As the tide gauge measurements define the absolute reference
in the determination of the altimeter bias, a meticulous
check is crucial and as many outliers as possible must
be eliminated from the in situ time series. This has been
done by using cross-comparisons between the various tide
gauge instruments available at the two Corsican sites,
and by analysing carefully the coherency of the time series
in order to identify drifts, gaps or jumps in the datasets.