the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 11 Apr 2024
Simultaneous Bering Sea and Labrador Sea ice melt extremes in March 2023: A confluence of meteorological events aligned with stratosphere-troposphere interactions
Abstract. Today’s Arctic is characterized by a lengthening of the sea ice melt season, but also by fast and at times unseasonal melt events. Such anomalous melt cases have been identified in Pacific and Atlantic Arctic sector sea ice studies. Through observational analyses, we document an unprecedented, simultaneous marginal ice zone melt event in the Bering Sea and Labrador Sea in March of 2023. Taken independently, variability in the cold season ice edge at synoptic time scales is common. However, such anomalous, short-term ice loss over either region during the climatological sea ice maxima is uncommon, and the tandem ice loss that occurred qualifies this as a rare event. The atmospheric setting that supported the unseasonal melt events was preceded by a sudden stratospheric warming event that, along with ongoing La Niña teleconnections, led to positive tropospheric height anomalies across much of the Arctic and the development of anomalous mid-troposphere ridges over the ice loss regions. These large-scale anticyclonic centers funneled extremely warm and moist airstreams onto the ice causing melt. Further analysis identified the presence of atmospheric rivers within these warm airstreams whose characteristics likely contributed to this bi-regional ice melt event. Whether such a confluence of anomalous wintertime events associated with troposphere-stratosphere coupling may occur more often in a warming Arctic remains a research area ripe for further exploration.
- Preprint
(1369 KB) - Metadata XML
-
Supplement
(804 KB) - BibTeX
- EndNote
Status: closed
-
CC1: 'Comment on egusphere-2024-925', Ruonan Zhang, 18 Jun 2024
The authors investigated the effects of the SSW and La Nina teleconnections on the unseasonal melt events of the tandem ice loss over the Bring and Labrador Seas in March 2023. Associated large-scale anticyclonic anomalies funneled warm and atmospheric rivers to the bi-regional ice melt events. These results are generally interesting, focusing on the combination of stratospheric and La Nina-related tropospheric effects on Arctic surface thermal conditions. However, the atmospheric circulation features and characteristics associated with La Nina are rather unclear. I would like to propose further research into the effects of La Nina on the Arctic.
1. It is quite clear that the SSW occurred around 15 Feb and then propagated downward to the surface around 6 Mar, and the Greenland and Alaska blocking intensified. The first question is, how can we link the SSW to the increased mid-tropospheric blocking? Could the authors provide more evidence of the evolution and pattern of the polar vortex?
2. The La Nina teleconnections are highlighted in the abstract and the main paper, but the associated atmospheric circulation and physical mechanisms are missing. I do not think the present evidence is sufficient to guarantee such a causal link between La Nina and Arctic sea ice melt.
3. Surface air temperature anomalies reach up to 15K over the Labrador and Bering Seas, but the extent and area of sea ice melt is quite small. Could the authors quantify the relative changes in area, extent and concentration?
4. The atmospheric river plays an important role in Arctic warming in March. I am curious about the atmospheric water vapour transports associated with the blockings and the role of water vapour on surface temperature. Is the water vapour converted into snow or rain to lower the temperature, or is the surface warmed by increased longwave radiation?
5. Figure 5: I would suggest that the authors show the climatological daily evolution to facilitate contrasts between the extreme event and the climatology, so that the magnitude of the anomalies is more apparent. I am also curious about the magnitude of the geopotential height and 2m temperature, which reach 500m and 16k respectively. Is this correct?
Citation: https://doi.org/10.5194/egusphere-2024-925-CC1 -
AC1: 'Reply on CC1', Thomas Ballinger, 09 Aug 2024
Please see responses to RC1.
