Hi Wolfgang,

Thank you for submitting your revised paper.
I really enjoyed the original submission which provided a helpful analysis of ALK evaluation metrics and made good use of your new preformed ALK tracer.
The reviewers added some thoughtful suggestions for improvements and hence a clearer paper with greater potential uptake by the community.

I must therefore admit to being a little disappointed, despite a thorough reply to the reviewers, that you made so few and so minor changes to the manuscript.
Unfortunately, I don't think you have quite yet adequately address these in the manuscript itself.
Please go back to the reviews and your replies, and see where your manuscript could be further clarified and usefully incorporate some of the discussion arising (e.g. as in your replies).

For instance:

(1) While I agree with your reply that the ALK-DIC metric was not intended as an ALK evaluation metric and hence contrary to John Dunne's suggestion, given the apparent common use of ALK-DIC and potential confusion in the context of your manuscript, you do need to include e.g. a short paragraph of discussion regarding it (even if you do not calculate it and carry out any in-depth intercomparison) and cite the relevant literature.

(2) You need to bring out a little more from the CMIP5 model tests -- I agree with points #3 and #4 of John Dunne. Method evaluation is not entirely separable from model evaluation, particularly here as you include multi model results in 2 different places. In diagnosing why models differ in a particular method, you additionally elucidate and test the method itself. I hence do not see this as 'diluting' your focus or intention.

(3) Regarding the main 'Comment' of Referee 2: could you not include some of this discussion and calculations in improving the manuscript? You call it an 'interesting suggestion' yet nothing appears in the revision. If both you and the Referee find it interesting, could you not share this with all readers?

(4) Please see where else clarifications and/or additions, perhaps based directly on some of your replies, might be incorporated in order to create an improved manuscript with maximum clarity.

This should not take you too long nor overly hold final publication up, as you have already clearly thought about the reviewers comments and provided a reasonably comprehensive response to many of them.
I look forward to seeing final product.


andy

Thanks for the final adjustments.
I am happy to see this go to press.
I look forward to seeing the subsequent papers, putting it to the (CMIP5) test.