Følgende kapitler er der foretaget små ændringer i. Se punkter for specifikke rettelser. Læs i øvrigt
kapitel Introduktion og 3.1 og se om der eventuelt er noget der kan skæres væk.:
Introduktion: Færdig rettet. Punkt (2-9)
Model setup. Færidg rettet. Se punkt 10-11
Ocean Flux: Færdigt. Punkt 12 -15 er ordnet. Rækkefølgen er ændret lidt. Derfor er der ingen
angivelser af linier. Læs det og se om I synes at det er godt nok.
Konklusion Punkt 16 medtaget
Punkt 17. Mangler. Er kort at medtage
Konk
Punkt 1 er der rettelser igennem hele artiklen (søg/erstat)
Dear Dr Rasmussen,
Both reviewers find that the revised version of your paper is improved and
should be published in Ocean Modelling, but reviewer 2 raises a number of minor
points that must be addressed. Reviewer 1 is satisfied but mentions in his/her
cover letter that he/she "found the introduction and subsection 3.1 a bit
long". I hope these are minor issues that can be taken care of rapidly in a
second revision.
Best regards,
Anne Marie Treguier
Reviewers' comments:
Reviewer #1: The authors have responded to my comments and have
modified/extended the manuscript where needed. I am satisfied with their
response.
Reviewer #2: ASSESSMENT
The manuscript has been much improved during revision. It now includes some
assessment of results in the context of limitations imposed by sparse
observations and imperfect parameterizations of real physical processes for
numerical simulation.
Unfortunately, there are a few issues remaining that need to be tweaked up.
These have to do with neglecting the impact of tidal flows on fluid drag
(seabed & ice canopy) in Nares Strait (see #11) and with model-to-observations
comparison of ocean structure (see #12, #13, #14, #15, #17).
Attention to these points may calm a lurking suspicion that the model may be
producing "good" results for wrong reasons.
My recommendation could probably be summarized as "Accept subject minor
revisions".
COMMENTS
1. The North Water: The authors state on page 4 that the name was coined by
whalers in the 18th century. However, this famous seasonal phenomenon is
variously called in the manuscript the "North Water Polynya", "NOW", the "NOW
polynya". I recommend that a single name should be used throughout, and
strongly recommend that the name used be that of longest lineage, namely the
North Water. I realize that new nomenclature was devised for the Canadian North
Water Project, but suggest that there was really no good argument to invent a
new name at that time.
Changed to the North Water.
2. Introduction: ". four main gateways from the Arctic Ocean". A fifth gateway,
frequently overlooked, is the Barents Sea Opening. See: Kwok, Maslowski & Laxon
2005. On large outflows of Arctic sea ice into the Barents Sea. Geophysical
Research Letters 32, L22503, doi:10.1029/2005GL024485.
Added the fifth in first line of introduction. Magnitude added to the last line of the
first paragraph. Line 21-24 and line 35-36
3. Introduction: ". a volume flux of 3.16 mSv into the Arctic Ocean". Ice
produced within the Canadian Archipelago is also exported eastward into Baffin
Bay. See: Agnew, Lambe & Long. 2008. Estimating sea ice area flux across the
Canadian Arctic Archipelago using enhanced AMSR-E. Journal Of Geophysical
Research 113, C10011, doi:10.1029/2007JC004582.
Added to introduction, 1st paragraph. Line 30-31
4. Introduction, para. 2: "Nares Strait & Baffin Bay . gradually become ice-free
in summer". True for Baffin Bay, but not for Nares Strait.
See:
http://ice-
glaces.ec.gc.ca/App/WsvPageDsp.cfm?Lang=eng&lnid=19&ScndLvl=no&ID=11676
linie 45-47. Correction made.
5. Introduction, para. 4: Kwok et al (2010). This reference is missing from the
reference list.
Corrected. Tjek
6. Introduction, para. 4, line 57: "and an ESTIMATED volume flux". It is
important to included "estimated" since the ice thickness was guessed, not
known.
Corrected. Line 62
7. Introduction, line 76: "this represents the cross-section .". Better to say,
"All estimates by Berit et al represent the cross-section that was measured; it
does not cover section B (fig. 1) from coast to coast or the zone above 35-m
depth".