Citation: https://doi.org/10.5194/egusphere-2024-925-AC1
-
AC1: 'Reply on CC1', Thomas Ballinger, 09 Aug 2024
-
RC1: 'Comment on egusphere-2024-925', Anonymous Referee #1, 19 Jun 2024
The authors investigated the effects of the SSW and La Nina teleconnections on the unseasonal melt events of the tandem ice loss over the Bring and Labrador Seas in March 2023. Associated large-scale anticyclonic anomalies funneled warm and atmospheric rivers to the bi-regional ice melt events. These results are generally interesting, focusing on the combination of stratospheric and La Nina-related tropospheric effects on Arctic surface thermal conditions. However, the atmospheric circulation features and characteristics associated with La Nina are rather unclear. I would like to propose further research into the effects of La Nina on the Arctic.
1. It is quite clear that the SSW occurred around 15 Feb and then propagated downward to the surface around 6 Mar, and the Greenland and Alaska blocking intensified. The first question is, how can we link the SSW to the increased mid-tropospheric blocking? Could the authors provide more evidence of the evolution and pattern of the polar vortex?
2. The La Nina teleconnections are highlighted in the abstract and the main paper, but the associated atmospheric circulation and physical mechanisms are missing. I do not think the present evidence is sufficient to guarantee such a causal link between La Nina and Arctic sea ice melt.
3. Surface air temperature anomalies reach up to 15K over the Labrador and Bering Seas, but the extent and area of sea ice melt is quite small. Could the authors quantify the relative changes in area, extent and concentration?
4. The atmospheric river plays an important role in Arctic warming in March. I am curious about the atmospheric water vapour transports associated with the blockings and the role of water vapour on surface temperature. Is the water vapour converted into snow or rain to lower the temperature, or is the surface warmed by increased longwave radiation?
5. Figure 5: I would suggest that the authors show the climatological daily evolution to facilitate contrasts between the extreme event and the climatology, so that the magnitude of the anomalies is more apparent. I am also curious about the magnitude of the geopotential height and 2m temperature, which reach 500m and 16k respectively. Is this correct?
Citation: https://doi.org/10.5194/egusphere-2024-925-RC1 - AC2: 'Reply on RC1', Thomas Ballinger, 09 Aug 2024
-
RC2: 'Comment on egusphere-2024-925', Anonymous Referee #2, 01 Jul 2024
This study examines the rare melting events in the Labrador Sea and Bering Sea in March 2023, a time when the sea ice area typically reaches its maximum during the boreal winter. These melting events are explained by intense moisture transport from lower latitudes, driven by anomalous blocking over high latitudes. The authors also attribute the circulation anomalies to a preceding sudden stratospheric warming (SSW) event and its downward influence. As a case study, the authors effectively link the surface ice melting to stratospheric extremes. However, I have some suggestions and comments regarding the manuscript, as detailed below:
1. I agree with another reviewer's comments on the role of La Niña. The authors did not provide evidence to support this argument. They should either add more evidence regarding La Niña or remove the related conclusion. Considering the manuscript's length, it would be better to remove the arguments about La Niña from the abstract and conclusion. It is still acceptable to mention La Niña among other factors that may have played a role.
2. All figures need improvement. The words/characters are too small.
3. To what extent these two events are extreme? It would be helpful to show a line to denote the 5(1)% percentile or -1.5(-2) sigma.
4. Figure 5 caption: The authors mentioned the black line denoting the mean T2m. Is this an error? It seems to represent the mean values of these variables.
5. It would be great to reorganize the size of the subplots in Figures 6 and 7. The current subplots are too small and not reader-friendly.
6. Lines 35-36: Add Zhang et al. 2018 (10.1126/sciadv.aat6025).
7. Lines 148-149: Related to comments #3. The authors argued that the melting event is ‘unprecedented.’ However, the SIC anomalies ‘did not breach the 5th or 95th percentiles’ and thus do not seem that extreme. Could the authors re-examine the calculation or further clarify?
