Temporal and spatial evolution of the Antarctic sea ice prior to the September 2012 record maximum extent

Turner, John; Hosking, J. Scott; Phillips, Tony; Marshall, Gareth J.

doi:10.1002/2013gl058371

Cited by 37 publications

(41 citation statements)

References 21 publications

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“…The reduction in sea ice and increase in upper-ocean temperature for all the warming cases (Figs. 5a,c) is in contrast to recent observations showing increased ice production around Antarctica (Parkinson and Cavalieri 2012;Bintanja et al 2013;Turner et al 2013;Blunden et al 2014) and an ongoing cooling trend of Southern Ocean surface waters (e.g., Latif et al 2013;Fan et al 2014). Mechanisms driving these observed trends are poorly understood.…”

Section: A Surface and Sea Ice Responsementioning

confidence: 70%

Sensitivity of Antarctic Bottom Water to Changes in Surface Buoyancy Fluxes

et al. 2015

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The influence of freshwater and heat flux changes on Antarctic Bottom Water (AABW) properties are investigated within a realistic bathymetry coupled ocean-ice sector model of the Atlantic Ocean. The model simulations are conducted at eddy-permitting resolution where dense shelf water production dominates over open ocean convection in forming AABW. Freshwater and heat flux perturbations are applied independently and have contradictory surface responses, with increased upper-ocean temperature and reduced ice formation under heating and the opposite under increased freshwater fluxes. AABW transport into the abyssal ocean reduces under both flux changes, with the reduction in transport being proportional to the net buoyancy flux anomaly south of 608S.Through inclusion of shelf-sourced AABW, a process absent from most current generation climate models, cooling and freshening of dense source water is facilitated via reduced on-shelf/off-shelf exchange flow. Such cooling is propagated to the abyssal ocean, while compensating warming in the deep ocean under heating introduces a decadal-scale variability of the abyssal water masses. This study emphasizes the fundamental role buoyancy plays in controlling AABW, as well as the importance of the inclusion of shelf-sourced AABW within climate models in order to attain the complete spectrum of possible climate change responses.

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Section: A Surface and Sea Ice Responsementioning

confidence: 70%

Sensitivity of Antarctic Bottom Water to Changes in Surface Buoyancy Fluxes

et al. 2015

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“…The positive trends in Antarctic sea ice extent are currently poorly understood and are at odds with climate model forecasts that suggest the sea ice should be declining in response to increasing green- house gases and stratospheric ozone depletion (e.g., Bitz and Polvani, 2012;Sigmond and Fyfe, 2010). However, several modeling studies, such as those used in the phase 5 Coupled Model Intercomparison Project (CMIP5), have suggested that the sea ice increase over the last 36 years remains within the range of intrinsic of internal variability (e.g., Bitz and Polvani, 2012;Turner et al, 2013;Mahlstein et al, 2013;Polvani and Smith, 2013;Swart and Fyfe, 2013). Earlier satellite data from the 1960s and 1970s and data from ship observations suggest periods of high and low sea ice extent and thus high natural variability (Meier et al, 2013b;Gallaher et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

“…Studies point to anomalous short-term wind patterns that both grow and spread out the ice, related to the strength of the Amundsen Sea low pressure (e.g., Turner et al, 2013;Reid et al, 2015;Holland and Kwok, 2012). Other studies suggest meltwater from the underside of floating ice surrounding the continent has risen to the surface and contributed to a slight freshening of the surface ocean (e.g., Bintanja et al, 2013).…”

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confidence: 99%

Mapping and assessing variability in the Antarctic marginal ice zone, pack ice and coastal polynyas in two sea ice algorithms with implications on breeding success of snow petrels

