• Caylor, I., and Chandrasekar V. , 1996: Time-varying ice crystal orientation in thunderstorms observed with multiparameter radar. IEEE Trans. Geosci. Remote Sens., 34 , 847858.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gorgucci, E., Scarchilli G. , and Chandrasekar V. , 1992: Calibration of radars using polarimetric techniques. IEEE Trans. Geosci. Remote Sens., 30 , 853858.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hubbert, J., Ellis S. , Dixon M. , and Meymaris G. , 2010: Modeling, error analysis, and evaluation of dual-polarization variables obtained from simultaneous horizontal and vertical polarization transmit radar. Part I: Modeling and antenna errors. J. Atmos. Oceanic Technol., 27 , 15831598.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Illingworth, A., and Caylor I. , 1989: Polarization radar estimates of raindrop size spectra and rainfall rates. J. Atmos. Oceanic Technol., 6 , 939949.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rinehart, R., 2004: Radar for Meteorologists. Rinehart Publications, 482 pp.

  • Ryzhkov, A., and Zrnić D. , 2007: Depolarization in ice crystals and its effect on radar polarimetric measurements. J. Atmos. Oceanic Technol., 24 , 12561267.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Vivekanandan, J., Zhang G. , Ellis S. , Rajopadhyaya D. , and Avery S. , 2003: Radar reflectivity calibration using differential propagation phase measurement. Radio Sci., 38 , 8049.

    • Search Google Scholar
    • Export Citation
  • Wang, Y., and Chandrasekar V. , 2006: Polarization isolation requirements for linear dual-polarization weather radar in simultaneous transmission mode of operation. IEEE Trans. Geosci. Remote Sens., 44 , 20192028.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 112 65 2
PDF Downloads 77 28 0

Modeling, Error Analysis, and Evaluation of Dual-Polarization Variables Obtained from Simultaneous Horizontal and Vertical Polarization Transmit Radar. Part II: Experimental Data

View More View Less
  • 1 National Center for Atmospheric Research, * Boulder, Colorado
Restricted access

Abstract

In this second article in a two-part work, the biases of weather radar polarimetric variables from simultaneous horizontally and vertically transmit (SHV) data are investigated. The biases are caused by cross coupling of the simultaneously transmitted vertical (V) and horizontal (H) electric fields. There are two primary causes of cross coupling: 1) the nonzero mean canting angle of the propagation medium (e.g., canted ice crystals) and 2) antenna polarization errors. Given herein are experimental data illustrating both bias sources. In , a model is developed and used to quantify cross coupling and its impact on polarization measurements. Here, in Part II, experimental data from the National Center for Atmospheric Research’s (NCAR’s) S-band dual-polarimetric Doppler radar (S-Pol) and the National Severe Storms Laboratory’s polarimetric Weather Surveillance Radar-1988 Doppler (WSR-88D), KOUN, are used to illustrate biases in differential reflectivity (Zdr). The S-Pol data are unique: both SHV data and fast alternating H and V transmit (FHV) data are gathered in close time proximity, and thus the FHV data provide “truth” for the SHV data. Specifically, the SHV Zdr bias in rain caused by antenna polarization errors is clearly demonstrated by the data. This has not been shown previously in the literature.

Corresponding author address: John C. Hubbert, 3450 Mitchell Lane, National Center for Atmospheric Research, Boulder, CO 80301. Email: hubbert@ucar.edu

Abstract

In this second article in a two-part work, the biases of weather radar polarimetric variables from simultaneous horizontally and vertically transmit (SHV) data are investigated. The biases are caused by cross coupling of the simultaneously transmitted vertical (V) and horizontal (H) electric fields. There are two primary causes of cross coupling: 1) the nonzero mean canting angle of the propagation medium (e.g., canted ice crystals) and 2) antenna polarization errors. Given herein are experimental data illustrating both bias sources. In , a model is developed and used to quantify cross coupling and its impact on polarization measurements. Here, in Part II, experimental data from the National Center for Atmospheric Research’s (NCAR’s) S-band dual-polarimetric Doppler radar (S-Pol) and the National Severe Storms Laboratory’s polarimetric Weather Surveillance Radar-1988 Doppler (WSR-88D), KOUN, are used to illustrate biases in differential reflectivity (Zdr). The S-Pol data are unique: both SHV data and fast alternating H and V transmit (FHV) data are gathered in close time proximity, and thus the FHV data provide “truth” for the SHV data. Specifically, the SHV Zdr bias in rain caused by antenna polarization errors is clearly demonstrated by the data. This has not been shown previously in the literature.

Corresponding author address: John C. Hubbert, 3450 Mitchell Lane, National Center for Atmospheric Research, Boulder, CO 80301. Email: hubbert@ucar.edu

Save