Atmospheric winter response to a projected future Antarctic sea-ice reduction: a dynamical analysis

Bader, Jürgen; Flügge, Martin; Kvamstø, Nils Gunnar; Mesquita, Michel D. S.; Voigt, Aiko

doi:10.1007/s00382-012-1507-9

Cited by 32 publications

(37 citation statements)

References 25 publications

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“…Our results suggest an overall weakening of the eddy‐driven jet and negative shift in the SAM index in response to projected Antarctic sea ice loss, particularly in austral spring. These results are in broad agreement with past studies using individual models (Bader et al, ; England et al, ; Menéndez et al, ; Raphael et al, ; Smith et al, ), but we are the first to provide evidence from a multimodel ensemble. The weakening of the eddy‐driven jet and negative SAM in response to sea ice loss counteract, but only partially offset, the projected jet strengthening and positive SAM in response to increased CO 2 (Figures S1 and S2).…”

Section: Discussionsupporting

confidence: 93%

“…Raphael et al () suggested that negative summer sea ice anomalies were linked to a more negative Southern Annular Mode (SAM) index and vice versa. Studies examining the atmospheric response to projected Antarctic sea ice loss have revealed contrasting results, with Kidston et al () finding no significant impacts, whereas Bader et al () and Menéndez et al () both found an equatorward shift of the tropospheric jet. More recently, England et al () used the WACCM4 model to compare impacts of Arctic and Antarctic sea ice loss.…”

Section: Introductionmentioning

confidence: 98%

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Multimodel Analysis of the Atmospheric Response to Antarctic Sea Ice Loss at Quadrupled CO₂

Ayres

Screen

2019

Geophysical Research Letters

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Antarctic sea ice cover is projected to significantly decrease by the end of the twenty‐first century if greenhouse gas concentrations continue to rise, with potential consequences for Southern Hemisphere weather and climate. Here we examine the atmospheric response to projected Antarctic sea ice loss at quadrupled CO2, inferred from 11 Coupled Model Intercomparison Project phase 5 models. Our study is the first multimodel analysis of the atmospheric response to Antarctic sea ice loss. Projected sea ice loss enhances the negative phase of the Southern Annular Mode, which slightly damps the positive Southern Annular Mode response to increased CO2, particularly in spring. The negative Southern Annular Mode response largely reflects a weakening of the eddy‐driven jet, and to a lesser extent, an equatorward shift of the jet. Sea ice loss induces near‐surface warming over the high‐latitude Southern Ocean, but warming does not penetrate over the Antarctic continent. In spring, we find multimodel evidence for a weakened polar stratospheric vortex in response to sea ice loss.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 98%

Multimodel Analysis of the Atmospheric Response to Antarctic Sea Ice Loss at Quadrupled CO₂

Ayres

Screen

2019

Geophysical Research Letters

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“…The meridional and vertical transport of vapor is along zonal mean moist isentropes (θ e ) that are largely shaped by local air mass temperature and topography in Antarctica, especially for water vapor originating from the individual SO subsectors ( Fig. 8; see also Bailey et al, 2019). As a result, a large portion (up to 70 % for the zonal mean) of the vapor below 700 mbar comes from the Southern Ocean source tag, which also contributes a significant amount (10 %-40 %) to vapor in the middle troposphere (700-400 mbar).…”

Section: Transport Pathways Of Water To Antarcticamentioning

confidence: 99%

Influence of sea-ice anomalies on Antarctic precipitation using source attribution in the Community Earth System Model

et al. 2020

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Abstract. We conduct sensitivity experiments using a general circulation model that has an explicit water source tagging capability forced by prescribed composites of pre-industrial sea-ice concentrations (SICs) and corresponding sea surface temperatures (SSTs) to understand the impact of sea-ice anomalies on regional evaporation, moisture transport and source–receptor relationships for Antarctic precipitation in the absence of anthropogenic forcing. Surface sensible heat fluxes, evaporation and column-integrated water vapor are larger over Southern Ocean (SO) areas with lower SICs. Changes in Antarctic precipitation and its source attribution with SICs have a strong spatial variability. Among the tagged source regions, the Southern Ocean (south of 50∘ S) contributes the most (40 %) to the Antarctic total precipitation, followed by more northerly ocean basins, most notably the South Pacific Ocean (27%), southern Indian Ocean (16 %) and South Atlantic Ocean (11 %). Comparing two experiments prescribed with high and low pre-industrial SICs, respectively, the annual mean Antarctic precipitation is about 150 Gt yr−1 (or 6 %) more in the lower SIC case than in the higher SIC case. This difference is larger than the model-simulated interannual variability in Antarctic precipitation (99 Gt yr−1). The contrast in contribution from the Southern Ocean, 102 Gt yr−1, is even more significant compared to the interannual variability of 35 Gt yr−1 in Antarctic precipitation that originates from the Southern Ocean. The horizontal transport pathways from individual vapor source regions to Antarctica are largely determined by large-scale atmospheric circulation patterns. Vapor from lower-latitude source regions takes elevated pathways to Antarctica. In contrast, vapor from the Southern Ocean moves southward within the lower troposphere to the Antarctic continent along moist isentropes that are largely shaped by local ambient conditions and coastal topography. This study also highlights the importance of atmospheric dynamics in affecting the thermodynamic impact of sea-ice anomalies associated with natural variability on Antarctic precipitation. Our analyses of the seasonal contrast in changes of basin-scale evaporation, moisture flux and precipitation suggest that the impact of SIC anomalies on regional Antarctic precipitation depends on dynamic changes that arise from SIC–SST perturbations along with internal variability. The latter appears to have a more significant effect on the moisture transport in austral winter than in summer.

