the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 15 Aug 2022
Mid-Holocene reinforcement of North Atlantic atmospheric circulation variability from a western Baltic lake sediment record
Abstract. Knowledge about timing, amplitude and spatial gradients of Holocene environmental variability in the Circum-Baltic region is key to understand its responses to ongoing climate change. Based on a multi-dating and proxy approach, we reconstruct changes in productivity from TOC contents in sediments of Lake Kälksjön (KKJ) in west-central Sweden spanning the last 9612 (+255/-144) years. An exception is the period from AD 1878 until today, in which sedimentation was dominated by anthropogenic lake level lowering and land use. In-lake productivity was higher during periods of warmer winters with shortened ice cover and prolonged growing seasons. A multi-millennial increase in productivity throughout the last ~9600 years is associated with progressively warmer winters in north-western Europe, likely triggered by the coinciding increase in Northern Hemisphere winter insolation. Decadal to centennial periods of higher productivity in KKJ correspond to warmer winters during a more positive North Atlantic Oscillation (NAO) polarity, as reconstructed for the last 5200 years. In consequence, we assume our decadal to centennial productivity record from KKJ sediments for the complete ~9600 years to provide a qualitative record of NAO polarity. A shift towards higher productivity variability at ~5450 cal. a BP is hypothesized to reflect a reinforcement of NAO-like atmospheric circulation variability, possibly driven by more vigorous changes in North Atlantic deep water formation.
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Preprint
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2022-582', Anonymous Referee #1, 18 Sep 2022
Comment on Mid-Holocene reinforcement of North Atlantic atmospheric circulation variability from a western Baltic lake sediment record by Markus Czymzik et al.
This is a very interesting study which attempts to provide insights into the North Atlantic Oscillation (NAO) variability throughout most of the Holocene. The detailed sedimentology from lake Kalksjon, west-central Sweden, is excellent and provides some justification for its use as a qualitative reconstruction of the NAO. Overall, I found the manuscript well written and will be of high interest for the paleoclimate community studying the climate during the Holocene for this region. It is therefore suitable for Climate of the Past. However, to assess this archive as a reconstructed “qualitative” record of the NAO, I believe there needs to be further examinations.
Major comments:
Different NAO reconstructions show periods of coherency and often no coherency at all. This is partly because the NAO itself exhibits non-stationary behavior, so the use of one single location may not capture the whole variability. One aspect that may have been overlooked in this paper is the other existing NAO proxies. Have you explored other records that may be sensitive to large-scale and long-term NAO fluctuations? That said, from 1800BP to the present, the NAO from Olsen et al. (2012) and the TOC record don’t seem to match quite well, but perhaps if you plot different reconstructed NAO, a better co-variability (correlation) may be seen. I am thinking of speleothems in Europe and North Africa as well as the new one from Becker et al. (2020). See also Wassenburg et al. 2016 Nat Geosci, Baker et al. 2015, etc.
Figure 12 shows the relationship between paleo NAO (Olsen et al. 2012) and the TOC content in the studied lake. When sampling both records to the lowest resolution of the corresponding record; do you find any significant correlations? Same comment for the Siberian High.
Also, the lack of coherence between your record and other NAO proxies could be explained by other mode of variability that may have been more persistent in the past. The Scandinavian Blocking, for example, accounts for ~27% of the winter North Atlantic variability. A persistent Scandinavian Blocking in winter would translate to cooler conditions in the region, thereby presumably increased ice cover time (in turn less productivity). Any thoughts on this? I suggest to add more discussion around line 345.
Some other minor comments:
Figure 3: Given you are dealing with decadal to centennial scale variability, I think an average (monthly?) of temperature and precipitation would improve visualization.
Figure 4 shows the composite with the XRF cluster stratigraphy. It should be located after figure 7 (PCA of the elements).
Figure 4: Add average temporal resolution for each cluster, i.e., mm/year
Figure 10: the sharp decline in TOC falls within 4.2k BP. Do you consider that your proxy responded to the 4.2k event?
Figure 12: we don’t see much the Trouet et al. NAO, the color is too pale. Also, why not the selection of the Ortega et al. reconstructed NAO?
Figure 12: the lines of the SH index are outside the x-axis.
Figure 13: the spectral peaks don’t seem to match quite well, perhaps a cross-spectral analysis would give something better. I would suggest moving this to the supplement.
Line 89: could you provide more information as to how the grain-size was extracted?
Section 3.3: provide information on how many thin-sections were produced.
Section 3.5: Why no pollen analysis on other SDU?
Section 4.3: Add a Table showing the matrix correlation between µ-XRF data
Line 104: 3s is deem low. Is this a typo?
Line 105: why only these elements? For example, why is Ca omitted?
Line 106: How did you build the µ-XRF composite? Elements often decrease (increase) their values at both edge of the sediment sections. Did you remove those data?
