Optimizing $\sigma ^{0}$ Information From the Jason-2 Altimeter

A radar altimeter´s normalized backscatter, sigma⁰, is used in many oceanographic applications to infer values of wind speed, wind stress, rain rate, and the presence of biogenic slicks. The waveform retracker used to estimate the key geophysical variables for the altimeters on the Jason-1 and Jason-2 satellites shows increased small-scale variability since the problem is ill-conditioned. A simple empirical adjustment to sigma⁰ improves the separability between various parameters and also improves the along-track profiles of sigma⁰. This leads to the following: 1) more realistic wind fields; 2) better discrimination of rain events; and 3) improved comparison between the Jason-1 and Jason-2 altimeters during their tandem mission.