1. A method of investigating a region of interest with a radar, the method comprising: propagating a radar signal to the region of interest; generating a waveform with a uniform pulsing scheme or nonuniform pulsing scheme; collecting sampled time-domain radar data scattered within the region of interest; calculating a sample covariance matrix with the sampled time-domain data; and calculating parameters of models that describe ground clutter, system noise, and weather signal, and that minimize a likelihood function calculated with the sample covariance matrix.