Dear authors

As you might see the decision procedure of BG has changed in order that the associated editor is better guiding the authors through the revision process.

I consider the required and mostly already discussed changements as major revisions, please follow what I alraedy sugegsted in my comment and the suggestions by reviewer 3. Reviewer 4 was more critical and asked for mechanistical explanantion. I am aware that you presenetd a statistical approach. It is important to clearly state this aim.

Best wishes
Albrecht Neftel, Co-editor-in-chief, BG

Dear authors

As you might see the decision procedure of BG has changed in order that the associated editor is better guiding the authors through the revision process.

I consider the required and mostly already discussed changements as major revisions, please follow what I alraedy sugegsted in my comment and the suggestions by reviewer 3. Reviewer 4 was more critical and asked for mechanistical explanantion. I am aware that you presenetd a statistical approach. It is important to clearly state this aim.

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Please take the following third review into account:

The authors should use (and define) NOy deposition and NHx deposition and not use the terms NOx deposition and NH3 deposition.
NOy deposition should defined as the sum of dry and wet deposition of NOx (NO + NO2) and reaction products (HNO3 and NO3 aerosol). NHx should be defined as dry and wet deposition of NH3 and reaction product (NH4 aerosol).
The procedure for calculating the depositions should be given into more detail. What is the scale of the deposition used, is it 50x50 km2 and if so how are outputs from a model on a 150x150 km2 scale “translated” depositions on a 50x50km2 scale? Is it e.g. assumed that the relative distribution between 50x50 km2 grid elements within a 150x150 km2 does not change with time? This is especially important to mention when one goes further back in time, as the geographical distribution of emission sources is likely to change over time, e.g. due to different techniques used, different geographical distribution of animals, differences in land use etc. Which emissions are used to calculate the historical depositions and which assumptions are made to calculate them? (e.g. the same techniques as used now?).

***

Best wishes
Albrecht Neftel, Co-editor-in-chief, BG

Dear authors

I do accept the paper for publication in BG. Please read carefulyl the proof reads after tne copy editing step to avoid misunderstandings.

With kind regards
Albrecht Neftel, co-editor-in-chief, BG