Corrected line 81 – 83. Husk ret linie 79 30 m hvorimod der står 35 m til sidst I
paragraffen
8. Introduction, line 78: "Based on a short-term campaign in August 2003 .
salinity of 34.8". Suggest adding: "The estimates do not include the uppermost
26 m of the ocean, where current could not be measured by ship-based ADCP".
Corrected L 86-88
9. Introduction, line 141: "It is a relatively shallow strait with depths from
50-500 m". I think that this statement is not correct. The shallowest point on
the thalweg, is about 220 m depth, in Kane Basin. The deepest is in Hall basin,
about 750 m.
Corrected to sill depth variation from 215 m– 750 m. Line 149-151
10. Model Description, line 202: Melling et al (2008) indicate flux through
Jones Sound to be 0.3 Sv (Table 6), not 0.1-0.2 Sv as stated here.
Corrected
11. Model Description, line 243: Tides are ". regarded to be secondary effects".
I recommend that this statement should be substantiated by citation. A recent
paper by Dupont & Hanna at the Bedford Institute in Canada (bibliographic
reference unknown) might be relevant.
Added to last paragraph of model description. Ved ikke helt om det er korrekt. →
Nicolai er det her ok. Linie 253
Section 3.5 & fig. 10: The doubling of simulated ocean flux between 2006 &
2008 is startling. It would be very useful if the authors were to diagnose the
cause - wind, pressure gradient, baroclinic structure - and to present an
assessment as to whether it is attributable to natural cause or drift in the
model.
Added. An increase in difference of the sea surface height between the Baffin Bay and
the Lincoln sea accounts for most of the difference if not all. See line 490-497
13. Section 3.5, line 476-483: As I have mentioned earlier, each of the
empirical estimates of flux through Nares Strait has limitations - duration of
observations, fraction of the channel width measured, presence or absence of
data in the fast-moving surface layer. I think that it is important that the
reader be reminded of these limitations in this paragraph, which compares
simulations with data.
Added sentence in the end of the paragraph. See line 505-508
14. Section 3.5, para. 4 & fig. 11: This figure is disturbing from the viewpoint
of calculating freshwater flux. In the fastest moving part of the water column,
above 150 m depth, the difference between simulated and observed salinity is
1-1.5 ppt. Since fresh-water flux is referenced to a salinity near of 34.8,
that is, proportional to (34.8 - S), the impact of this difference of flux is
huge, 2.3/0.8 or almost a factor of 3 at 50-m depth (fig. 11). Admittedly, the
observations used by Kleim & Greenberg were quite limited - a few profiles from
1971 & 1985, but better information provided by Rabe et al are consistent with
earlier observations. What gives, to allow the model to do OK against
observations for fresh-water flux with this discrepancy in hydrographic
structure? The manuscript needs some informative interpretation here.
15. Section 3.5, line 491-493: I do not think neglect of melt-water from
Greenland would have much impact. Petermann contributes about 10 km3/y, whereas
this paper suggests that Nares Strait moves about 30 mSv, close to 1000 km3/y.
I suspect that the cause of the large discrepancy is something in the model,
hence my recommendation in (14) for a little detective work.
16. Conclusion, line 511-519: As I have mentioned earlier, each of the empirical
estimates of flux through Nares Strait has limitations - duration of
observations, fraction of the channel width measured, presence or absence of
data in the fast-moving surface layer. I think that it is important that the
reader be reminded of these limitations in this paragraph, which compares
simulations with data.
Correction added in the middle of the section.
17. Conclusion, lines 551-557: ". the modelled ice thickness that flows into
Nares Strait is on average 1.4 to 1.7 m . The corresponding ice thickness used
by Kwok is around 3 m". It would definitely be worth noting that the actual ice
thickness could be much higher, based on data published by Haas Hendricks and
Doble (Comparison of the sea ice thickness distribution in the Lincoln Sea and
adjacent Arctic Ocean in 2004 and 2005. Annals of Galciology 44, A121). It is
possible that Haas has data for the same years as covered in this modelling
study.