|The authors have done a lot to address my concerns. I have the following suggestions:|
Eq. 6: I didn’t communicate this clearly in my last set of comments. When I said about accounting for 0<CF<1, what I meant was in Eq.6 you need some way of accounting for saturation in cloud fraction. When you calculate partial CF/ partial ln AI this doesn’t have any way of knowing if CF is already at 1 or 0. When adjustment forcing is calculated in Eq 6 you need some way of capping the forcing from being any more negative if CF=1 already or any more positive if CF=0, or if the projected change in CF would result in a value >1 or <0.
Conclusions: how does the interpretation of this study square with other studies looking at transient changes in aerosol that find near zero or decreased LWP with increasing Nd (Malavelle et al., 2017; Toll et al., 2019)?
Fig. 1 and 6-8: Please consider a zonal-mean plot along the side of each map plot for ease of interpretation. The colormaps are hard to read clearly. Why are some colorbars uneven (red saturates at 0.5 and blue at -3 in Fig 8, for example)? Please make colorbars symmetric about zero, or consider using something that is not diverging.
Fig. 3 Please title these plots.
Fig. 8: I still find it very odd that there is a substantial forcing from aci in the Southern Ocean. Previous studies have found almost zero PI-PD change in aerosol in this region (Hamilton et al., 2014). I acknowledge that this region might be more susceptible- and from looking at Fig. 1 ∆AI looks to be >0 so it seems that the calculation is internally consistent. However, comparison to Fig.8b of Myhre et al. (2013) shows that SPRINTARS is unique in having a nearly constant SO4 burden with latitude. The authors need to add at least one or two other aerocom models. Almost any model (HadGEM2, GISS, or ECHAM) would probably remove the band of strong ERFaci in the SH around 50S. This doesn’t really change the results of the study in the sense of the detection of a susceptibility, but is important to at least give a confidence interval on the forcing. The authors should also include a sidebar on Fig. 1a showing ∆AI as a function of latitude because it is difficult to differentiate small values in the map plot.
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Toll, V., Christensen, M., Quaas, J., and Bellouin, N.: Weak average liquid-cloud-water response to anthropogenic aerosols, Nature, 572, 51-55, 10.1038/s41586-019-1423-9, 2019.