Review of "Is the Atlantic Ocean driving the recent variability in South Asian dust? " by Banerjee et al.

General comment: the paper presents new results on large scale processes that control the interannual variability of the dust concentration above the South Asia. The authors used satellite measurements from 2001 to 2018 to analyse the frequency of days (over a month, called DA_%) when the dust optical depth above South Asia is high. Using NCEP/NCAR reanalysis, they found that an increase in DA_% was associated to an increase in SST in the mid-latitude North Atlantic, and a cooling in the Subtropical North Atlantic between 2011 and 2018. The authors presented a detailed analysis, based on NCEP reanalysis and CEMS simulations, of anomalies in the wind fields and SST to explain the link between the SST variability in the Atlantic Ocean and the dust emission over South Asia. The correlation was linked to large scale transport pattern anomalies and a weakening of the South Asia monsoon.

The paper is well written and the results are of interest for the community. I will accept this paper for publication after addressing the following comments:

Specific comment:

1) Section 3.3 is a bit long and probably needs some reorganisation. Figures 6 and 7 discuss the capabilities of CESM to simulate dust and precipitation in South Asia, and not so much the mechanisms that link dust activity to North Atlantic SST. I'm wondering if figure 6 and 7 should go in section 2.2 instead, and leave figures 8 and 9 in section 3.3. That way you will only discuss anomalies in section 3.3, which will help to follow the arguments of section 3.2 .

2) introduction: you don't mention the impact of the indian ocean dipole (IOD) and its impact on the monsoon and potentially on the dust emission. Please add references and comments.

Technical comments:

figure 5 top: the coast lines need to be enhanced.

abstract: you should rephrase lines 22-23 to better explain what you mean by 10% (20%) and 30% (50%).

Review Comments

On “Is the Atlantic Ocean driving the recent variability in South Asian dust?” by Priyanka Banerjee, Sreedharan Krishnakumari Satheesh, Krishnaswamy Krishna Moorthy.

Recommendation: major revision

General comments: The study of the impact of dust on the South Asian region Asian monsoon is important to the environmental improvement. The study conducted by Banerjee et al. indicated the impact of the interannual variability of dust aerosls over the South Asia has been experienced shift from Pacific Ocean SSTs to the North Atlantic SSTs in recent years. The authors further found that the NAO is the crucial factor to impact the North Atlantic tripole pattern, then leading to associated atmospheric large circulation change, therefore affecting the dust over the South Asia. However, the logical of the mechanisms is not clear, lots of parts confused me, so, I recommend it be accepted for publication after major revisions.

Specific comments:

1. Write all the EL Niño/La Niña words correctly in this article, such as Line 38, 42, 53, etc.
2. Line 118-119, “The SD is low indicating that high dust activities persist over these regions.” In the Fig1a, this SD of this region is the biggest than other regions, the value is between 4-8.
3. Line 178, the reference of the data “monthly SST and sea ice from Hadley Centre (1870-1981)” is missed.
4. Line 179-181. About the “NAtl” simulation, I don’t know the specific region of the North Atlantic Ocean, is the south two areas of the North Atlantic tripole SST?
5. Line 197-198, why you divided two periods from 2010, what is the basis?
6. Line 203, shifted north-eastwards, is that corrected? Not the westward?
7. Line 223, the partial correlation method, you not mentioned in the methods, please introduce it.
8. Since the NADI index from April to June is well correlated with the dust index, and the NADI index from April to June is also analyzed in the article, why is the annual SST field given here?
9. Line 241-234. The signal of the Pacific SST is weak, only is a small region shown the 90% confidence level, how does it affect the dust? What is the physical process? Instead, the signals are stronger in the north Pacific and tropical Atlantic Ocean, did you analyze the process?
10. Line 254-256. NAO is the seesaw pattern of the relationship between the Icelandic Low and the Azores High, which is the atmospheric circulation pattern, not the SST pattern. The Icelandic Low is located over the north of 60 degrees, and your two signifant regions are both over the south of 50 degrees, which is not the NAO, but two south branches of the North Atlantic tripole.
11. Line 301-303, What is the linkage with the NAO and the North Atlantic tripole? With all the wind fields, SST, pressure fields and precipitation fields introduced above, it is completely impossible to see the process how the Atlantic SST influences NADI?
12. Line 311-313, the North Atlantic tripole pattern is also significant in Figure 5b. The relationship between NADI and the North Atlantic tripole SST in the early period is very significant, and the relationship between NADI and the North Atlantic tripole SST in the late period is only significant in the two southern regions. It cannot be seen that the influence from the Pacific Ocean in the early period is changed to the influence from the Atlantic Ocean in the late period.
13. Line 316-318, in figure 5b, the south branch SST over the tropical Atlantic is also present the negative pattern, which is resembled as the 5f. It is consistent with the SST distribution in the late tropical Atlantic Ocean. Why the atmospheric pressure not perform the uniform anomalous high?
14. Line 318-321, the relation with the North Atlantic SST leads to the convergence and precipitation, but how the North Atlantic SST result in? I am confused the process.
15. Line 321-324, why the convergence over the Mediterranean region can induce the next area divergent?
16. In figure 5, Why not directly correlate the dust index with each air and sea field and see how climate variables modulate the dust index? In addition, both the correlation between Atlantic NADI index and the Atlantic tripole SST field in the early and late periods is significant. How can we see the physical process of dust index changing from influenced by the Pacific Ocean to the Atlantic Ocean? You don’t give the Pacific SST’s relation pattern in the early periods.