8. Lines 314-315: The authors did not show any evidence about the downward longwave radiation or surface energy balance in the current study. Given this is in the discussion part, it would be better to cite previous studies here. Some polar AR studies have already presented these results, such as Hegyi and Taylor 2018 (10.1029/2017GL076717), Mattingly et al. 2018 (10.1029/2018JD028714), Wille et al. 2019 (10.1038/s41561-019-0460-1), Frances et al. 2020 (10.1126/sciadv.abc2695), Zhang et al. 2023 (10.1038/s41558-023-01599-3), etc.
Citation: https://doi.org/10.5194/egusphere-2024-925-RC2 - AC3: 'Reply on RC2', Thomas Ballinger, 09 Aug 2024
Status: closed
-
CC1: 'Comment on egusphere-2024-925', Ruonan Zhang, 18 Jun 2024
The authors investigated the effects of the SSW and La Nina teleconnections on the unseasonal melt events of the tandem ice loss over the Bring and Labrador Seas in March 2023. Associated large-scale anticyclonic anomalies funneled warm and atmospheric rivers to the bi-regional ice melt events. These results are generally interesting, focusing on the combination of stratospheric and La Nina-related tropospheric effects on Arctic surface thermal conditions. However, the atmospheric circulation features and characteristics associated with La Nina are rather unclear. I would like to propose further research into the effects of La Nina on the Arctic.
1. It is quite clear that the SSW occurred around 15 Feb and then propagated downward to the surface around 6 Mar, and the Greenland and Alaska blocking intensified. The first question is, how can we link the SSW to the increased mid-tropospheric blocking? Could the authors provide more evidence of the evolution and pattern of the polar vortex?
2. The La Nina teleconnections are highlighted in the abstract and the main paper, but the associated atmospheric circulation and physical mechanisms are missing. I do not think the present evidence is sufficient to guarantee such a causal link between La Nina and Arctic sea ice melt.
3. Surface air temperature anomalies reach up to 15K over the Labrador and Bering Seas, but the extent and area of sea ice melt is quite small. Could the authors quantify the relative changes in area, extent and concentration?
4. The atmospheric river plays an important role in Arctic warming in March. I am curious about the atmospheric water vapour transports associated with the blockings and the role of water vapour on surface temperature. Is the water vapour converted into snow or rain to lower the temperature, or is the surface warmed by increased longwave radiation?
5. Figure 5: I would suggest that the authors show the climatological daily evolution to facilitate contrasts between the extreme event and the climatology, so that the magnitude of the anomalies is more apparent. I am also curious about the magnitude of the geopotential height and 2m temperature, which reach 500m and 16k respectively. Is this correct?
Citation: https://doi.org/10.5194/egusphere-2024-925-CC1 -
AC1: 'Reply on CC1', Thomas Ballinger, 09 Aug 2024
Please see responses to RC1.
Citation: https://doi.org/10.5194/egusphere-2024-925-AC1
-
AC1: 'Reply on CC1', Thomas Ballinger, 09 Aug 2024
-
RC1: 'Comment on egusphere-2024-925', Anonymous Referee #1, 19 Jun 2024
The authors investigated the effects of the SSW and La Nina teleconnections on the unseasonal melt events of the tandem ice loss over the Bring and Labrador Seas in March 2023. Associated large-scale anticyclonic anomalies funneled warm and atmospheric rivers to the bi-regional ice melt events. These results are generally interesting, focusing on the combination of stratospheric and La Nina-related tropospheric effects on Arctic surface thermal conditions. However, the atmospheric circulation features and characteristics associated with La Nina are rather unclear. I would like to propose further research into the effects of La Nina on the Arctic.
1. It is quite clear that the SSW occurred around 15 Feb and then propagated downward to the surface around 6 Mar, and the Greenland and Alaska blocking intensified. The first question is, how can we link the SSW to the increased mid-tropospheric blocking? Could the authors provide more evidence of the evolution and pattern of the polar vortex?
