Characteristics of Chaff Echoes Observed by X-band Dual Polarization Radar

X-밴드 이중편파레이더에서 관측된 채프에코의 특성

  • Received : 2012.10.09
  • Accepted : 2012.12.20
  • Published : 2013.02.28


To effectively remove chaff echoes, which are often misidentified as precipitation echoes on weather radars, this study examines the relationship between the radar reflectivity and each of dual polarimetric parameters. The dual polarimetric parameters are collected only for the echo areas identified as chaff echoes on the NIMR X-band dual polarization radar. Overall, the polarimetric parameters (i.e., reflectivity, differential reflectivity, cross correlation coefficient, standard deviation of differential reflectivity and specific differential phase) for chaff echoes have a wider range of values than those for precipitation echoes and the chaff filaments tend to be horizontally oriented to radar beams. There appears to be a considerable overlap in the cross correlation coefficient range of chaff and precipitation echoes since some precipitation echoes have cross correlation coefficient lower than 0.8. Therefore, although the cross correlation coefficient is known to be a good variable in identifying and separating chaff echoes from precipitation echoes, it is suggested that additional care should be taken when using the cross correlation coefficient solely in removing chaff echoes.


chaff echo;dual polarization radar;polarimetric parameters;X-band;precipitation echo


  1. Anderson, A.D. and Hoehne, W.E., 1956, Experiments using window to measure high altitude winds. Bulletin of American Meteorology Society, 37, 454-457.
  2. Balakrishnan, N. and Zrnic, D.S., 1990, Use of polarization to characterize precipitation and discriminate large hail. Journal of Atmospheric Sciences, 47, 1525-1540.<1525:UOPTCP>2.0.CO;2
  3. Brandt, M.B. and Atkin, D.V., 1998, Chaff in the vicinity of thunderstorms in Southern California on 6 June 1997. NWS Western Region Technical Attachments, 98, Available online at (November 5th 2012).
  4. Doviak, R.J. and Zrnic, D.S., 1993, Doppler radar and weather observations. Academic Press, New York, USA, 562 p.
  5. Garbacz, R.J., Cable, V., Wickliff, R., Caldecott, R., Buk, J., Lam, D., Demarest, K., and Yee, A., 1975, Advanced radar reflector studies. The Ohio State University Electro Science Laboratory, Department of Electrical Engineering; prepared under Contract F33615-72-C-1435 for Aeronautical Systems Division, Wright-Patterson Air Force Base, Ohio (AFAL-TR-75-219).
  6. Gorgucci, E.D., Scarchilli, G., and Chandrasekar, V., 1999, A procedure to calibrate multiparameter weather radar data using the properties of the rain medium. IEEE Transactions on Geoscience and Remote Sensing, 37, 269-276.
  7. Han, H.-Y., Heo, B.-H., Kim, W.G., You, C.-H., Gu, J.-Y., and Lee, J.-H., 2010, Chaff echo identification and removal algorithm. Proceeding of the Autumn meeting of KMS 2010, p. 262-263. (in Korean)
  8. Han, H.-Y., Heo, B.-H., Jung, S.-H., Lee, G.W., You, C.-H., and Lee, J.-H., 2011, Elimination of chaff echoes in reflectivity composite from an operational weather radar network using infrared satellite data. Atmosphere, 21, 285-301. (in Korean)
  9. Illingworth, A.J. and Caylor, I.J., 1989, Cross polar observations of the bright band. Preprints, 24th Conference on Radar Meteorology, Tallahassee, American Meteorological Society, 323-327.
  10. Jessup, E.A., 1972, Interpretations of chaff trajectories near a severe thunderstorm. Monthly Weather Review, 100, 653-661.<0653:IOCTNA>2.3.CO;2
  11. Jung, S.-H., Lee, G.W., Kim, H.-W., and Kuk, B.J., 2011, Development of convective cell identification and tracking algorithm using 3-dimensional radar reflectivity fields. Atmosphere, 21, 243-256. (in Korean)
  12. Kim, D.S., Lee, D.I., Kim, P.K., and Rinehart, R.E., 2006, An experiment of chaff diffusion in clear sky using a WSR-88D radar. Journal of Korean Meteorological Society, 42, 225-236.
  13. Lee, D.I., 2000, A WSR-88D radar observation of chaff transport and diffusion in clear sky. Bulletin of Korean Environmental Sciences Society, 4, 263-271.
  14. Maddox, R.A., Howard, K.W., and Dempsey, C.L., 1997, Intense convective storms with little or no lightning over central Arizona: A case of inadvertent weather modification? Journal of Applied Meteorology, 36, 302-314.<0302:ICSWLO>2.0.CO;2
  15. Martner, B., Marwitz, J.D., and Kropfli, R.A., 1992, Radar observations of transport and diffusion in clouds and precipitation using TRACIR. Journal of Atmospheric and Oceanic Technology, 9, 226-241.<0226:ROOTAD>2.0.CO;2
  16. Nam, K.-Y., Jang, K.H., Choi, Y.J., and Ryu, S.B., 2010, Analysis of chaff echoes using dual polarimetric radar. Proceedings of the Autumn meeting of KMS 2010, p. 416-417. (in Korean)
  17. National Institute of Meteorological Research (NIMR), 2010, Research for the meteorological observation technology and its application (II). 308 p. (in Korean)
  18. Rinehart, R.E., 2010, Radar for meteorologists. Rinehart Publications, Nevada Missouri, USA, 482 p.
  19. Vasiloff, S. and Struthwolf, M., 1997, Chaff mixed with radar weather echoes. NWS Western Region Technical Attachment, 97-02, 10 p.
  20. Vasiloff, S., 2002, Chaff and the WSR-88D precipitation processing system. NWS Western Region Technical Attachment, 02-09, Available online at (November 11th 2012).
  21. Warner, J. and Bowen, E.G., 1953, A new method of studying the fine structure of air movements in the free atmosphere. Tellus, 5, 36-41.
  22. Ziegler, C.L., Rasmussen, E.N., Shepherd, T.R., Watson, A.I., and Straka, J.M., 2001, Evolution of low-level rotation in the 29 May 1994 Newcastle-Graham, Texas, storm complex during VORTEX. Monthly Weather Review, 129, 1339-1368.<1339:TEOLLR>2.0.CO;2
  23. Zrnic, D.S. and Ryzhkov, A.V., 1999, Polarimetry for weather surveillance radar. Bulletin of American Meteorology Society, 80, 389-406.<0389:PFWSR>2.0.CO;2
  24. Zrnic, D.S. and Ryzhkov, A.V., 2004, Polarimetric properties of chaff. Journal of Atmospheric and Oceanic Technology, 21, 1017-1024.<1017:PPOC>2.0.CO;2


Grant : 관측지진 기술지원 및 활용 연구

Supported by : 국립기상연구소