Ground clutter from irregular surfaces was measured using an L-band long range air-route surveillance radar (ARSR) at very low grazing angles, between 0.13 and 0.25. It is shown that the ground clutter amplitude statistics themselves do not always follow a Weibull distribution, but rather the residual amplitude after the double canceller moving target indicator (MTI) obeys a Weibull distribution. Therefore, the unsuppressed residual ground clutter will be suppressed by means of Weibull CFAR processors.

Ground clutter from cultivated land was measured using an L-band long range air-route surveillance radar (ARSR) at very low grazing angles, between 0.21 and 0.32. It is shown that the Weibull-distributed ground clutter obeys a Weibull distribution in the frequency domain after processing by the discrete Fourier transform (DFT). Thus the new Weibull-CFAR should be considered to suppress such clutter in the frequency domain.