Dear Karen and co-authors,

Many thanks for your responses to the reviewer comments and for submitting a revised manuscript. I also thank the reviewers for their positive and constructive feedback. Having read the reviewer comments, your responses to them, and the revisions that you’ve made to the manuscript, I feel that you have addressed the majority of the comments. However, there are a number of specific points, listed below, where I felt your response to the reviewers could have been more complete. Before accepting your manuscript for publication in Geosci. Model Dev., I kindly ask you to address these specific points.

Once completed, I will then be happy to recommend your manuscript for publication.

Regards,
Fiona O’Connor

Specific comments:
1. You’ve added some text to indicate that other GCMs are using cubed-grid coordinate systems. May I please ask you, however, to provide the full name for GFDL AM3?

2. Referee #1 asked about whether the bulk convective scheme used in GEOS-Chem is also used in other CTMs that use RAS. Although other CTMs like TOMCAT use a convective scheme based on archived mass fluxes, I am not aware that TOMCAT uses RAS. May I please ask you to be more specific in your answer to this query?

3. Referee #2 commented that it would be interesting to include a discussion on the horizontal and temporal differences for those plotted as zonal means in Figure 6 – although I accept that you cannot address temporal differences due to length of model simulations, I feel that you can address the point in relation to differences in the horizontal. Could I please ask you to include such a discussion?