This manuscript reports on a numerical modelling study that examines the impact of the size distribution of iron-bearing anthropogenic emissions on the transport and deposition of soluble iron to the oceans. The paper is extremely well written and the work is presented clearly and concisely. I have no hesitation in recommending that it is suitable for publication in ACP with only minor revisions.

Specific Comments

Line 1. The work reported focusses exclusively on the size distribution at emission of anthropogenic iron. The title of the paper does not reflect this. I suggest that “Representation of iron aerosol size distributions of anthropogenic emissions is critical in evaluating atmospheric soluble iron input to the ocean” would give a better representation of the subject of the paper.

L 84. Given the dominance of dust as a source of Fe, it might be helpful for the reader to be given a little more detail on the representation (and validation) of the size distribution of dust Fe in the model. Similarly, the model described identifies various Fe-bearing minerals in anthropogenic emissions (L 100 – 101). Presumably at least some of these minerals also occur in dust. How does the model treat these minerals in dust, and how are the anthropogenic and dust fractions handled in the comparison to the aircraft observations (e.g. Fig. 3)?

L 96-97. Please comment on the implications of the assumption of internal mixing of Fe with all other aerosol components for your results.

L 189 – 190. Please explain this statement further.

L 223 – 224. Perhaps some clarification is needed here? The differences referred to do appear to be more pronounced over much of the global ocean, but not over the Southern Ocean.

L 225 – 227. Is the solubility enhancement referred to here relevant to dust Fe, anthropogenic Fe, or Fe in general?

Technical Corrections

L 102. Delete “taken into account”.

L 117. Also add “ of anthropogenic emissions” to this section heading?

L 139. “A similar…”

L 190. “… used as an …”

L 250. “iron source”, rather than “iron emission”?

Fig. 8. Please add a description of the two panels. (b) shows a percentage difference. What is this difference relative to?

This study shows the effects of varying the iron emission size distribution on global-scale simulations to diagnose iron concentration in the atmosphere and ocean deposition. Four different size distributions are studied, properly justified, and their results are compared to aircraft observations, allowing them to conclude on the closest simulated distributions. The methods lack some details about the iron emission and deposition processes. Finally, some comments on the possible biases of using a global model could be useful, reflecting on the possibility of higher resolution models being helpful in further elucidating this phenomenon. Therefore, I recommend a minor revision. Some minor comments follow:

In the abstract, it would be great to highlight which findings are new.

L55 are all of these papers working with global models? Is there a variety of local to global approaches and if so, how does grid resolution and microphysics models differ?

L118 Is it also possible that iron emissions have a different size distribution in other parts of the world? How could this simplification be considered for future work?

L95 I don't completely follow how the emissions are prescribed or calculated. Is it homogeneous over all surfaces in the world? Same with its absorption. Do they change over time? 

Fig. 4,5,6: Are these plots derived from yearly averaged values?