et al. 2016

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Abstract. Sea ice variability within the marginal ice zone (MIZ) and polynyas plays an important role for phytoplankton productivity and krill abundance. Therefore, mapping their spatial extent as well as seasonal and interannual variability is essential for understanding how current and future changes in these biologically active regions may impact the Antarctic marine ecosystem. Knowledge of the distribution of MIZ, consolidated pack ice and coastal polynyas in the total Antarctic sea ice cover may also help to shed light on the factors contributing towards recent expansion of the Antarctic ice cover in some regions and contraction in others. The long-term passive microwave satellite data record provides the longest and most consistent record for assessing the proportion of the sea ice cover that is covered by each of these ice categories. However, estimates of the amount of MIZ, consolidated pack ice and polynyas depend strongly on which sea ice algorithm is used. This study uses two popular passive microwave sea ice algorithms, the NASA Team and Bootstrap, and applies the same thresholds to the sea ice concentrations to evaluate the distribution and variability in the MIZ, the consolidated pack ice and coastal polynyas. Results reveal that the seasonal cycle in the MIZ and pack ice is generally similar between both algorithms, yet the NASA Team algorithm has on average twice the MIZ and half the consolidated pack ice area as the Bootstrap algorithm. Trends also differ, with the Bootstrap algorithm suggesting statistically significant trends towards increased pack ice area and no statistically significant trends in the MIZ. The NASA Team algorithm on the other hand indicates statistically significant positive trends in the MIZ during spring. Potential coastal polynya area and amount of broken ice within the consolidated ice pack are also larger in the NASA Team algorithm. The timing of maximum polynya area may differ by as much as 5 months between algorithms. These differences lead to different relationships between sea ice characteristics and biological processes, as illustrated here with the breeding success of an Antarctic seabird.

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“…The positive sea ice trend might be in part the result of stratospheric ozone depletion that has caused a deepening of the lows in the West Antarctic region (Turner et al 2009;Sigmond and Fyfe 2010;Turner et al 2015). The atmospheric conditions over the area between the Antarctic Peninsula and the Ross Sea are controlled primarily by the Amundsen Sea low (Turner et al 2016), which gives rise to the climatological southerly winds over the Ross and Amundsen Seas.…”

Section: Introductionmentioning

confidence: 99%

“…The atmospheric conditions over the area between the Antarctic Peninsula and the Ross Sea are controlled primarily by the Amundsen Sea low (Turner et al 2016), which gives rise to the climatological southerly winds over the Ross and Amundsen Seas. The interannual variability of the sea ice extent in the Ross Sea sector has been significantly correlated with the strength of the southerly winds over the Ross Sea and the depth of the Amundsen Sea low (Turner et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Positive Trend in the Antarctic Sea Ice Cover and Associated Changes in Surface Temperature

et al. 2017

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The Antarctic sea ice extent has been slowly increasing contrary to expected trends due to global warming and results from coupled climate models. After a record high extent in 2012 the extent was even higher in 2014 when the magnitude exceeded 20 3 10 6 km 2 for the first time during the satellite era. The positive trend is confirmed with newly reprocessed sea ice data that addressed inconsistency issues in the time series. The variability in sea ice extent and ice area was studied alongside surface ice temperature for the 34-yr period starting in 1981, and the results of the analysis show a strong correlation of 20.94 during the growth season and 20.86 during the melt season. The correlation coefficients are even stronger with a one-month lag in surface temperature at 20.96 during the growth season and 20.98 during the melt season, suggesting that the trend in sea ice cover is strongly influenced by the trend in surface temperature. The correlation with atmospheric circulation as represented by the southern annular mode (SAM) index appears to be relatively weak. A case study comparing the record high in 2014 with a relatively low ice extent in 2015 also shows strong sensitivity to changes in surface temperature. The results suggest that the positive trend is a consequence of the spatial variability of global trends in surface temperature and that the ability of current climate models to forecast sea ice trend can be improved through better performance in reproducing observed surface temperatures in the Antarctic region.

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Temporal and spatial evolution of the Antarctic sea ice prior to the September 2012 record maximum extent

Cited by 37 publications

References 21 publications

Sensitivity of Antarctic Bottom Water to Changes in Surface Buoyancy Fluxes

Sensitivity of Antarctic Bottom Water to Changes in Surface Buoyancy Fluxes

Mapping and assessing variability in the Antarctic marginal ice zone, pack ice and coastal polynyas in two sea ice algorithms with implications on breeding success of snow petrels

Positive Trend in the Antarctic Sea Ice Cover and Associated Changes in Surface Temperature

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