• Bargen, D. W., and Brown R. C. , 1980: Interactive radar velocity unfolding. Preprints, 19th Conf. on Radar Meteorology, Miami, FL, Amer. Meteor. Soc., 278–283.

  • Bergen, W. R., and Albers S. C. , 1988: Two- and three-dimensional de-aliasing of Doppler radar velocities. J. Atmos. Oceanic Technol., 5 , 305319.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Boren, T. A., Cruz J. R. , and Zrnic D. S. , 1986: An artificial intelligence approach to Doppler weather radar velocity dealiasing. Preprints, 23d Conf. on Radar Meteorology, Snowmass, CO, Amer. Meteor. Soc., 107–110.

  • Doviak, R. D., and Zrnic D. S. , 1993: Doppler Radar and Weather Observations. 2d ed. Academic Press, 562 pp.

  • Eilts, M. D., and Smith S. D. , 1990: Efficient dealiasing of Doppler velocities using local environment constraints. J. Atmos. Oceanic Technol., 7 , 118128.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gong, J., Wang L. , and Xu Q. , 2003: A three-step dealiasing method for Doppler velocity data quality control. J. Atmos. Oceanic Technol., 20 , 17381748.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • James, C. N., and Houze R. A. Jr., 2001: A real-time four-dimensional Doppler dealiasing scheme. J. Atmos. Oceanic Technol., 18 , 16741683.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Merritt, M. W., 1984: Automatic velocity dealiasing for real-time applications. Preprints, 22d Conf. on Radar Meteorology, Zurich, Switzerland, Amer. Meteor. Soc., 528–533.

  • Ray, P., and Ziegler C. , 1977: Dealiasing first moment Doppler estimates. J. Appl. Meteor., 16 , 563564.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 23 23 23
PDF Downloads 19 19 19

An Automated 2D Multipass Doppler Radar Velocity Dealiasing Scheme

View More View Less
  • 1 Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma, and NOAA/OAR/National Severe Storms Laboratory, Norman, Oklahoma
Restricted access

Abstract

An automated 2D multipass velocity dealiasing scheme has been developed to correct velocity fields when wind velocities are very large compared to the Nyquist velocity of the weather Doppler radars. The new velocity dealiasing algorithm is based on the horizontal continuity of velocity fields. The algorithm first determines a set of reference radials and gates by finding the weakest wind region. Then from these reference radials and gates, the scheme checks continuities among adjacent gates and corrects for the velocity values with large differences that are close to 2 × (Nyquist velocity). Multiple passes of unfolding are performed and velocities identified as “folded” with low confidence in an earlier pass are not unfolded until a discontinuity is detected with high confidence at a subsequent pass. The new velocity dealiasing scheme does not need external reference velocity data as do many existing algorithms, thus making it more easily applicable. Over 1000 radar volume scans that include tornadoes, hurricanes, and typhoons are selected to test and to evaluate the new algorithm. The results show that the new algorithm is very robust and very computationally efficient. In cases with many data voids, the new algorithm shows improvements over the current WSR-88D operational velocity dealiasing scheme. The new dealiasing algorithm is a simple and stand-alone program that can be a very useful tool to various Doppler radar data users.

Corresponding author address: Jian Zhang, NSSL, 1313 Halley Circle, Norman, OK 73069. Email: jian.zhang@noaa.gov

Abstract

An automated 2D multipass velocity dealiasing scheme has been developed to correct velocity fields when wind velocities are very large compared to the Nyquist velocity of the weather Doppler radars. The new velocity dealiasing algorithm is based on the horizontal continuity of velocity fields. The algorithm first determines a set of reference radials and gates by finding the weakest wind region. Then from these reference radials and gates, the scheme checks continuities among adjacent gates and corrects for the velocity values with large differences that are close to 2 × (Nyquist velocity). Multiple passes of unfolding are performed and velocities identified as “folded” with low confidence in an earlier pass are not unfolded until a discontinuity is detected with high confidence at a subsequent pass. The new velocity dealiasing scheme does not need external reference velocity data as do many existing algorithms, thus making it more easily applicable. Over 1000 radar volume scans that include tornadoes, hurricanes, and typhoons are selected to test and to evaluate the new algorithm. The results show that the new algorithm is very robust and very computationally efficient. In cases with many data voids, the new algorithm shows improvements over the current WSR-88D operational velocity dealiasing scheme. The new dealiasing algorithm is a simple and stand-alone program that can be a very useful tool to various Doppler radar data users.

Corresponding author address: Jian Zhang, NSSL, 1313 Halley Circle, Norman, OK 73069. Email: jian.zhang@noaa.gov

Save