluestein, 2010b: An overview of the VORTEX2 field campaign. Preprints, 25th Conf. on Severe Local Storms, Denver, CO, Amer. Meteor. Soc., 5.1. [Available online at https://ams.confex.com/ams/25SLS/techprogram/paper_176068.htm.]

  • Zehnder, J. A., , J. Hu, , and A. Razdan, 2007: A stereo photogrammetric technique applied to orographic convection. Mon. Wea. Rev., 135, 22652277.

    • Search Google Scholar
    • Export Citation
  • Zrnic, D., , and M. Istok, 1980: Wind speeds in two tornadic storms and a tornado, deduced from Doppler spectra. J. Appl. Meteor., 19, 14051415.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 30 30 3
PDF Downloads 28 28 1

Finescale Structure of the LaGrange, Wyoming, Tornado during VORTEX2: GBVTD and Photogrammetric Analyses

View More View Less
  • 1 National Center for Atmospheric Research,* Boulder, Colorado
  • | 2 Department of Atmospheric Sciences, Lyndon State College, Lyndonville, Vermont
  • | 3 Center for Severe Weather Research, Boulder, Colorado
© Get Permissions
Restricted access

Abstract

A ground-based velocity track display (GBVTD) analysis of the LaGrange, Wyoming, tornado on 5 June 2009 during the Second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2) is photogrammetrically combined with a series of pictures of the funnel cloud. This analysis reveals the relationship between the vertical velocity, radial and tangential velocities, perturbation pressure, vertical vorticity, and angular momentum with the visual features of the tornado. An intense axial downdraft was evident and was supported by a downward-directed perturbation pressure gradient. The radial inflow at low levels was weak and difficult to retrieve owing to a combination of centrifuging of hydrometeors/debris in the intense circulation and the inability of the radar beam to fully resolve the flow. The tornado was weakening during the analysis period, which was supported by angular momentum being advected out of the tornado.

The availability of a dual-Doppler wind synthesis for this tornadic event provided a unique opportunity to assess the assumptions in the GBVTD methodology. The analysis suggests that the simplified GBVTD equations that have been applied in past studies of tornadoes are not appropriate in the present case. The most accurate retrieval of the radial velocities requires that a higher-order term that is typically neglected be retained. A quantitative assessment of the impact of centrifuging of hydrometeors on the synthesized wind field was attempted. The results suggest that the radial and vertical velocity profile near and within the tornado core can be significantly altered for tornadoes (EF2) that are accompanied by a small radius of maximum wind and relatively weaker low-level inflow.

The National Center for Atmospheric Research is sponsored by the National Science Foundation.

Corresponding author address: Roger M. Wakimoto, NCAR, P.O. Box 3000, Boulder, CO 80307. E-mail: wakimoto@ucar.edu

Abstract

A ground-based velocity track display (GBVTD) analysis of the LaGrange, Wyoming, tornado on 5 June 2009 during the Second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2) is photogrammetrically combined with a series of pictures of the funnel cloud. This analysis reveals the relationship between the vertical velocity, radial and tangential velocities, perturbation pressure, vertical vorticity, and angular momentum with the visual features of the tornado. An intense axial downdraft was evident and was supported by a downward-directed perturbation pressure gradient. The radial inflow at low levels was weak and difficult to retrieve owing to a combination of centrifuging of hydrometeors/debris in the intense circulation and the inability of the radar beam to fully resolve the flow. The tornado was weakening during the analysis period, which was supported by angular momentum being advected out of the tornado.

The availability of a dual-Doppler wind synthesis for this tornadic event provided a unique opportunity to assess the assumptions in the GBVTD methodology. The analysis suggests that the simplified GBVTD equations that have been applied in past studies of tornadoes are not appropriate in the present case. The most accurate retrieval of the radial velocities requires that a higher-order term that is typically neglected be retained. A quantitative assessment of the impact of centrifuging of hydrometeors on the synthesized wind field was attempted. The results suggest that the radial and vertical velocity profile near and within the tornado core can be significantly altered for tornadoes (EF2) that are accompanied by a small radius of maximum wind and relatively weaker low-level inflow.

The National Center for Atmospheric Research is sponsored by the National Science Foundation.

Corresponding author address: Roger M. Wakimoto, NCAR, P.O. Box 3000, Boulder, CO 80307. E-mail: wakimoto@ucar.edu
Save