An inter-hemispheric seasonal comparison of polar amplification using radiative forcing of a quadrupling CO<sub>2</sub> experiment

Casagrande, Fernanda; Buss de Souza, Ronald; Nobre, Paulo; Lanfer Marquez, Andre

doi:https://doi.org/10.5194/angeo-38-1123-2020

Articles | Volume 38, issue 5

https://doi.org/10.5194/angeo-38-1123-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

7th Brazilian meeting on space geophysics and aeronomy

https://doi.org/10.5194/angeo-38-1123-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 38, issue 5

Regular paper

|

29 Oct 2020

Regular paper |

| 29 Oct 2020

An inter-hemispheric seasonal comparison of polar amplification using radiative forcing of a quadrupling CO₂ experiment

Fernanda Casagrande, Ronald Buss de Souza, Paulo Nobre, and Andre Lanfer Marquez

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Final revised paper (published on 29 Oct 2020)
Preprint (discussion started on 21 Aug 2019)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'major comments', Anonymous Referee #1, 09 Oct 2019
- AC2: 'Response to Anonymous Referee #1', Fernanda Casagrande, 10 Feb 2020
RC2: 'Review on Casagrande et al.', Anonymous Referee #2, 18 Oct 2019
- RC3: 'supporting pdf file', Anonymous Referee #2, 18 Oct 2019
  - AC7: 'Response to Anonymous Referee #2 => same', Fernanda Casagrande, 17 Feb 2020
- AC3: 'Response to Anonymous Referee #2', Fernanda Casagrande, 10 Feb 2020
- AC5: 'Response to Anonymous Referee #2', Fernanda Casagrande, 10 Feb 2020
RC4: 'Major comments', Anonymous Referee #3, 27 Oct 2019
- AC6: 'Response to Anonymous Referee #3', Fernanda Casagrande, 10 Feb 2020
AC1: 'Response to Anonymous Referee #1', Fernanda Casagrande, 10 Feb 2020
AC4: 'Response to Anonymous Referee #3', Fernanda Casagrande, 10 Feb 2020

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Publish subject to revisions (further review by editor and referees) (18 Feb 2020) by Igo Paulino

AR by Fernanda Casagrande on behalf of the Authors (02 Apr 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (02 Apr 2020) by Igo Paulino

RR by Anonymous Referee #1 (30 Apr 2020)

Suggestions for revision or reasons for rejection

L30 may->May
L31 BIAS->bias
L31 between->among
L41 had->has
L47 The authors should mention that the Antarctic sea ice has also been decreased in recent years (e.g., Schlosser et al., 2017; Turner et al., 2017; Konrad et al., 2018).
L43 intensify-> intensifies
L45 keys-> key
L63 Although the annual average temperature at northern mid- and high latitudes is increasing, the wintertime SAT has been decreased since 1990s, which may be due to Arctic sea ice loss (e.g., Honda et al., 2009; Cohen et al., 2012; Mori et al., 2014; Zhang et al., 2016). The authors should mention this point here.
L69 between->among
L78 CMIP5?
L79 between->among
L83 delete “simulations”
L88 describe-> described
L94 or->for
L98 operate ->operates
L99 delete “are”
L100 add a comma before ‘which’
L109 of -> in
L121 another paragraph and delete “a”
L123 amplified -> large
L147 CPTEC-INPE has-> CPTEC-INPE, has
L164 concentration -> concentrations
L169 It is confused. Please rephrase it.
L177 between -> among
L177 analyzes -> analysis
L180 near surface polar warming -> polar warming near the surface
L185 In all figure captions, you just need to use initial capitalization for the first word.
Figure 1: The title string should be ‘2008–2018 minus 1979–1989’.
L193 ‘Besides that, changes in atmospheric and ocean ciculation’???
L194 circulation -> circulations
L195 is also
L198 The upper or lower case form of ‘polar amplification’ should be unified.
L199 assesses-> assess
L200 involved we-> involved, we
L203 since->since it
L205 between->among
L207 Polar Regions-> polar regions (Please correct such expressions in the followings text)
L208 latitude-> latitudes
L212 showed-> as showed
L220 Flat->flat
L239 amplitude-> counterpart
L239 therefore does-> therefore it does
L242 decreases-> decrease
L245 separated-> separatedly
L249 between->among
L250 from->at
L259 delete “but”. … and decreases…
L261 between->among
L261 presented-> present
L267 between->among
L272 between->among
L285 near surface air temperature -> air temperature near the surface
L285 Part of the vertical warming may be related to the increased atmospheric heat transport in the Arctic.
L289 had-> has
L300 in high levels-> at high levels
L306 on the control run-> in the control run
L322 For the Arctic
L325 For the Antarctic
L331 the sea ice annual amplitude -> the annual amplitude of sea ice
L332 may -> May
L334 , which contributes
L341-L343 Please rewrite this sentence.
L348-L351 This sentence is too complicated and confusing. Please divide it into two sentences.
L353 Climate Model -> climate model
L352 between->among
L401 near surface -> near-surface
L406 hemispheres -> Hemispheres
L409 albedo-se-> albedo-sea
L411 Despite-> Despite of
L411 showed-> shows
L414 terminal->thermal
L418 presented-> present
L419 add a comma after “13 K”
L425 according to
L427 oceano -> ocean
L429 time and spatial-> temporal and spatial
L429 multiples-> multiple
L431 helps-> help

