Experimental investigation of radar backscatter from plunging breakers using an ultrawideband radar and visible/infrared cameras

Interim results of a laboratory investigation of the low-grazing angle radar backscatter generated by plunging breakers are presented. A primary objective of this investigation is to experimentally verify a scattering mechanism through which the horizontally-polarized backscatter generated by the breaker can exceed that at vertical polarization, without involving multipath propagation between the front face of the wave and its crest. The experiments were conducted at the University of Maryland-College Park wave tank, and involved the deployment of a dual-polarized, ultrawideband radar, multiple high-speed visible cameras, and an ultra-sensitive infrared camera. All instruments were deployed simultaneously on a moving carriage, located above the wave tank channel, that followed the breakers as they evolved in space and time. Representative ultrawideband radar data and optical images are presented in this paper.