The probability distribution of NSCAT measurements

Due to the on-board signal processing used by NSCAT, the Gaussian distribution model for the power measurements used in the wind retrieval algorithm is only an approximation to the actual distribution. Working from first principles and the design of the NSCAT signal processor the authors derive the distribution of the NSCAT measurements as a function of the normalized radar cross section, NRCS, the signal to noise ratio and the cell number. The resulting distribution is skewed relative to the traditional Gaussian model. Simple compass simulations are used to compare the accuracy of winds estimated using the actual and Gaussian model distributions. These results are readily generalizable to other scatterometers and applications involving spectral estimation from averaging modified periodograms