Sea Level Rise from space:30 years of Calibration/Validation to ensure the continuity of satellite altimetry measurement

Calibration and validation of altimetry missions is essential to ensure the continuity and stability of long-term data records (e.g. sea level data record). Over a 30-year time series, it is imperative to guarantee the consistency between various altimetry missions, despite their differing measurement techniques (including both the altimeter and the radiometer), calibration modes and processing algorithms.

Here we provide an in-depth analysis of the evolution of on ground instruments for calibration/validation, of processing chains and methods used to assess and monitor altimetry performances since TOPEX-Poseidon (1992). We begin by examining ocean cross-calibration techniques used to harmonize mission time series, with a focus on geophysical retrievals and long-term stability. We then highlight the algorithm improvements that have been made over the past three decades, which have enhanced the reliability and accuracy of geophysical parameters (e.g., sea level, significant wave heights, wind speed). Finally, we provide an overview of current and future calibration techniques that are of crucial importance for altimetry calibration.