A realistic computer simulation of reverberation from a moving sea surface has been used to compare time and ensemble averages. The experiment simulated has a directional source and an omnidirectional receiving hydrophone located at a depth of 350 yd (320 m). The surface is insonified in a strip of constant width independent of range. The reverberation is calculated in three “windows” of width 0.1 sec located at 0.5, 1.0, and 1.5 sec for a fully developed sea resulting from wind velocities of 10 and 20 kt (5.1 and 10.3 m/sec). The pulse waveform is two cycles of a 1‐kHz sinusoid. The sea surface is generated by using random phases in a Fourier polynomial of 100 terms. It is shown that, when the reverberation is reduced in the manner suggested by Ol'shevskii, the derived process is not stationary, but behaves like a narrow‐band noise of constant amplitude and random phase. The lack of stationarity arises because the statistical properties of the phase change with time. The backscattering strengths of the sea surface, computed for six combinations of grazing angle and sea state, agree only moderately well with experimental measurements at sea.