The authors have done a thoughtful and complete job of addressing the reviewers' comments. As a result, the paper is significantly easier to follow for the non-specialist and the potential application of the results to field studies is more readily apparent. I encourage the authors to acknowledge the efforts of the 2 reviewers in improving the manuscript in their Acknowledgements.

The manuscript is now ready for copy editing and publication. A few minor editorial corrections are noted below.
P3, L7: I think the last word of this sentence is missing. It should be something like "... advection-diffusion regime."
P4, L3: "temporary" should be "temporarily"
P8, L19: "equilibrate to each other."
P10, L11: "the probability that a tracer is entrained and moves forward, ..."

Dear Authors,
Thank you for the changes you have made to your ESurf manuscript. I am delighted to inform you that your paper has now been accepted for final publication. The AE has noticed a few minor corrections - which I hope you can address in the proofing stage.
All the best and thank you for publishing with us.
Tom Coulthard