Estimation of the Sea State Bias Using the Interpolation Method and Applications to Inter-Mission Calibration

An alternative approach to empirical, non-parametric sea state bias (SSB) modeling for satellite altimeter measurements was developed with the intention of providing a simple, transparent, and efficient means to derive both a raw and smoothed SSB solution. This alternative approach, referred to as the interpolation method, maintains the flexibility to generate 2-D or 3-D models using either direct or difference measurements of the sea level anomaly uncorrected for SSB (uSLA). The final, smoothed SSB solution derived using the interpolation method is obtained over three steps, with a supplemental fourth step that consists of estimating a model-dependent dual-frequency ionosphere calibration bias to correct for a relative range + SSB error. A tandem phase analysis for all Topex/Poseidon, Jason 1-3 and Sentinel-6 Michael Freilich satellite altimeter inter-calibration periods reveals that the ionosphere calibration bias removes an ionosphere-related component from intermission bias calculations required to generate the long-term sea level record.