Line 239: There is no Ca profile showing these peaks. Maybe add into supplement.
Line 364-365: Please rephrase
Citation: https://doi.org/10.5194/egusphere-2022-582-RC1 -
EC1: 'Reply on RC1', Denis-Didier Rousseau, 18 Sep 2022
Dear authors,
Reviewer #1 has posted his review pointing to 3 major comments. Please take the opportunity of the discussion phase to post a short to these comments so that a dialog could start with reviewer #1.
All the very best
denis-didier Rousseau
CP Co-Editor in chief
Citation: https://doi.org/10.5194/egusphere-2022-582-EC1 - AC2: 'Reply on RC1', Markus Czymzik, 02 Nov 2022
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EC1: 'Reply on RC1', Denis-Didier Rousseau, 18 Sep 2022
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RC2: 'Comment on egusphere-2022-582', Anonymous Referee #2, 20 Sep 2022
Comment on Mid-Holocene reinforcement of North Atlantic atmospheric circulation variability from a western Baltic lake sediment record by Markus Czymzik et al
I agree with reviewer 1 that this is a very interesting and well-written paper that provides new insight into NOA variability using a Swedish lake record. I am, however, not an expert in NAO and NAO variability so I have focused my review on other aspects of the paper.
Comments:
Line 18 Maybe a minor comment, but I think that LKJ would be a better acronym than KKJ
Line 19 I prefer CE (Common Era) rather than AD
Line 42 Here it might be useful if you define what you mean with the western Baltic region (or the western Baltic Sea region?). There are at least ten different definition of the “Baltic Region” in Wikipedia
Line 55 I checked the Swedish Land Survey online maps and long. 13°03’E is more correct.
Line 59 west
Line 63 Figure 3 shows daily temperatures and precipitations, not mean monthly temperatures, see also comment by Rev. 1
Line 105 I agree with Rev. 1, why was not e.g. Zr and Ca analysed
Line 228 I would use “concentrations of the artificial radionuclides” rather than “contents”
Line 238 See comment by Rev. 1. Was Ca measured after all?
Line 266 I was slightly confused by the discussion about the isolation of the lake basin from Ancient Lake Vänern. I have not read the Risberg et al paper in any detail, but the uplift history of the area is complicated with evidence of irregular postglacial isostatic uplift. Hence, the comment that the isolation of L. Skjutsbolstjärnet located at a similar location (and what is meant by that?) and height supports your isolation point must be clarified (or deleted?). The isolation age of L. Skjutsbolstjärnet is c. 9600 uncalibrated C14 years which calibrates to c. 10,900 cal a BP
Line 269 cal is missing before “a BP” (Stanton et al. 2010)
Line 313 typo? Should be east of L. Kälksjön
Line 318 My alternative interpretation of the TOC contents would be “a sharp increase until ca 4500 cal a BP with a drop at ca. 5300 cal a BP”, i.e. the increase continues another 1000 years, followed by more stable values until recent times. I would also add δ13C to Figure 10.
Line 331 Does this refer to winter or annual temperatures, precipitation and windiness?
Line 341 I am not certain that the reference to Almquist-Jacobson is 100% correct here. Almquist-Jacobson’s sites are situated in an area that may have been settled by humans later than the river and lake valleys in Värmland. There are archaeological findings north and north-west of Torsby dating back to the early Neolithic (3800-3300 BC)
Line 364-374 Here you should also discuss proxy records from Sweden showing climate shifts at this time, e.g. the peat record from Store Mosse (Kylander et al., 2013; QSR) and lake level records from L. Bysjön (Digerfeldt, 1988; Boreas). These could also be shown to Fig. 12.
Line 546 Change Väners to Vänern
Table 1 If possible, give weights and type of material (e.g. terrestrial or lacustrine plant remains?)
Figure 2 Give the source of the historic document. Museum, library?
Figure 4 Sediment deposition units. Give the age range for each SDU, if possible, not only the onset
Citation: https://doi.org/10.5194/egusphere-2022-582-RC2 -
EC2: 'Reply on RC2', Denis-Didier Rousseau, 07 Oct 2022
Dear authors,
Reviewer #2 has posted his review pointing different issues in your manuscript. Once more, please take the opportunity of the discussion phase to post a short to these comments so that a dialog could start with reviewer #2.
All the very best
denis-didier Rousseau
CP Co-Editor in chief
Citation: https://doi.org/10.5194/egusphere-2022-582-EC2 - AC3: 'Reply on RC2', Markus Czymzik, 02 Nov 2022
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EC2: 'Reply on RC2', Denis-Didier Rousseau, 07 Oct 2022
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AC1: 'Comment on egusphere-2022-582', Markus Czymzik, 10 Oct 2022
We thank both referees for their positive and constructive comments on our manuscript.
