Christian Schwatke (DGFI-TUM, Germany)

The combination of different altimetry missions is mandatory in order to conduct long-term sea surface analysis with high temporal and spatial resolution. Without a rigorous inter-mission calibration the seamless connection between time series of different missions is hardly possible. Moreover, the calibration reveals problems of single missions and helps to improve the data quality of instruments and correction models.

DGFI-TUM routinely executes a multi-mission crossover analysis (MMXO) based on all altimetry missions available since 1992 (including also missions rarely used, such as GFO, ICESat or HY-2A). The method provides time series of radial errors for each mission included in the investigation with respect to one reference mission (TOPEX). The estimated radial errors allows for correcting each altimeter measurement and to derive one consistent long-term altimeter data set with high spatial and temporal resolution. By analyzing the calibration results, detailed information on the quality and deficiencies of the different altimeter missions and on the inter-mission consistency are revealed. In addition to relative range errors, stochastic properties of the time series as well as geographically correlated errors can be computed and analyzed.

This presentation will focus on the validation of the new mission Jason-3: range bias, instrument drifts, as well as geographically correlated errors will be analyzed. Moreover, the reprocessed Jason-1 GDR-E data set will be examined and its improved consistency to Jason-2 will be shown. In addition, first results for Sentinel-3 might be presented given sufficient data availability.