**5. Summary**

The AltiKa shows an excellent retracked SLA data coverage over the coastal water, with ≥85% data availability for most locations of the experimental regions (three out of five regions). AltiKa measurements also can get as close as ~1 km from the coastline. This is extremely better than the performance of previous missions (i.e., Jason-2 and Envisat), which can generally provide measurements beyond ~7–10 km from the coastline.

For overall results, it shows that the Ice-1 is the optimum retracker over the Southeast Asia coastal region, with the percentage of data availability up to 90% and the minimum distance as close as 0.9 km from the coastline. Nevertheless, the amount of data that can be recovered through the retracking algorithm depends on the coastal topography and sea states, in which different coastal characteristics have different impacts on the altimetric signals. Thus, this makes the performance of each retracker differ between different locations.
