Resolution Enhancement Technique Using Range Oversampling

Tian-You Yu School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma

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Guifu Zhang School of Meteorology, University of Oklahoma, Norman, Oklahoma

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Anil B. Chalamalasetti School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma

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Richard J. Doviak NOAA/National Severe Storms Laboratory, Norman, Oklahoma

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Dusan Zrníc NOAA/National Severe Storms Laboratory, Norman, Oklahoma

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Abstract

A novel resolution enhancement technique using range oversampling (RETRO) is presented. Oversampled signals are radar returns from shifted and overlapped resolution volumes in range. It has been recently shown that these signals can be whitened and averaged to optimally reduce the statistical error of weather spectral moment estimations for the case of uniform reflectivity and velocity. Using the same oversampled data, when the resolution is of interest, RETRO can reveal the variation of reflectivity and velocity in range at finescale. The idea is to utilize the redundant information contained in oversampled signals, which come from common regions, to improve the resolution defined by the range weighting function. As a result, oversampled data are optimally combined to produce high-resolution signals for spectral moment estimations. RETRO is demonstrated and verified using numerical simulations for two cases. In the first case, range variation of a tornadic vortex with a diameter of 120 m can be reconstructed by RETRO at a scale of 25 m when a 250-m pulse and an oversampling factor of 10 are used. Application of RETRO to mitigate ground clutter contamination is demonstrated in the second case.

Corresponding author address: T.-Y. Yu, School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK 73019. Email: tyu@ou.edu

Abstract

A novel resolution enhancement technique using range oversampling (RETRO) is presented. Oversampled signals are radar returns from shifted and overlapped resolution volumes in range. It has been recently shown that these signals can be whitened and averaged to optimally reduce the statistical error of weather spectral moment estimations for the case of uniform reflectivity and velocity. Using the same oversampled data, when the resolution is of interest, RETRO can reveal the variation of reflectivity and velocity in range at finescale. The idea is to utilize the redundant information contained in oversampled signals, which come from common regions, to improve the resolution defined by the range weighting function. As a result, oversampled data are optimally combined to produce high-resolution signals for spectral moment estimations. RETRO is demonstrated and verified using numerical simulations for two cases. In the first case, range variation of a tornadic vortex with a diameter of 120 m can be reconstructed by RETRO at a scale of 25 m when a 250-m pulse and an oversampling factor of 10 are used. Application of RETRO to mitigate ground clutter contamination is demonstrated in the second case.

Corresponding author address: T.-Y. Yu, School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK 73019. Email: tyu@ou.edu

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  • Bluestein, H. B., Lee W-C. , Bell M. , Weiss C. C. , and Pazmany A. L. , 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.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bringi, V. N., and Chandrasekar V. , 2001: Polarimetric Doppler Weather Radar Principles and Applications. Cambridge University Press, 636 pp.

    • Search Google Scholar
    • Export Citation
  • Capon, J., 1969: High-resolution frequency–wavenumber spectrum analysis. Proc. IEEE, 57 , 14081419.

  • Cheong, B. L., Hoffman M. W. , Palmer R. D. , Frasier S. J. , and López-Dekker F. J. , 2004: Pulse pair beamforming and the effects of reflectivity field variation on imaging radars. Radio Sci, 39 .RS3014, doi:10.1029/2002RS002843.

    • Search Google Scholar
    • Export Citation
  • Crum, T. D., and Alberty R. L. , 1993: The WSR-88D and the WSR-88D operational support facility. Bull. Amer. Meteor. Soc, 74 , 16691687.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Doviak, R. J., and Zrnić D. S. , 1993: Doppler Radar and Weather Observations. Academic Press, 562 pp.

  • Farrar, M. R., and Smith E. A. , 1992: Spatial resolution enhancement of terrestrial feature using deconvolved SSM/I microwave brightness temperature. IEEE Trans. Geosci. Remote Sens, 30 , 349355.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Haykin, S., 2002: Adaptive Filter Theory. Prentice-Hall, 989 pp.

  • Ivić, I. R., Zrnić D. , and Torres S. M. , 2003: Whitening in range to improve weather radar spectral moment estimates. Part II: Experimental evaluation. J. Atmos. Oceanic Technol, 20 , 14491459.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kudeki, E., and Stitt G. R. , 1987: Frequency domain interferometry: A high-resolution radar technique for studies of atmospheric turbulence. Geophys. Res. Lett, 14 , 198201.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lewis, W., and Perkins P. J. , 1953: Recorded pressure distribution in the outer portion of a tornado vortex. Mon. Wea. Rev, 81 , 379385.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mudukutore, A. S., Chandrasekar V. , and Keeler R. J. , 1998: Pulse compression for weather radars. IEEE Trans. Geosci. Remote Sens, 36 , 125142.

  • Naidu, P. S., 2001: Sensor Array Signal Processing. CRC Press, 472 pp.

  • Palmer, R. D., Gopalam S. , Yu T-Y. , and Fukao S. , 1998: Coherent radar imaging using Capon's method. Radio Sci, 33 , 15851598.

  • Palmer, R. D., Yu T-Y. , and Chilson P. B. , 1999: Range imaging using frequency diversity. Radio Sci, 34 , 14851496.

  • Röttger, J., and Schmidt G. , 1979: High-resolution VHF radar sounding of the troposphere and stratosphere. IEEE Trans. Geosci. Electro, 17 , 182189.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schmidt, G., Rüster R. , and Czechowsky P. , 1979: Complementary code and digital filtering for detection of weak VHF radar signals from the mesosphere. IEEE Trans. Geosci. Electro, 17 , 154161.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Stogryn, A., 1978: Estimates of brightness temperature from scanning radiometer data. IEEE Trans. Antennas Propag, AP-26 , 720726.

  • Torres, S. M., and Zrnić D. , 2003: Whitening in range to improve weather radar spectral moment estimates. Part I: Formulation and simulation. J. Atmos. Oceanic Technol, 20 , 14331448.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wurman, J., 2002: The multiple-vortex structure of a tornado. Wea. Forecasting, 17 , 473505.

  • Yu, T-Y., and Brown W. O. J. , 2004: High-resolution atmospheric profiling using combined spaced antenna and range imaging techniques. Radio Sci, 39 .RS1101, doi:10.1029/2003RS002907.

    • Search Google Scholar
    • Export Citation
  • Yu, T-Y., Palmer R. D. , and Hysell D. L. , 2000: A simulation study of coherent radar imaging. Radio Sci, 35 , 11291141.

  • Zhang, G., Yu T-Y. , and Doviak R. J. , 2005: Angular and range interferometry to refine weather radar resolution. Radio Sci, 40 .RS3013, doi:10.1029/2004RS003125.

    • Search Google Scholar
    • Export Citation
  • Zrnić, D. S., 1975: Simulation of weatherlike Doppler spectra and signals. J. Appl. Meteor, 14 , 619620.

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