Title :
An Empirical Study of Breaking Wave Contribution to Radar Backscatter from the Ocean Surface at Low Grazing Angle
Author :
Hwang, Paul A. ; Sletten, Mark A. ; Toporkov, Jakov V.
Author_Institution :
Remote Sensing Div., Naval Res. Lab., Washington, DC
Abstract :
The anomaly of radar sea spikes, defined here as the non-Bragg scattering events with backscattering cross section of horizontal polarization exceeding that of vertical polarization, has been associated with steep wave features possibly going through wave breaking process. This property is employed for remote detection of breaking waves. The results are used to quantify the effect of wave breaking on radar returns. Large increase due to breaking is found in the Doppler velocities of both polarizations (about 50% faster with breaking). The effect of breaking on the backscattering cross section is much stronger for the horizontal polarization (with 15 to 20 dB enhancement) and relatively small in the vertical polarization (on the order of 0.5 dB fluctuations). The presence of swell reduces the impact of breaking waves on radar return in comparison to the scattering from wind seas.
Keywords :
marine radar; ocean waves; radar cross-sections; wind; Doppler velocities; horizontal polarization; low grazing angle; nonBragg scattering events; ocean surface; radar backscattering cross section; radar returns; radar sea spikes anomaly; steep wave features; vertical polarization; wave breaking process; wind seas; Backscatter; Doppler radar; Fluctuations; Oceans; Polarization; Radar cross section; Radar detection; Radar scattering; Sea surface; Surface waves; Breaking waves; Radar cross section; Sea spikes;
Conference_Titel :
Geoscience and Remote Sensing Symposium, 2008. IGARSS 2008. IEEE International
Conference_Location :
Boston, MA
Print_ISBN :
978-1-4244-2807-6
Electronic_ISBN :
978-1-4244-2808-3
DOI :
10.1109/IGARSS.2008.4780040
