Mean Sea Surface

Mean Sea Surface

The mean sea surface (MSS) provides the reference surface against which the sea level anomaly is defined. The mean sea surface used for S6MF is the MSS_CNES_CLS2022. This surface is obtained by combining all sea level height data from altimeters from 1993 - 2021. It is provided with an uncertainty estimate. The MSS is visually dominated by the geoid signal, a smaller component comes from the permanent part (long-term mean) of the dynamic ocean topography, showing the main ocean currents. 

As the MSS is used as a reference, its stability and the ability to assess measurements in comparison to it are more important than its absolute uncertainty. However, recent improvements in independent estimates of the geoid, may provide some benefits to separate the long-term mean of the dynamic ocean topography from the geoid signal.