Dear Duncan and co-authors,

Many thanks for uploading a revised version of your manuscript. Having read all the reviewer comments and your responses to them, I note the following:

1. In relation to Reviewer #1, I feel that you have adequately addressed the main comments. In the case of Appendix A, a table is more suitable than adding definitions as footnotes in the main manuscript and I support your retention of Table 5 in Appendix A. However, I felt that you misinterpreted this Reviewer's comments in relation to Obs4MIPs. Firstly, Obs4MIPs is not the sole source of aggregated observational data and Reviewer #1 suggested that you include its name as an example rather than just referring to Teixeira et al. It is only a minor point but could I please ask that you change the statement "Aggregated observational data is often available from the obs4MIPS project (Teixeira et al., 2014)". to "Aggregated observational data is often available (e.g. from the Obs4MIPs project, Teixeira et al., 2014)".

2. In relation to Reviewer #2, there were a number of comments made by this Reviewer which did not appear to have been addressed. The first was in relation to the explanation of Formula 1. Although you indicated that it had been re-worded, I saw no evidence of that. Are you sure that you uploaded the most recent revised manuscript? Secondly, this reviewer also requested that some indication of the error messages that CIS would give in the case where a would-be user was trying to do something not allowed e.g. Note that model data can't yet be plotted (Section 5). Could you please add such messages concisely in order to address the Reviewer's comments but without making the manuscript too unwieldly? Finally, the Reviewer requested that you add a discussion about mismatching the sample and data array dimensions. I note that you've added a new figure to explain this but could you add a couple of lines in response to this comment? Otherwise, you addressed all other comments sufficiently.

The only other comments that I had were minor as follows:

3. Update Eyring et al. 2016a and 2016b references
4. Give full name for PMP (Pg 2, line 18)
5. Correct spelling (Therefore -> Therefore) on pg 13, line 12.
6. Caption of (newly added) Figure 4: Change "an gridded sampling" to "a gridded sample"

Could I please ask you to respond to these comments and once completed (and uploaded), I will recommend that your manuscript be accepted for publication in GMD.

Thanks again,
Fiona O'Connor