Thank-you for your revised manuscript attending to all the review comments. Now I am just asking you to consider "Technical Corrections (see below) after which it should go directly into the publication procedure (i.e. no more intervention by me). There will be copy-editing and you should check that your intended meaning is retained. Thank-you for publishing in Ocean Science.
Yours sincerely
John Huthnance

Page 1
Line 4. “simulation” (delete final “s”)
Line 14. Better “. . 5-day forecasts, compared with a single . .”?
Line 16. Delete 2nd “to”
Line 18. Better “. . propagated down the water column . .”

Page 2
Line 6. Omit “,” after “(Bell et al., 2015)”
Lines 21-22. Better “. . resolution, to wavelengths as short as 20 km . .”?
Line 23. “involve” -> “make” ? (usually “make measurements” in English)
Line 30. “dynamic” -> “dynamical”?

Page 6 line 23. “background-error” ?

Page 7
Line 18. “. . were obtained by sampling . .”

Page 8 lines 2-3. “Better “. . data assimilation in . .” ?

Page 10
Lines 11-12. Better “. . with depth greater than 200 metres . .”
Line 12. From (2) I do not think that OSSE1 ER* is meaningful so cannot be compared with. End the sentence at “~ 35%.”?
Line 25. Better “significant ER* (~ 28 %) in the ocean forecast till the 5th day of forecast, . .”
Line 30. Better “This involve” -> “OSSE4 gave”?

Page 11
Line 15. Not “while is weaken”. Maybe “but the impact is weaker”
Line 21. Not “while is significant”. Maybe “. . small, but the difference between OSSE2 and OSSE4 (green line) is significant, showing the impact”
Line 26. “lowest” -> “least”
Line 28. Better “. . reduction of error (ERspec ~ 30 %). On the other hand . .” ?
Line 29. Better “. . to better resolve ocean dynamics . .” and add “,” after “variability”

Page 12
Line 7. “. . data significantly increased the coherence . .”
Line 31. I prefer “. . (OSSE1); large errors were observed . .”

Page 13
Lines 4, 6. Better to add “ER*” before the values “~28%” , “~35%”.
Line 7. Omit “,”
Line 17. “Cryosat2” ?
Line 24. “concerns”
Line 30. “constellation of . . . and one wide-swath mission (3N+1S) for the first day . .” (order)

Page 14
Line 16. “reduction of the error down to ~ 10% was observed”. This means the remaining error was only 10% of some reference value (which should be stated). But I think you might mean the reduction was 10%, i.e. “reduction of the error by ~ 10% was observed”.
Line 17. “with respect to” -> “compared with”
Line 19. “interferometer” (spelling)

Figure 2 caption
Line 2. “. . right: Swath-1+ Swath-2. Bottom . .” ?
Lines 2, 4, 5. Better “across-swath” (twice) and “along-swath”.

Figure 8 caption line 3. OSSE4 is at bottom but not “right”..

Table 2. The units “days”, “km”, “km” would be better alongside the respective headings “RC”, “FP”, “CTS”.

Table 3 caption line 3. Delete duplicate “the”.
Table 3. In row OSSE3 column T&S, should be “YES”?

Table 4 caption line 3. “. . in each experiment . .”