Sea-spike backscatter from a steepening wave

H-pol and V-pol backscatter cross sections at incidence angles of 85 degrees, 60 degrees, and 40 degrees are computed at X-band for two temporal sequences of simulated sea waves, one with a wavelength of 1 m and the other with a 2.3-m wavelength, that are steepening as they undergo breaking. At an incidence angle of 85 degrees (5 degrees grazing) H-pol and V-pol backscatter from these waves are shown to have the characteristics of a sea spike. At a 60 degrees incidence angle only the 1-m sequence produces a sea spike, No sea spike is seen from either sequence at 40 degrees.