Spectral parameter estimation of CAT radar echoes in the presence of fading clutter

Abstract

The 430 MHz, 2 MW radar at the Arecibo Observatory is currently being used as a stratospheric‐troposheric (ST) radar. One of the problems in the automatic analysis of the signals come from the very large amplitude of the ground clutter echoes. The problem is agravated by the fading of these signals, which makes it difficult to discriminate them from the desired stratospheric returns. A parameter estimation technique that parameterizes the first three‐spectral moments corresponding to the desired stratospheric signals as well as a few Taylor series coefficients of the auto‐correlation function of the clutter is presented. The three first moments can be obtained in this manner even in the presence of clutter 50 dB stronger. The technique automatically takes care of instrumental and processing biases. Spectrum aliasing presents no problem. A sequence of fine altitude and high temporal resolution wind profiles is presented, showing the potential of the instrumental and technique for the study of stratospheric dynamics.