Probabilities and statistics for backscatter estimates obtained by a scatterometer with applications to new scatterometer design data
Abstract
The values of the Normalized Radar Backscattering Cross Section (NRCS), sigma (o), obtained by a scatterometer are random variables whose variance is a known function of the expected value. The probability density function can be obtained from the normal distribution. Models for the expected value obtain it as a function of the properties of the waves on the ocean and the winds that generated the waves. Point estimates of the expected value were found from various statistics given the parameters that define the probability density function for each value. Random intervals were derived with a preassigned probability of containing that value. A statistical test to determine whether or not successive values of sigma (o) are truly independent was derived. The maximum likelihood estimates for wind speed and direction were found, given a model for backscatter as a function of the properties of the waves on the ocean. These estimates are biased as a result of the terms in the equation that involve natural logarithms, and calculations of the point estimates of the maximum likelihood values are used to show that the contributions of the logarithmic terms are negligible and that the terms can be omitted.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 April 1989
 Bibcode:
 1989STIN...8922779P
 Keywords:

 Backscattering;
 Probability Density Functions;
 Radar Cross Sections;
 Radar Scattering;
 Water Waves;
 Wind Velocity Measurement;
 Air Water Interactions;
 Maximum Likelihood Estimates;
 Monte Carlo Method;
 Remote Sensing;
 Scatterometers;
 Statistical Tests;
 Wind Direction;
 Communications and Radar