References:
Konrad H , Shepherd A , Gilbert L , et al. Net retreat of Antarctic glacier grounding lines[J]. Nature Geoscience, 2018, 11(4):1-5.
Schlosser E , Haumann F A , Raphael M N . Atmospheric influences on the anomalous 2016 Antarctic sea ice decay[J]. Cryosphere Discussions, 2017:1-31.
Turner J , Phillips T , Marshall G J , et al. Unprecedented springtime retreat of Antarctic sea ice in 2016[J]. Geophysical Research Letters, 2017.
Honda M , Inoue J , Yamane S . Influence of low Arctic sea-ice minima on anomalously cold Eurasian winters[J]. Geophysical Research Letters, 2009, 36(36):262-275.
Mori M , Watanabe M , Shiogama H , et al. Robust Arctic sea-ice influence on the frequent Eurasian cold winters in past decades[J]. Nature Geoscience, 2014, 7(12):869-873.
Cohen J L , Furtado J C , Barlow M , et al. Asymmetric seasonal temperature trends[J]. Geophysical Research Letters, 2012, 39(4):n/a-n/a.
Zhang J , Tian W , Chipperfield M P , et al. Persistent shift of the Arctic polar vortex towards the Eurasian continent in recent decades[J]. Nature Climate Change, 2016.

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RR by Anonymous Referee #2 (11 May 2020)

Suggestions for revision or reasons for rejection

Even though I find this new version of the manuscript much improved compared with the first version, I have to reiterate my comments from my first revision. I start by saying that, I indeed think that the manuscript addresses a timely and interesting topic that certainly deserves attention from the scientific community. Mainly, I like the “multi-model” comparison of Polar Amplification between the two hemispheres. In this direction, I congratulate the authors.

However, I feel like the authors didn’t address most of my main comments, as follows:

1. In my opinion, the authors are using outdated data sets. We are already in the CMIP6 phase. This means that most of the models have already involved, corrected errors, improved parameterizations, etc, and so generated new data. The CMIP6 data sets are already available, and the computations performed by the authors are not that complex. They could easily be applied to the CMIP6 datasets. I am not saying that the CMIP5 data is not useful, but it would be more useful for the scientific community to see this multi-model comparison with the CMIP6 data. Or, it would be interesting to evaluate what are the differences between the Polar Amplification represented by the models from CMIP5 and CMIP6 phases. To be sure that I am not being impartial, I raised this discussion with other researchers involved in CMIP6 and this is indeed a kind of common sense in the community.

2. It doesn’t help the fact that the authors are using a very limited number of models for a CMIP-like comparison. Since the authors are using relatively old data sets, the minimum that we could expect to see is a broader comparison with all models running the piControl and 4xCO2 experiments. To this point, the authors argued that there is even a Nature Climate Change paper (Harrison et al., 2015) that used only a few CMIP5 models. I don’t see this as a valid argument for the following reasons: (i) this paper was published 5 years ago, so that I am not sure how many models had already contributed to CMIP5 by the date when the authors submitted their manuscript; (ii) back then, the CMIP5 was the current phase of CMIP, while now we are in the sixth phase; (iii) one of the objectives of Harrison et al. (2015) was, as I have mentioned above, to evaluate the “improvements in model performance between CMIP3 and CMIP5 in the simulation of large climate changes” (see their goal n. 4); (v) as far as I understood, Harrison et al. (2015) used data from PMIP, a CMIP-endorsed project so that not all contributors to CMIP5 had run the paleo-simulations. This is not the case for the piControl and 4xCO2 experiments since many of the CMIP5 contributors have provided with those runs.

3. I recall that in the first version of the manuscript the authors had based their conclusions on only three figures and, at this stage, it wasn’t clear whether the manuscript was a short communication or a full article. So, I have suggested that the authors could also use the 1pctCO2 runs. In my opinion, this could bring robustness and make their study more complete. I am not sure what the authors think about this since they didn’t present any answer to this comment, even though I have raised this suggestion both in the main and specific comments. In any case, I am not arguing that these analyses are a “must” for their study, but they would certainly make their manuscript looks like a full-article version (what it is still not clear for me).

Based on the fact that I didn’t see my first comments properly addressed, I am afraid that I can’t give further recommendations on this manuscript’s version. I am sorry that I can’t be more positive at this stage.

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ED: Publish subject to revisions (further review by editor and referees) (11 May 2020) by Igo Paulino

AR by Fernanda Casagrande on behalf of the Authors (08 Jul 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (14 Jul 2020) by Igo Paulino

RR by Anonymous Referee #2 (10 Aug 2020)

ED: Publish subject to technical corrections (10 Aug 2020) by Igo Paulino

AR by Fernanda Casagrande on behalf of the Authors (20 Aug 2020) Author's response Manuscript

Short summary

Polar amplification is possibly one of the most important sensitive indicators of climate change. Our results showed that the polar regions are much more vulnerable to large warming due to an increase in atmospheric CO₂ forcing than the rest of the world, particularly during the cold season. Despite the asymmetry in warming between the Arctic and Antarctic, both poles show systematic polar amplification in all climate models.

An inter-hemispheric seasonal comparison of polar amplification using radiative forcing of a quadrupling CO2 experiment

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Interactive discussion

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An inter-hemispheric seasonal comparison of polar amplification using radiative forcing of a quadrupling CO₂ experiment