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“…Regional westerlies can also drive changes in upper-ocean heat storage and sea ice formation by affecting Ekman pumping and thus the sea ice extent (e.g., Turner et al, 2013b). The southern annular mode, which dominates the variability of the large-scale atmospheric 5 circulation in the Southern Hemisphere, has been found to co-vary with tropical SST variability (e.g., Ding et al, 2012) and respond to SIC changes (e.g., Menéndez et al, 1999;Bader et al, 2013;Smith et al, 2017). The Amundsen-Bellingshausen Seas Low (ABSL), which plays an important role in bringing warm/moist air into the Bellingshausen Sea and Antarctic Peninsula region and moving cold/dry air equatorward through the Ross Sea region, strongly influences winds, near-surface temperature, 10 precipitation and SIC over the Amundsen-Bellingshausen Seas (e.g., Hosking et al, 2013).…”

Section: Changes In Meridional Transport and Circulation Patternsmentioning

confidence: 99%

Influence of Sea Ice Anomalies on Antarctic Precipitation Using Source Attribution

Wang

Fyke

Lenaerts

et al. 2019

Preprint

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Abstract. We conduct sensitivity experiments using a climate model that has an explicit water source tagging capability forced by prescribed composites of sea ice concentrations (SIC) and corresponding SSTs to understand the impact of sea ice anomalies on regional evaporation, moisture transport, and source–receptor relationships for precipitation over Antarctica. Surface sensible heat fluxes, evaporation, and column-integrated water vapor are larger over Southern Ocean (SO) areas with lower SIC, but changes in Antarctic precipitation and its source attribution with SICs reflect a strong spatial variability. Among the tagged source regions, the Southern Ocean (south of 50° S) contributes the most (40 %) to the Antarctic total precipitation, followed by more northerly ocean basins, most notably the S. Pacific Ocean (27 %), S. Indian Ocean (16 %) and S. Atlantic Ocean (11 %). The annual mean Antarctic precipitation is about 150 Gt/year more in the “low” SIC case than in the “high” SIC case. This difference is larger than the model-simulated interannual variability of Antarctic precipitation (99 Gt/year). The contrast in contribution from the S. Ocean, 102 Gt/year, is even more significant, compared to the interannual variability of 35 Gt/year in Antarctic precipitation that originates from the S. Ocean. The horizontal transport pathways from individual vapor source regions to Antarctica are largely determined by large-scale atmospheric circulation patterns. Vapor from lower latitude source regions takes elevated pathways to Antarctica. In contrast, vapor from the Southern Ocean moves southward within the lower troposphere to the Antarctic continent, so the contribution of nearby sources also depends on regional coastal topography. The impact of sea ice anomalies on regional Antarctic precipitation also depends on atmospheric circulation changes that result from the prescribed composite SIC/SST perturbations. In particular, regional wind anomalies along with surface evaporation changes determine regional shifts in the zonal and meridional moisture fluxes that can explain some of the resultant precipitation changes.

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Atmospheric winter response to a projected future Antarctic sea-ice reduction: a dynamical analysis

Cited by 32 publications

References 25 publications

Multimodel Analysis of the Atmospheric Response to Antarctic Sea Ice Loss at Quadrupled CO₂

Multimodel Analysis of the Atmospheric Response to Antarctic Sea Ice Loss at Quadrupled CO₂

Influence of sea-ice anomalies on Antarctic precipitation using source attribution in the Community Earth System Model

Influence of Sea Ice Anomalies on Antarctic Precipitation Using Source Attribution

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Atmospheric winter response to a projected future Antarctic sea-ice reduction: a dynamical analysis

Cited by 32 publications

References 25 publications

Multimodel Analysis of the Atmospheric Response to Antarctic Sea Ice Loss at Quadrupled CO2

Multimodel Analysis of the Atmospheric Response to Antarctic Sea Ice Loss at Quadrupled CO2

Influence of sea-ice anomalies on Antarctic precipitation using source attribution in the Community Earth System Model

Influence of Sea Ice Anomalies on Antarctic Precipitation Using Source Attribution

Contact Info

Product

Resources

About

Multimodel Analysis of the Atmospheric Response to Antarctic Sea Ice Loss at Quadrupled CO₂

Multimodel Analysis of the Atmospheric Response to Antarctic Sea Ice Loss at Quadrupled CO₂