Dear Dr Ponsoni.
Thank you for ypur submission tc-2019-257 to TC.

"Statistical predictability of the Arctic sea ice volume anomaly:
identifying predictors and optimal sampling locations"

Pls review the comments of both reviewers carefully and address these
together with the ones outlined here in your revised version.

Editor's general comments:

* End of Abstract:
Add info on how much of the SIV var anomaly is achieved by six well-placed data
locations.

* 1-24: Add what is impacted: "to bring significant impacts" --> To what?
Then connect to the follow-on effects (your "Regionally, native").
--> You might need to bring your "global" impacts forward and then discuss
the "regional" ones, as the former are related to the climate system, the
others are follow

* 2-10: "meltdown" is very strong and inappropriate wording. Suggest to change,
i.e., "intense sea-ice loss" or "rapid sea-ice loss".

* 2-19: Swart et al., [2015] are really about the relevance of internal variability
in coupled climate (CMIP style) models. The statement "it has been already shown
that trends in the pan-Arctic sea ice extent can be masked by its long-term variability
(Swart et al., 2015)" is not correct. Pls rephrase.

* There are some resolved issues on the underperformance of OHT, especially in conjunction
with SST as predictant. Would you kindly expand in the "Discussion" section?

* The early part of your paper promises an analysis on how spatial model resolution
affects the SIV prdictablity, but the manuscript do not follow through on this.
Pls explore this and discuss in the "Discussion" section.

* Pls separate the "Discussion" section from "Conclusion" section.


Minor comments:
1-2: Change "6" and "3" to "six" and "three".
1-3: Change "2" to "two".
1-6: Italize "in situ". -- Throught manuscript.
1-10: Change "4" to "four".
1-11: Change "enough" to "sufficient".
1-14: Change "6" to "six".
1-14: Change "As per 6 well-placed locations" to read "Adding further to six well
place locations" and remove "by adding new sites".
1-15: Change "4" to "four".
... Pls change all numericals (in text), that are less than twelve to "words".
2-29: Remove "trivial".
2-31: Replace "for feeding" with "as input into".
3-11: Replace "broadly" with "well"
3-20ff: Remove "Following this introduction ... observing sampling design."
3-30: Assuming that the horizontal resolution (and subsequently bathymetry, inputs, etc
associated with the grid res) is the only difference, then:
a) Replace "model configurations" with "model horizontal grids", and
b) Remove "These configurations differ by their horizontal grid resolution (in both
the atmosphere and ocean)." (line 3-31).
4-3: Figure references in the body of a manuscript should not be a repeat of the figure
caption. Instead figures should be referenced in the text to support a statement/
description of the displayed parameter(s). --> Rephrase.
4-24: Remove "best".
4-25: Replaece "non–significant" with "insignificant".
6-1: Regarding reference to "Table 1", pls refer to my comment at 4-3.
6-Tab1: In caption remind the reader why there is no CorrCoef for OHT and SIV for
the high-res models.
7-Fig2: The order of the sub-figures is illogical, pls relabel.
8-19: Change "at least not" to "especially not"
8-30: Change "to feed the Eq. 4" to "in Eq. 4".
9-15: Change "we borrow the concept" to "we follow the concept".
9-25: Change "Figure 3 shows how would be the region of influence ... ensemble of datasets."
to "The region of influence for a station arbitrarily placed at the North Pole, as
defined by the ensemble of datasets, exhibits depatures from concentric reflecting
the transpolar drift. (Fig. 3)."
14-4: Change "6 models" to "sixe model realisations".
16-Fig7: Why does the colour scheme for each subfig in the right hand column change?
Please show for a single colour scheme.
22-29: Change "ALL" to "all".
23-2: Change "by observing platforms" to read "by autonomous observing platforms".
23-4: Change "The first" to "The former".
23-4: Change "not turn out to" to "did not act as".
23-4: Change "predictor (at least 5 not when using monthly means)." to "predictor,
at least not when using monthly means."
23-19: Change "that only 4 stations are enough to overpass" to "that as few as four
stations are sufficient to pass".
24-7: Change "might be in a free-ice region in the future." to "might in the future
be ice free."
24-11: Spell out "MOSAiC".

Regards, Petra

Dear authors.
Thank you for your submission on a refined image-processing algorithm and its application to Operation IceBridge (OIB) Digital Mapping System (DMS) optical images for the Arctic. This work presents a valuable improvement to the existing dataset, especially with view of harvesting crucial information on Arctic meltponds. I note, however, that such work needs to be conducted rigorously and complete. As outlined by both reviewers and the public comment, your original submission showed some shortcomings with regard to those. In the meantime your responses to the three submitted comments indicates that a fully revised manuscript is likely within scope for publication in TC. I invite you iterate on the comments the reviewers and public, together the points noted below, before submitting your revised manuscript (ms).

General comments:

* The original submission is rather qualitative and at times handwaving. To improve the ms, pls provide quantitative information: For example, what percentage of imagery is not processed due to being cloud affected (l112); or "what is a large number" (l118).

* Provide physical motivation for the choice of your tresholds: 15m (l148), 27.5m (l152).

* Be clearer in how you compute if underlying sea ice is First Year [FY} or Multi Year [MY] ice. I.e., what are your criteria to determine FY vs M Y (l214)?

* The discussion section needs to better reflect the results/findings from this work/these data and be strengthened overall. In its current form the ms leans towards a data-announcement paper (i.e., suitable for Earth System Science Data).

Specific comments:
l76: Your categorisation into freezing and melting occurrences of OIB's DMS imagery appears rather crude, especially considering the range of locations observed. Pls justify or refine this approach.

l143: Training datasets at https://github.com/wrightni/ossp:
These are shown to be from 2018 (V2): Are these the correct and up-to-date datasets relating to this
late 2019-submitted ms??

l176: Provide URL/link for the data processed for this ms at the NSIDC WWW pages.

l250: Correct "Lincoln sea" to "Lincoln Sea".

l268: There is a subsection "4.1" but no further subsection in 4: Remove by joining the 4.1 subsection title with the "4" section title.

Dear authors.
Thank you for the diligent technical revision, much appreciated.