Removal of Covariant Errors from Altimetric Wave Height Data

The echo waveforms received by conventional radar altimeters are interpreted by retracking algorithms to give estimates of range, wave height, and backscatter strength. However, in response to fading noise on the waveform leading edge, common retrackers, such as MLE-3 and MLE-4, show correlated errors in wave height and range. This correlation is used to develop a correction to the wave height data that reduces the high-frequency variability by ∼22%, without affecting the global distribution of values. This correction also results in a closer matchup of Jason-2 and Jason-3 data during their tandem phase. Although the correction is quite straightforward in practice, the appropriate conversion factor has to be determined for each combination of altimeter and retracker. There are also remaining open questions concerning the needed low-pass filtering