At the crossover point between the interleaved tracks
085 and 222, where a double estimation was done, the
results are less coherent, with differences around 2 cm in
the mean biases. This is mainly due to the fact that the
altimeter SSH are not measured at the same time for the
two tracks. Indeed there is a 5-day delay between the measurements
on the two tracks and they consequently do not
“see” the same oceanic conditions. Moreover, there may be
systematic differences between the two tracks, as one is
ascending (track 085) and the other is descending (track
222). Finally, the paths used to bring the SSH from the
crossover point to the coast are different for these two estimates,
which may introduce different errors in the estimate,
due to the mean profiles. The two estimations should in
fact be seen like two different crossover points.