|The new version of the paper has improved compared to the previous one. However, a couple of my earlier comments were not sufficiently addressed and are listed again below. Also, a number of new papers have been published that are relevant to this study (see below). The paper would benefit from referring to those as listed below.|
Introduction line 24: The authors agree that SAI is not a good abbreviation, but they don’t change it because it is wildly used. I do not agree that this is a good reason for using a misleading abbreviation. Again, the abbreviation should be changed to something like stratospheric aerosol geoengineering.
Page 2, Line 4: “stratospheric aerosol injection” is not correct if the authors are referring to Heckendorn, Niemeier, and English papers.
Line 13: A reference to Richter et al. (2017) would be relevant.
Line 21: Please add a reference to MacMartin et al. (2017), who show that is is more efficient to inject at multiple injection locations outside the equator that at the equator.
Page 7, Line 30: “so the exact ozone feedback is unclear” please remove that sentence and refer for example to Tilmes et al. (2009), who discussed in detail the changes of stratospheric ozone as the result of stratospheric aerosol geoengineering.
Page 9, Line 10ff: Here, you can also refer to Kravitz et al. (2017), who also looked at the same quantities.
Page 10, Line 18: Please also refer to Tilmes et al. (2017), who found very similar results for high vs. low injection cases.
Page 13, line 19ff, and page 15, line 20: A reference to Richter et al. (2017) would be relevant, as well as mentioning difference to the results found in their study.
Line 25: Please note, interactive chemistry has been shown to influence the response of geoengineering to the QBO (Richter et al., 2017).
Kravitz, B., MacMartin, D. G., Mills, M. J., Richter, J. H., Tilmes, S., Lamarque, J.-F.,…Vitt, F. (2017). First simulations of designing stratospheric sulfate aerosol geoengineering to meet multiple simultaneous climate objectives. Journal of Geophysical Research: Atmospheres, 122. https://doi.org/10.1002/2017JD026874
Tilmes S., Richter J. H., Mills M. J., Kravitz B., MacMartin D. G., Vitt F.,…Lamarque J.- F. (2017). Sensitivity of aerosol distribution and climate response to stratospheric SO2 injection locations. Journal of Geophysical Research: Atmospheres, 122. https://doi.org/10.1002/2017JD026888
MacMartin, D. G., Kravitz, B., Tilmes, S., Richter, J. H., Mills, M. J., Lamarque, J.-F., Tribbia, J. J., & Vitt, F. (2017). The climate response to stratospheric aerosol geoengineering can be tailored using multiple injection locations. Journal of Geophysical Research: Atmospheres, 122. https://doi.org/10.1002/2017JD026868
Richter, J. H., Tilmes, S., Mills, M. J., Tribbia, J., Kravitz, B., MacMartin, D. G.,…Jean-Francois, L. (2017). Stratospheric dynamical response and ozone feedbacks in the presence of SO2 injections. Journal of Geophysical Research: Atmospheres, 122. https://doi.org/10.1002/2017JD026912