M. Joana Fernandes (University of Porto, Faculty of Sciences, Portugal); Gommenginger Christine (National Oceanography Centre, Natural Environment Research Council, United Kingdom); Scharroo Remko (European Organisation for the Exploitation of Meteorological Satellites, Germany)

This work presents the new achievements obtained at the University of Porto in designing a SSB modeling approach globally applied for all reference missions. The proposed technique, first tested for the Jason-1 mission, proves to have good performances for a wide range of ocean conditions when compared with the established SSB corrections currently in use.
In addition to Significant Wave Height (SWH) and Wind Speed (U10), which are the common physical parameters retrieved directly from the altimetric signal and used as model predictors for SSB corrections, the inclusion of a third predictor acting as a mediator parameter designed by the Mean Wave Period (Tz) derived from radar altimetry, has proven to improve the model performance in explaining some of the SSB variability. The proposed methodology relies on nonparametric modulation and statistical techniques, with simplicity and extensibility in mind, flexible enough to be implemented in the TOPEX and Jason-2 missions. The suggested approach is also computationally efficient, capable of generating a stable model with a small training dataset, a useful feature for the recently launched altimetric missions, as is the case of the new Jason-3 mission. This study presents the extension of this model to TOPEX, Jason-2 and Jason-3. In addition, the model was also run for the recently Jason-1 GDR-E data set, providing a consistent set of SSB corrections for the four reference missions. Model performance is assessed by comparison with existing SSB corrections for each mission, inter-comparisons during the period of the tandem missions and by sea level anomaly variance analysis.