We agree with Referee #1 about the non-stationary behavior of NAO-like changes in atmospheric circulation through time that are difficult to reconstruct, based on individual paleoclimate archives. As suggested by Referee #1 we will compare a range of NAO reconstructions with our TOC record from KKJ sediments and extend the connection discussion.
We are grateful about the valuable comments of Referee #2 on ice sheet dynamics during the last deglaciation, human impact and additional Holocene paleoclimate records from the KJJ region. We will develop the manuscript based on this new information.
We will modify the manuscript including both referees’ minor comments.
Citation: https://doi.org/10.5194/egusphere-2022-582-AC1
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2022-582', Anonymous Referee #1, 18 Sep 2022
Comment on Mid-Holocene reinforcement of North Atlantic atmospheric circulation variability from a western Baltic lake sediment record by Markus Czymzik et al.
This is a very interesting study which attempts to provide insights into the North Atlantic Oscillation (NAO) variability throughout most of the Holocene. The detailed sedimentology from lake Kalksjon, west-central Sweden, is excellent and provides some justification for its use as a qualitative reconstruction of the NAO. Overall, I found the manuscript well written and will be of high interest for the paleoclimate community studying the climate during the Holocene for this region. It is therefore suitable for Climate of the Past. However, to assess this archive as a reconstructed “qualitative” record of the NAO, I believe there needs to be further examinations.
Major comments:
Different NAO reconstructions show periods of coherency and often no coherency at all. This is partly because the NAO itself exhibits non-stationary behavior, so the use of one single location may not capture the whole variability. One aspect that may have been overlooked in this paper is the other existing NAO proxies. Have you explored other records that may be sensitive to large-scale and long-term NAO fluctuations? That said, from 1800BP to the present, the NAO from Olsen et al. (2012) and the TOC record don’t seem to match quite well, but perhaps if you plot different reconstructed NAO, a better co-variability (correlation) may be seen. I am thinking of speleothems in Europe and North Africa as well as the new one from Becker et al. (2020). See also Wassenburg et al. 2016 Nat Geosci, Baker et al. 2015, etc.
Figure 12 shows the relationship between paleo NAO (Olsen et al. 2012) and the TOC content in the studied lake. When sampling both records to the lowest resolution of the corresponding record; do you find any significant correlations? Same comment for the Siberian High.
Also, the lack of coherence between your record and other NAO proxies could be explained by other mode of variability that may have been more persistent in the past. The Scandinavian Blocking, for example, accounts for ~27% of the winter North Atlantic variability. A persistent Scandinavian Blocking in winter would translate to cooler conditions in the region, thereby presumably increased ice cover time (in turn less productivity). Any thoughts on this? I suggest to add more discussion around line 345.
Some other minor comments:
Figure 3: Given you are dealing with decadal to centennial scale variability, I think an average (monthly?) of temperature and precipitation would improve visualization.
Figure 4 shows the composite with the XRF cluster stratigraphy. It should be located after figure 7 (PCA of the elements).
Figure 4: Add average temporal resolution for each cluster, i.e., mm/year
Figure 10: the sharp decline in TOC falls within 4.2k BP. Do you consider that your proxy responded to the 4.2k event?
Figure 12: we don’t see much the Trouet et al. NAO, the color is too pale. Also, why not the selection of the Ortega et al. reconstructed NAO?
Figure 12: the lines of the SH index are outside the x-axis.
Figure 13: the spectral peaks don’t seem to match quite well, perhaps a cross-spectral analysis would give something better. I would suggest moving this to the supplement.
Line 89: could you provide more information as to how the grain-size was extracted?
Section 3.3: provide information on how many thin-sections were produced.
Section 3.5: Why no pollen analysis on other SDU?
Section 4.3: Add a Table showing the matrix correlation between µ-XRF data
Line 104: 3s is deem low. Is this a typo?
Line 105: why only these elements? For example, why is Ca omitted?
Line 106: How did you build the µ-XRF composite? Elements often decrease (increase) their values at both edge of the sediment sections. Did you remove those data?
Line 239: There is no Ca profile showing these peaks. Maybe add into supplement.
Line 364-365: Please rephrase
Citation: https://doi.org/10.5194/egusphere-2022-582-RC1 -
EC1: 'Reply on RC1', Denis-Didier Rousseau, 18 Sep 2022
Dear authors,
Reviewer #1 has posted his review pointing to 3 major comments. Please take the opportunity of the discussion phase to post a short to these comments so that a dialog could start with reviewer #1.
