Dear Dr. Zhang,

the public discussion of your manuscript has provided us with two
referee comments, and one additional short comment. After having read
your replies, I feel that you have addressed the comments in an
adequate way. Thank you.


There was some disagreement in the general appraisal of your
manuscript in the referees' reports: Anonymous Referee #1 was overall
positive about the manuscript and recommended publication after minor
revision only, whereas Anonymous Referee #2 was more critical and
asked for major revisions, although (s)he did not want to review the
revised paper again.

I therefore decided to give the revised paper a more in-depth review
by myself. I find that the criticisms of Anonymous Referee #1 have been
addressed quite comprehensively in the revised manuscript, except for
a few isolated points.
This is, unfortunately not the case regarding some important points
raised by Anonymous Referee #2, that are well discussed in the
online replies, but that must then also be discussed in the manuscript.

Please find below a list of points that I would like to ask you to
address in the next revised manuscript, that I invite you to sumit.
Some of them are minor points, but clarifying those right now will
make readers' lives easier, as one will not have to go through the
whole discussion to gather some important information that is missing
in the paper or that remains unclear. I further add a few technical
issues to address. Page numbers refer to the most recently uploaded
manuscript version, except where explicitly stated otherwise. Please
address all of the points mentioned below.


I am ready to accept your revised manuscript for *publication subject
to minor revisions (Editor review)* and I am looking forward to read
your revised manuscript.

Best regards,

Guy Munhoven




Main questions and comments
---------------------------

1. Do the fossil fuel CO2 emission data have some time resolution?
The current manuscript seems to say NO (p. 7, ll. 12-13: "There
is no time structure in the fossil fuel emissions."), although
I then do not see any need to cycle them repeatedly (p. 7, ll. 10-11).
The FFDAS web site (http://hpcg.purdue.edu/FFDAS), on the other hand,
indicates that their data are on a "0.1° x 0.1°, hourly grid."
Please clarify this, specify if and how the FFCO2 data have been
post-processed before use in the model (especially regarding the time
dimension), the more since there is later a comparison with station
data at hourly resolution (section 3.3). The text really must be
unambiguous regarding this point.


2. Anonymous Referee #2 asked about potential regridding issues related
to possibly different spatial resolutions of MERRA and PCTM.
While this is clarified in the online Author's Comment, that information
(and a short statement why this is important) is still missing in the
revised manuscript. Please amend.


3. Anonymous Referee #1 pointed out that the Dutch city of Groningen
is not a coastal city (p. 9, l. 21). I agree with this observation
as Groningen is indeed located somewhat inland and I find that the
reply given regarding this point is not clear.


4. The description of the characteristics of the TAP site is not entirely
clear. It would first of all benefit from some streamlining: it is
stated right at the beginning that TAP is in close proximity to a heavily
populated coastal area (p. 11, l. 3); later on the same page, the
location information is partly repeated, and completed. Why not give
all of the relevant information right away (situation, names of nearby
urban areas. The text indicates that the station is situated
300m offshore in the Tae-ahn Peninsula. I find this contradicting:
either it is offshore, or it is in the Peninsula (i.e., on land).
The information that I have been able to find rather indicates that
it is on land (the site is of the type "vegetated peninsula") which
would suggest to me that it is a land station. Please check this and
correct if necessary. It would furthermore be helpful to state that
TAP is located int the Republic of Korea.


5. The points raised by Anonymous Referee #2 in the two last
paragraphs of her/his review (p. C1121 therein) are well addressed
in the online Author's Comment. The points raised by Anonymous
Referee #2 are, however, very important and also need to be
discussed in the manuscript. Please complete the discussion in
the manuscript on the basis of your reply.



Technical details:
-----------------

The Supplement currently only includes a single figure. Are there any
compelling reasons for not including that figure directly into the main
manuscript? Not mandatory, but, if wa can simplify readers' lives...


Throughout the paper: the correct SI abbreviation of kilogram is "kg",
with a small "k" (not "Kg")


Page 3, line 19: Reference Peylin et al. (2013) is still incorrect
or missing.


Page 6, lines 13-14: Reference Gurney and Coltin (2014) is missing


Page 7, line 21: please add "(longitude x latitude)" after "1.25˚ x 1.0˚"
at the end of the line.


Page 12, line 2: "largest value by about" should probably read
"largest value of about"


Page 12, lines 7-9: "High-frequency signals are also shown
through the year in the hourly timeseries for the TAP site, indicating
the impact of synoptic-scale atmospheric transport."
This sentence looks strange to me. Should it not better read
"The hourly timeseries for the TAP site also contains high-frequency
components throughout the year, indicating the impact of synoptic-scale
atmospheric transport." or "... also shows high-frequency behavior
throughout ..."


Page 20, Figure 2: the scale annotations are barely readable


Page 22, Figure 4: the annotations are barely readable. Please enlarge.
I suggest to arrange the panels vertically instead of horizontally.


Page 23: the blue stars indicating the location of TAP are not well
visible, especially on the left-hand panel. I suggest to draw it
in white. The annotations of the scales are barely readable; please
enlarge.

Dear Dr. Zhang,

thank you for uploading the revised manuscript. I have now checked the
corrections made, and they appear to respond to all the referees' and
my own comments.
I am pleased to inform you that I accept your paper for
publication in GMD subject to a few technical corrections detailed
below.


Thank you once again for considering Geoscientific Model Development
for the publication of your research worK.


Best regards,

Guy Munhoven




Technical details:
-----------------
(line numbers refer to the manuscript w/o tracked changes)


p. 6, lines 16-21: I suggest to rewrite as follows (please check
and amend if necessary):
"FFDAS version 2.0 originally estimates fossil fuel CO2 emissions
at 0.1˚ annual resolution over the globe. From this product, we
have derived a fossil fuel CO2 emission distribution suitable for
use with our model by dividing the annual amounts in each grid cell
by 2920 to obtain emissions that are evenly distributed in time,
at the temporal resolution of our model (i.e., three hours)."


p. 6, end of the page: formatting problem. The title of section 2.2
is within the previous text paragraph.


p. 12, lines 9--15 should be rewritten. There is confusion
between grid and grid-cells and the text is difficult to read.
I suggest the following (please check and amend if necessary):

"TAP is a coastal station (36˚43′N, 126˚07′E) located in the Tae-ahn
Peninsula (Republic of Korea). This site is in close proximity to
the cities of Seosan and Taean. TAP is assigned to an ocean
grid cell on the PCTM grid. The emissions on this grid-cell are
aggregated to adjacent land grid-cells after regridding.
The site is thus located in the negative portion of the emission
dipole (emission difference: -24.1 TgC/gridcell/yr)..."


p. 26, in the legend: "Blue stars" should read "White stars" now