CoAuthors

Anny Cazenave (CNES-LEGOS, France); Olivier Henry (CNRS-LEGOS, France); Pierre Prandi (CLS, France); Benoit Meyssignac (CNES-LEGOS, France)

High-precision satellite altimeters help in measuring the variations in sea level since the early 1990s. After a number of such successful altimetry missions like Topex/Poseidon, Jason-1, Jason-2, Envisat etc., SARAL-AltiKa, a high resolution altimetry mission based on the Ka frequency band that can also cover high latitudinal zones was launched in February 2013. Even though the data available from this very recent mission is still not utilizable for climate research owing to its short duration, in this study we have performed a validation of SARAL-AltiKa sea level product. To start with, in the first part of validation, the comparison of SARAL-AltiKa sea level data in terms of spatial pattern is performed. The temporal mean spatial pattern of SARAL-AltiKa sea level between March 2013 and February 2014 is compared with the Jason-2 sea level pattern over the same time period. The steric sea level temporal mean spatial pattern is then subtracted from the altimetry sea level temporal mean pattern over March 2013-January 2014 and this residual pattern is then compared with GRACE ocean mass signal. In the second part of validation, global mean sea level (GMSL) evolution from SARAL-AltiKa is compared with the GMSL of AVISO product and Jason-2. Next, the mean sea level evolution is studied on the three oceans: Pacific, Indian and Atlantic. As a last part of validation, the SARAL-AltiKa sea level temporal curve is compared with several tide gauge records based on the interpolation of the sea level data around 1° radius of the tide gauge site. All these various comparisons and validations prove the high performance of this new altimetry mission.