Dear Dr. Chen and co-authors,

After reading the revised submission, some issues need to be cleared. Please refer to the list of comments below.

I think the structure of the Introduction should be improved. Paragraphs with info on the biological processes should be following each other and the same holds for those treating physical processes.

Please write units with negative exponents throughout the manuscript, e.g. m s-1

Language use is sloppy. In many cases, part of which I indicate below, the sentences are not logical and carry syntax errors. Please go through the the text.

P3, L5 1953 (not 1985)
P3, L7-8 “ Seasonal cycles of phytoplankton concentrations signify the annual growth activity in pelagic systems” Is this a correct sentence? In particular the word “signify” seems strange here.

P3, L9 “The most common cycle is the spring bloom …” This is incorrect. A spring bloom cannot be a cycle. Please change wording.

P3, L11 Often a secondary peak in production develops … (add “in production” because the reader wouldn’t know what kind of peak is meant.

P3, L39 insert “during” after Sv
P4, L14, 19 m s-1 (format with negative exponent)

P4, L16-17 “Local sea breezes, superimposed on synoptic southerly winds (with speeds often >15 m/s), are prevalent in austral summer and spring (Pattiaratchi et al., 1997).” Delete this sentence. Exactly this info was given in lines 13-14

P4, L17-18 Change to: Storm systems in winter are associated … (As it is in the manuscript, it is again repeating the info above)

P4, L19 delete “storm”
P4, L20-21 Storms cannot have winds. Please change, for example: In the study region a typical pattern in winter is strong north/north-easterly winds blowing for 12 to 52 hours,

P4, L22-23 Dito: “Summer storms have southerly winds over a period of 3-4 days …” Storms cannot have winds. Change to: Summer storms are southerly over a period of 3-4- days …

P4, L24-25 This is a strange sentence. Above it was written that winds are high in winter, and here that there are calm conditions. Please change, for example: Calm conditions (<5 m s-1) are observed between winter storm fronts during autumn and winter (March-August).

P5, L34-36 “Understanding … shelf.” This is repeated info from lines 30-32
P6, L20-21 delete “Teledyne Webb Research Slocum Electric” (repeated info from above)

P6, L38 Please define QA/QC
P7, L4 please use “°C” not °Celsius

P7, L11 “errors” instead of “faults”?
P7, L14 delete “after”

P7, L24 delete “ensure ongoing reliability”
P8, L13-14 “Summer storms, which usually lasted 36 hours, caused strong, southerly winds (> 25 m/s)” Storms cannot cause winds. Please change wording.

P8, L33 “at lower depths” It is not clear to me which depths are meant here. Do you mean greater depths further offshore? Please make clear.

P8, L36 delete “layer”
P9, L3 delete “depth”

P9, L32 I think “monthly mean water masses” is not the correct expression. What you mean is Monthly mean temperature and salinity (which describe water masses)

P9, L33 delete “year round,” If there are 4 from 12 exceptions, year round is not appropriate.

P9, L35 “indicated” instead of “showed”?
P9, L36 “were warmer” than what?

P9, §3.3 Please indicate for what regions and their boundaries and depth ranges the monthly means were calculated.

P10, L5 Please refer to Fig. 5
P10, L12 and further. In Figs 6, 7 and 8 the anomalies are shown against the seasonal average. The sections in the 4 seasons do not have the same spatial extent. How does that influence the seasonal average and its anomalies?

P10, L19-20 “During spring, the temperature anomaly indicated that water to be vertically well mixed on the continental shelf (Figure 6a) with warmer water offshore” I think this conclusion is not allowed from this figure. The figure only says that the anomaly is not big on the shelf. Theoretically it is possible to have a stratified water column on the shelf, which is present during all seasons, and then the anomaly would also be small. Whether the water column is well mixed should be concluded from single sections. Second, are you writing here that the water on the continental shelf be mixed with warmer water offshore? The sentence is not unambiguous.

P11, L7 “This SCM was associated with the temperature and salinity distribution” This is not clear. Please write how it was associated

P11, L16 concentration
P11, L19-20 delete “The data highlights the interannual variability.” (repeated info)

P12, L22-23 “The water column was vertically stratified because of the presence of a DSWC on the upper shelf and a thermocline in the offshore waters …” This sentence says the water column was stratified because of a thermocline. This is circular reasoning. Please modify.

P12, L27-28 The winds were initially southerly and then changed to westerly and continued to be that way to 23 April … (add “continued to be that way”, because I think this is what you mean; if you do not add that, you just say that the winds continued to 23 April)

P12, L28-30 “On the upper shelf, the DSWC was eroded such that by 25 April, the temperature and salinity were vertically mixed in the water column (Figures 12e, k).” Which temperature and salinity? You cannot mix temperature and salinity, only water can be mixed.

P12, L30-31 “the salinity on the upper shelf was vertically stratified” Only the water column can be stratified.

P14 I think the first paragraph of the Discussion can be shortened significantly without losing information.

P14, L5 (relatively high costs, and …
P14, L6 seasonal

P14, L8 insert “layers” after sub-surface
P14, L11 Please avoid using “In this paper” again

P14, L15 insert “also” after have
P14, L31 “the river discharge is mainly deflected south in winter” Is there a reference for this contention?

P14, L38 “whilst the salinity increased” From which value are time it increased?
P14, L40 “due to heat loss to the atmosphere” instead of “due to atmospheric heat loss”?

P15, L35 … seasonality like in other regions …
P16, L4 “Thus” instead of “This”

P16, L5 insert comma after “this” for enhancing readability
P16, L15 “highlighted” not “lighted”

P17, L6-7 “Local and basin-scale ocean forcing affected the coastal hydrography (temperature and salinity) and biological variables (chlorophyll).” This is repeated info and can be deleted at this place.

P17, L16-24 Info in this paragraph appears verbatim in the Introduction. Please modify and shorten and avoid duplication.

P17-18, L34-2 This paragraph contains much info, about biological aspects, that is not relevant for the manuscript. Please delete or shorten strongly.

P18, L4-5 delete ”was used to study the seasonal and interannual variability across the Rottnest continental shelf and”. The sentence as it is in the text is awkward.

P18, L7 delete “(DSWC)” (this has been defined before)
P18, L8 delete “(ENSO)” (this has been defined before)

P18 The Conclusions section is mainly a summary. It is clear that some summing up will likely be needed in the Conclusions section, but I think here it is too much. The sentence towards the end of the section “It is concluded that the observed seasonal and interannual variability in chlorophyll concentrations were related to the changes in physical forcing.” Is the first concluding remark. However, it is trivial. Please restructure the whole section, so that both summary and real conclusions are in balance.

Table 1 °C, not °Celsius
Figure 2 I am not sure everything in the wind roses will be readable. Please could you increase the fonts?

References
Below there are some examples of incomplete references. Please go through the reference list for other possible errors.

Feng, 2003 should be:
Feng, M., G. Meyers, A. Pearce, and S. Wijffels (2003), Annual and interannual variations of the Leeuwin Current at 32°S, J. Geophys. Res., 108, 3355, doi:10.1029/2002JC001763, C11.

Field et al pages 237-240
Kilpatrick et al: Journal of Geophysical Research: Oceans, 123, 7550–7563. https://doi.org/10.1029/2018JC014248

Pattiaratchi, C. and Buchan, S: Reference is incomplete

Thank you and best wishes
Mario Hoppema