Backscatter variability observed in C-band and Ku-band scatterometer data

The backscatter from ocean waves measured by scatterometers is primarily determined by the speed and direction of near-surface wind, while other influences (temperature, salinity, swell, etc.) appear to be secondary effects. A complete theoretical geophysical model, incorporating all influences on the backscatter, appears beyond the current state of science; empirical estimates of the wind-backscatter relationship do not incorporate non-wind influences and suffer from variability due to unmodelled parameters. Having previously developed a method of estimating this variability directly from scatterometer measurements, this paper provides an analysis of ERS-1 (C-band) and NSCAT (Ku-band) data to identify some governing factors in the value of the modeling variability.