IMPACT OF SCALE SEPARATION IN THE COHERENT TWO-SCALE MODEL ON DOPPLER AND NORMALIZED CROSS SECTION PREDICTIONS FOR SEA BACKSCATTER - A NUMERICAL STUDY

The study investigates the accuracy of the Doppler and normalized radar cross section (NRCS) predictions when using the coherent scattered field expressions of the Two-Scale Model (TSM). This is done through large-scale Monte Carlo simulations in the 2D space, followed by comparisons to the results of integral equation-based exact numerical calculations. Of particular interest is the choice of the scale separation parameter (intrinsic to the TSM) that minimizes the error for either the Doppler spectrum moments or the NRCS. The optimal separation length is found to be much smaller (about 1-1.5 electromagnetic wavelengths) than the conventionally accepted values. This quantity is seen decreasing with stronger wind.