|The authors have done an excellent job to address my concerns on the original submission of this paper. The revision is much improved both in terms of content and organization. I recommend publication subject to a few minor adjustments as described below. I do not need to see the final revised version of the paper.|
General: Since the paper is so long, it might be helpful to include a table of contents at the front end with the various sections and subsections listed. That way the reader can orient with a big picture overview and, if they are interested in only a subset of topics, can navigate directly to the relevant sections.
Line 65. "topography". Do you mean "geography"?
Line 298. Kessler et al, 1995 and McPhaden 1999 proposed this connection before Bergman, so they should be cited as well.
Line 362-64. The juxtaposition of semi-annual with intraseasonal variability here is a little abrupt. Maybe move the reference to semi-annual variability to the section on the Wyrtki jets or provide a smoother connection at this point.
Section 3.2.2. Please point out that time scales for the MISO as for the MJO. The MJO is classically characterized by 30-60 day periods but MISOs can also occur on 10-20 day time scales (Goswami et al, 2016) and there are studies that have identified a 3-7 day time scale MISOs (e.g. Roman-Stork et al, 2020).
Section 22.214.171.124. A new paper has appeared online by Zang et al (2021) on the Somali Current/Undercurrent that might be good to cite in this section.
Lines 2081-82. There has been progress on understanding circulation at intermediate and deeper depths, at least in the equatorial band. Huang et al (2018) summarize Indian Ocean studies of deep ocean propagating features and present some new results. You could possibly fold a short discussion of this topic into section 4.3.3 if you felt is would be of benefit. But it's not necessary given how much territory you've covered already in the paper.
Line 2113-14: It might be helpful to mention marine heatwaves and their ecosystem impacts here.
A final suggestion (though I'm guessing the authors have already considering this)--some kind of acknowledgement or maybe even a dedication to the recently deceased co-author Satya Prakash.
Goswami, B.N., S.A. Rao, D. Sengupta, and S. Chakravorty. 2016. Monsoons to mixing in the Bay of Bengal: Multiscale air-sea interactions and monsoon predictability. Oceanography 29(2):18–27, http://dx.doi.org/10.5670/oceanog.2016.35.
Huang, K., McPhaden, M. J., Wang, D., Wang, W., Xie, Q., Chen, J., et al. (2018). Vertical propagation of middepth zonal currents associated with surface wind forcing in the equatorial Indian Ocean. Journal of Geophysical Research: Oceans, 123, 7290–7307. https://doi.org/ 10.1029/2018JC013977
Kessler, W.S., M.J. McPhaden, and K.M. Weickmann, 1995: Forcing of intraseasonal Kelvin Waves in the equatorial Pacific. J. Geophys. Res., 100, 10,613–10,631.
McPhaden, M.J., 1999: Genesis and evolution of the 1997-98 El Niño. Science, 283, 950-954.
Roman‐Stork, H. L., Subrahmanyam, B., & Trott, C. B. (2020). Monitoring
intraseasonal oscillations in the Indian Ocean using satellite observations. Journal of Geophysical Research: Oceans, 125, e2019JC015891. https://doi.org/10.1029/2019JC015891
Zang, N., Sprintall, J., Ienny, R., Wang, F., Seasonality of the Somali Current/Undercurrent System, Deep-Sea Research Part II, https://doi.org/10.1016/j.dsr2.2021.104953.