All the very best
denis-didier Rousseau
CP Co-Editor in chief
Citation: https://doi.org/10.5194/egusphere-2022-582-EC1 - AC2: 'Reply on RC1', Markus Czymzik, 02 Nov 2022
-
EC1: 'Reply on RC1', Denis-Didier Rousseau, 18 Sep 2022
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RC2: 'Comment on egusphere-2022-582', Anonymous Referee #2, 20 Sep 2022
Comment on Mid-Holocene reinforcement of North Atlantic atmospheric circulation variability from a western Baltic lake sediment record by Markus Czymzik et al
I agree with reviewer 1 that this is a very interesting and well-written paper that provides new insight into NOA variability using a Swedish lake record. I am, however, not an expert in NAO and NAO variability so I have focused my review on other aspects of the paper.
Comments:
Line 18 Maybe a minor comment, but I think that LKJ would be a better acronym than KKJ
Line 19 I prefer CE (Common Era) rather than AD
Line 42 Here it might be useful if you define what you mean with the western Baltic region (or the western Baltic Sea region?). There are at least ten different definition of the “Baltic Region” in Wikipedia
Line 55 I checked the Swedish Land Survey online maps and long. 13°03’E is more correct.
Line 59 west
Line 63 Figure 3 shows daily temperatures and precipitations, not mean monthly temperatures, see also comment by Rev. 1
Line 105 I agree with Rev. 1, why was not e.g. Zr and Ca analysed
Line 228 I would use “concentrations of the artificial radionuclides” rather than “contents”
Line 238 See comment by Rev. 1. Was Ca measured after all?
Line 266 I was slightly confused by the discussion about the isolation of the lake basin from Ancient Lake Vänern. I have not read the Risberg et al paper in any detail, but the uplift history of the area is complicated with evidence of irregular postglacial isostatic uplift. Hence, the comment that the isolation of L. Skjutsbolstjärnet located at a similar location (and what is meant by that?) and height supports your isolation point must be clarified (or deleted?). The isolation age of L. Skjutsbolstjärnet is c. 9600 uncalibrated C14 years which calibrates to c. 10,900 cal a BP
Line 269 cal is missing before “a BP” (Stanton et al. 2010)
Line 313 typo? Should be east of L. Kälksjön
Line 318 My alternative interpretation of the TOC contents would be “a sharp increase until ca 4500 cal a BP with a drop at ca. 5300 cal a BP”, i.e. the increase continues another 1000 years, followed by more stable values until recent times. I would also add δ13C to Figure 10.
Line 331 Does this refer to winter or annual temperatures, precipitation and windiness?
Line 341 I am not certain that the reference to Almquist-Jacobson is 100% correct here. Almquist-Jacobson’s sites are situated in an area that may have been settled by humans later than the river and lake valleys in Värmland. There are archaeological findings north and north-west of Torsby dating back to the early Neolithic (3800-3300 BC)
Line 364-374 Here you should also discuss proxy records from Sweden showing climate shifts at this time, e.g. the peat record from Store Mosse (Kylander et al., 2013; QSR) and lake level records from L. Bysjön (Digerfeldt, 1988; Boreas). These could also be shown to Fig. 12.
Line 546 Change Väners to Vänern
Table 1 If possible, give weights and type of material (e.g. terrestrial or lacustrine plant remains?)
Figure 2 Give the source of the historic document. Museum, library?
Figure 4 Sediment deposition units. Give the age range for each SDU, if possible, not only the onset
Citation: https://doi.org/10.5194/egusphere-2022-582-RC2 -
EC2: 'Reply on RC2', Denis-Didier Rousseau, 07 Oct 2022
Dear authors,
Reviewer #2 has posted his review pointing different issues in your manuscript. Once more, please take the opportunity of the discussion phase to post a short to these comments so that a dialog could start with reviewer #2.
All the very best
denis-didier Rousseau
CP Co-Editor in chief
Citation: https://doi.org/10.5194/egusphere-2022-582-EC2 - AC3: 'Reply on RC2', Markus Czymzik, 02 Nov 2022
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EC2: 'Reply on RC2', Denis-Didier Rousseau, 07 Oct 2022
-
AC1: 'Comment on egusphere-2022-582', Markus Czymzik, 10 Oct 2022
We thank both referees for their positive and constructive comments on our manuscript.
We agree with Referee #1 about the non-stationary behavior of NAO-like changes in atmospheric circulation through time that are difficult to reconstruct, based on individual paleoclimate archives. As suggested by Referee #1 we will compare a range of NAO reconstructions with our TOC record from KKJ sediments and extend the connection discussion.
We are grateful about the valuable comments of Referee #2 on ice sheet dynamics during the last deglaciation, human impact and additional Holocene paleoclimate records from the KJJ region. We will develop the manuscript based on this new information.
We will modify the manuscript including both referees’ minor comments.
Citation: https://doi.org/10.5194/egusphere-2022-582-AC1
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Markus Czymzik
Rik Tjallingii
Birgit Plessen
Peter Feldens
Martin Theuerkauf
Matthias Moros
Markus J. Schwab
Carla K. M. Nantke
Silvia Pinkerneil
Achim Brauer
Helge W. Arz
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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