1998 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

IEEE Transactions on Antennas and Propagation
Volume 46 Number 1, January 1998

Table of Contents for this issue

Complete paper in PDF format

Scattering from Breaking Gravity Waves Without Wind

P. H. Y. Lee, J. D. Barter, K. L. Beach, B. M. Lake, H. Rungaldier, H. R. Thompson, Jr., and R. Yee

Page 14.

Abstract:

Scattering experiments from breaking gravity waves conducted at a wave tank facility at small grazing angles in the absence of wind are analyzed. Breaking gravity waves are studied using a fully plane polarimetric horizontal (HH), vertical (VV), vertically transmitted and horizontally received polarization (VH), and horizontally transmitted and vertically received polarization (HV) pulse-chirped X-band radar in conjunction with optical instruments: the plane polarimetric optical specular event detector (OSED) and side-looking camera (SLC). Spatially and temporally resolved radar backscatter has been measured and temporally correlated to the data obtained from the optical diagnostics. The experiments yield the following results: 1) enhanced scattering compared to Bragg scattering levels occurs throughout the evolutionary process of wave-breaking, i.e., the radar scatters strongly from both the unbroken and broken surfaces; 2) an explanation is found for the observation that the scatterer Doppler frequency is slightly less than the Doppler frequency corresponding to the fundamental wave phase speed; 3) a representative non-Bragg cross section of a breaking wave can be obtained; and 4) a breaking wave surface is found to be an efficient depolarizer.

References

  1. P. H. Y. Lee, J. D. Barter, K. L. Beach, C. L. Hindman, B. M. Lake, H. Rungaldier, J. C. Shelton, A. B. Williams, R. Yee, and H. C. Yuen, "X-band microwave scattering from ocean waves," J. Geophys. Res., vol. 100, pp. 2591-2611, 1995.
  2. P. H. Y. Lee, J. D. Barter, K. L. Beach, E. Caponi, C. L. Hindman, B. M. Lake, H. Rungaldier, and J. C. Shelton, "Power spectral lineshapes of microwave radiation backscattered from sea surfaces at small grazing angles," Proc. Inst. Elect. Eng.-RSN, vol. 142, pp. 252-258, 1995.
  3. P. H. Y. Lee, J. D. Barter, E. Caponi, M. Caponi, C. L. Hindman, B. M. Lake, and H. Rungaldier, "Wind-speed dependence of small-grazing-angle microwave backscatter from sea surfaces," IEEE Trans. Antennas Propagat., vol. 44, pp. 333-340, Mar. 1996.
  4. J. D. Barter and P. H. Y. Lee, "Optical polarimetric imaging of scattering surfaces," Appl. Opt., vol. 35, pp. 6015-6027, 1996.
  5. P. H. Y. Lee, J. D. Barter, K. L. Beach, B. M. Lake, H. Rungaldier, J. C. Shelton, H. R. Thompson, Jr., and R. Yee, "Dependence of polarimetric Doppler spectra on breaking-wave energy," in Proc. Int. Geosci. Remote Sensing Symp., Lincoln, NE, May 1996, vol. IV, pp. 2201-2203.
  6. --, "Depolarization in microwave scatterometry," in Proc. Int. Geosci. Remote Sensing Symp., Lincoln, NE, May 1996, vol. IV, pp. 2213-2215.
  7. P. H. Y. Lee, J. D. Barter, and H. R. Thompson, Jr., "TRW experiments at OEL-UC Santa Barbara--Part 6: Lineshape analysis of breaking-wave spectra," Redondo Beach, CA, TRW Rep. 63817-6001-UT-11.1, Jan. 1996.
  8. P. H. Y. Lee, J. D. Barter, K. L. Beach, C. L. Hindman, B. M. Lake, H. Rungaldier, H. R. Thompson, Jr., and R. Yee, "Experiments on Bragg and non-Bragg scattering using single-frequency and chirped radars," Radio Sci., vol. 32, pp. 1725-1744, 1997.
  9. P. H. Y. Lee and J. D. Barter, "Profiles of breaking gravity waves," Redondo Beach, CA, TRW Rep. 63817-6001-UT-13.1, Aug. 1996.
  10. H. C. Yuen and B. M. Lake, "Nonlinear dynamics of deep-water gravity waves," in Advances in Applied Mechanics.New York: Academic, 1982, vol. 22, pp. 68-225.
  11. P. H. Y. Lee, J. D. Barter, K. L. Beach, B. M. Lake, H. Rungaldier, H. R. Thompson, Jr., and R. Yee, "Scattering from breaking waves without wind," Redondo Beach, CA, TRW Rep. 63817-6001-UT-15.4, Mar. 1997.
  12. M. V. Berry, "Interpreting the anholonomy of coiled light," Nature, vol. 326, pp. 277-278, 1987.
  13. M. S. Longuet-Higgins, "On the overturning of gravity waves," in Proc. Royal Soc., London, U.K., 1981, vol. A-376, pp. 377-400.
  14. J. C. Lin and D. Rockwell, "Instantaneous structure of a breaking wave," Phys. Fluids, vol. 6, pp. 2877-2879, 1994.
  15. G. T. Ruck, D. E. Barrick, W. D. Stuart, and C. K. Krichbaum, Radar Cross Section Handbook.New York: Plenum, 1970, vol. 1.
  16. --, Radar Cross Section Handbook.New York: Plenum, 1970, vol. 2.
  17. B. Werle, SMS Inc., Woodland Hills, CA, private communication, 1997.
  18. S. Frasier, "Recent sea spike and ocean surface current measurements obtained with the focused phased array imaging radar (FOPAIR)," presented at Radar Scattering Ocean Surfaces Meet., Santa Barbara, CA, Aug. 1997.
  19. M. A. Sletten, D. B. Trizna, and J. P. Hansen, "Ultrawide-band radar observations of multipath propagation over the sea surface," IEEE Trans. Antennas Propagat., vol. 44, pp. 646-651, May 1996.
  20. --, "Current and future directions in field measurements of high-resolution radar scattering," presented at Radar Scattering Ocean Surfaces Meet., Santa Barbara, CA, Aug. 1997.