Dear authors,

you carefully addressed the major issues and now there are only few minor points left listed in the review from Wolfgang Dierking.

Best regards

Lars Kaleschke

Dear authors,

the manuscript has passed a rigorous review and was sufficiently improved to be accepted with some technical additions: 1) author contribution section, and 2) an additional supplement including the motion vectors used for validation.

However, I'd like repeat my concerns about the selection of datasets for validation: the selected TanDEM-X scenes depend on the availability of motion vectors from the coastal radar. Your method includes temporal filtering, optical flow and a feature tracking which does not always return results where in contrast a human observer could be able to derive reasonable motion vectors. To rely only on the automated motion products averaged over 1.5-3 hours dismisses many TanDEM-X scenes which could in principle be analysed with carefully hand-picked motion vectors from two consecutive images that have only a five minute difference. Such an analysis has been performed previously as stated in my first letter of December 3, 2018 in which I disclosed my potential conflict of interest. That said, I find your manuscript very worthwhile for future scientific discussion although I think that much more work could and should be done for a thorough validation.

Best regards,
Lars Kaleschke