2. The La Nina teleconnections are highlighted in the abstract and the main paper, but the associated atmospheric circulation and physical mechanisms are missing. I do not think the present evidence is sufficient to guarantee such a causal link between La Nina and Arctic sea ice melt.
3. Surface air temperature anomalies reach up to 15K over the Labrador and Bering Seas, but the extent and area of sea ice melt is quite small. Could the authors quantify the relative changes in area, extent and concentration?
4. The atmospheric river plays an important role in Arctic warming in March. I am curious about the atmospheric water vapour transports associated with the blockings and the role of water vapour on surface temperature. Is the water vapour converted into snow or rain to lower the temperature, or is the surface warmed by increased longwave radiation?
5. Figure 5: I would suggest that the authors show the climatological daily evolution to facilitate contrasts between the extreme event and the climatology, so that the magnitude of the anomalies is more apparent. I am also curious about the magnitude of the geopotential height and 2m temperature, which reach 500m and 16k respectively. Is this correct?
Citation: https://doi.org/10.5194/egusphere-2024-925-RC1 - AC2: 'Reply on RC1', Thomas Ballinger, 09 Aug 2024
-
RC2: 'Comment on egusphere-2024-925', Anonymous Referee #2, 01 Jul 2024
This study examines the rare melting events in the Labrador Sea and Bering Sea in March 2023, a time when the sea ice area typically reaches its maximum during the boreal winter. These melting events are explained by intense moisture transport from lower latitudes, driven by anomalous blocking over high latitudes. The authors also attribute the circulation anomalies to a preceding sudden stratospheric warming (SSW) event and its downward influence. As a case study, the authors effectively link the surface ice melting to stratospheric extremes. However, I have some suggestions and comments regarding the manuscript, as detailed below:
1. I agree with another reviewer's comments on the role of La Niña. The authors did not provide evidence to support this argument. They should either add more evidence regarding La Niña or remove the related conclusion. Considering the manuscript's length, it would be better to remove the arguments about La Niña from the abstract and conclusion. It is still acceptable to mention La Niña among other factors that may have played a role.
2. All figures need improvement. The words/characters are too small.
3. To what extent these two events are extreme? It would be helpful to show a line to denote the 5(1)% percentile or -1.5(-2) sigma.
4. Figure 5 caption: The authors mentioned the black line denoting the mean T2m. Is this an error? It seems to represent the mean values of these variables.
5. It would be great to reorganize the size of the subplots in Figures 6 and 7. The current subplots are too small and not reader-friendly.
6. Lines 35-36: Add Zhang et al. 2018 (10.1126/sciadv.aat6025).
7. Lines 148-149: Related to comments #3. The authors argued that the melting event is ‘unprecedented.’ However, the SIC anomalies ‘did not breach the 5th or 95th percentiles’ and thus do not seem that extreme. Could the authors re-examine the calculation or further clarify?
8. Lines 314-315: The authors did not show any evidence about the downward longwave radiation or surface energy balance in the current study. Given this is in the discussion part, it would be better to cite previous studies here. Some polar AR studies have already presented these results, such as Hegyi and Taylor 2018 (10.1029/2017GL076717), Mattingly et al. 2018 (10.1029/2018JD028714), Wille et al. 2019 (10.1038/s41561-019-0460-1), Frances et al. 2020 (10.1126/sciadv.abc2695), Zhang et al. 2023 (10.1038/s41558-023-01599-3), etc.
Citation: https://doi.org/10.5194/egusphere-2024-925-RC2 - AC3: 'Reply on RC2', Thomas Ballinger, 09 Aug 2024
Viewed
| HTML | XML | Total | Supplement | BibTeX | EndNote | |
|---|---|---|---|---|---|---|
| 399 | 89 | 36 | 524 | 44 | 19 | 20 |
- HTML: 399
- PDF: 89
- XML: 36
- Total: 524
- Supplement: 44
- BibTeX: 19
- EndNote: 20
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1