New dynamic atmospheric (DAC_ERA) and dry tropospheric (DT_ERA) correction have been computed for the altimeter period using the ERA-Interim meteorological reanalysis. The corrections improve sea level estimations in Southern Ocean and in shallow waters; the impact is the most important for the first decade of altimetry, when operational meteorological models had a weaker quality. DT_ERA remains better in the recent period. New corrections significantly impact long-term regional trends.

Sea level is a key indicator of climate change and has been monitored by satellite altimetry for more than 2 decades. The evaluation of the performances of the altimeter missions can be performed by comparison with in situ-independent measurements from Argo profiling floats. This allows for the detection of altimeter drift and the estimation of the impact of a new altimeter standard. This study aims at characterizing the errors of the method thanks to sensitivity analyses to different parameters.

This paper presents various respective data improvements achieved within the European Space Agency (ESA) Climate Change Initiative (ESA CCI) project on sea level during its first phase (2010-2013), using multi-mission satellite altimetry data over the 1993-2010 time span.