Dear Stephen et al.,

Thanks very much for the revised manuscript and detailed responses. I am happy with your revisions, but do wish to see that the manuscript includes a bit more discussions on the implications of these model runs.

Specifically, you summarize findings in the abstract, but I feel there is a lack of ending/conclusions. After all, what is the implication of these findings in terms of scientific understanding, model improvement, and observational needs for the future?

The manuscript is partly motivated by the fact that few studies focus on the Arabian Peninsula, compared to the Sahara and East Asia (as mentioned in your Introduction). How are your findings different from what we knew about the other regions? Providing some thoughts/discussions (or compare/contrast) on it in one paragraph will greatly enhance the significance of the manuscript.

Additionally, you may wish to reword a bit about Line 31, Page 3, since I don't think you have really addressed the impact on costal mesoscale features in this manuscript.

Finally, please state which collection of MODIS AOD was used in the study. If it is collection 6, Rob Levy's paper may be more appropriate than Remer et al. (2005).

Please feel free to let me know if you have any question. I look forward to receiving your revisions soon.

Cheers
Christine