Winter warming in West Antarctica caused by central tropical Pacific warming

Ding, Qinghua; Steig, Eric J.; Battisti, David S.; Küttel, Marcel

doi:10.1038/ngeo1129

Cited by 365 publications

(394 citation statements)

References 36 publications

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“…Recent studies have showed that trends in geopotential height and near-surface winds in the ABSL sector region are consistent with such changes (e.g., Turner et al 2009;Ding et al 2011;Schneider et al 2012;Fogt et al 2012b;Holland and Kwok 2012). Owing to its proximity, such circulation changes could be consistent with shifts in the strength and location of the ABSL.…”

Section: Introductionmentioning

confidence: 82%

The Influence of the Amundsen–Bellingshausen Seas Low on the Climate of West Antarctica and Its Representation in Coupled Climate Model Simulations

et al. 2013

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In contrast to earlier studies, the authors describe the climatological deep low pressure system that exists over the South Pacific sector of the Southern Ocean, referred to as the Amundsen-Bellingshausen Seas low (ABSL), in terms of its relative (rather than actual) central pressure by removing the background areaaveraged mean sea level pressure (MSLP). Doing so removes much of the influence of large-scale variability across the ABSL sector region (e.g., due to the southern annular mode), allowing a clearer understanding of ABSL variability and its effect on the regional climate of West Antarctica. Using ECMWF Interim ReAnalysis (ERA-Interim) fields, the annual cycle of the relative central pressure of the ABSL for the period from 1979 to 2011 shows a minimum (maximum) during winter (summer), differing considerably from the earlier studies based on actual central pressure, which suggests a semiannual oscillation. The annual cycle of the longitudinal position of the ABSL is insensitive to the background pressure, and shows it shifting westward from ;2508 to ;2208E between summer and winter, in agreement with earlier studies. The authors demonstrate that ABSL variability, and in particular its longitudinal position, play an important role in controlling the surface climate of West Antarctica and the surrounding ocean by quantifying its influence on key meteorological parameters. Examination of the ABSL annual cycle in 17 CMIP5 climate models run with historical forcing shows that the majority of them have definite biases, especially in terms of longitudinal position, and a correspondingly poor representation of West Antarctic climate.

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Section: Introductionmentioning

confidence: 82%

The Influence of the Amundsen–Bellingshausen Seas Low on the Climate of West Antarctica and Its Representation in Coupled Climate Model Simulations

et al. 2013

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“…3 = sum of PC2 and PC3 from the EOF analysis described in the text; ZPC3 = PC3 of the EOF analysis warming trends in West Antarctica. Although strong winter warming in the Peninsula region (Turner et al 2005) and over West Antarctica has been a focus of other studies (Steig et al 2009;Ding et al 2010 We focused on the large spring warming trend since 1979 across West Antarctica that is evident in nearly all of the temperature datasets, including the in situ records at Scott Base and Faraday/Vernadsky. While we have not evaluated all of the feedback mechanisms and internal and external forcing factors involved, we have shown evidence that the West Antarctic warming is consistent with the regional decline of sea ice in the ABS and with the atmospheric circulation trends over the Southern Oceans.…”

Section: Summary and Discussionmentioning

confidence: 99%

An assessment and interpretation of the observed warming of West Antarctica in the austral spring

2011

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We synthesize variability and trends in multiple analyses of Antarctic near-surface temperature representing several independent source datasets and spatially complete reconstructions, and place these into the broader context of the behavior of other components of the climate system during the past 30-50 years. Along with an annual-mean trend during the past 50 years of about 0.1°C/decade averaged over Antarctica, there is a distinct seasonality to the trends, with insignificant change (and even some cooling) in austral summer and autumn in East Antarctica, contrasting with warming in austral winter and spring. Apart from the Peninsula, the seasonal warming is largest and most significant in West Antarctica in the austral spring since the late 1970s. Concurrent trends in sea ice are independent evidence of the observed warming over West Antarctic, with the decrease in sea ice area in the Amundsen and Bellingshausen Seas congruent with at least 50% of the inland warming of West Antarctica. Trends in near surface winds and geopotential heights over the high-latitude South Pacific are consistent with a role for atmospheric forcing of the sea ice and air temperature anomalies. Most of the circulation trend projects onto the two Pacific South American (PSA) modes of atmospheric circulation variability, while the Southern Annular Mode lacks a positive trend in spring that would otherwise cause a cooling tendency. The largest circulation trend is associated with the PSA-1 mode, a wave-train extending from the tropics to the high Southern latitudes. The PSA-1 mode is significantly correlated with SSTs in the southwestern tropical and subtropical Pacific. The increased SSTs in this region, together with the observed increase in rainfall, suggest that anomalous deep convection has strengthened or increased the occurrence of the Rossby wave-train associated with PSA-1. This hypothesis is supported by results from two ensembles of SST-forced atmospheric general circulation model simulations. Finally, the implications of the seasonality, timing, and spatial patterns of Antarctic temperature trends with respect to interpreting the relative roles of stratospheric ozone depletion, SSTs and increased atmospheric concentrations of greenhouse gasses are discussed.

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“…Around West Antarctica, the transport of sea ice is dominated by the dynamic response to a climatological quasi-stationary low pressure referred to as the Amundsen Sea Low (ASL) [Holland and Kwok, 2012;Hosking et al, 2013;Meehl et al, 2016;Raphael et al, 2016]. This sector is also where robust teleconnections to tropical climate variability occur [Ding et al, 2011;Schneider et al, 2012;Li et al, 2014]. In particular, the El Niño-Southern Oscillation (ENSO) has been strongly linked to changes in sea ice concentration in this region [e.g., Kwok and Comiso, 2002;Stammerjohn et al, 2008;Matear et al, 2015;Kwok et al, 2016] and in other regions within the Southern Ocean [Yuan and Martinson, 2001;Holland et al, 2005].…”

Section: Introductionmentioning

confidence: 99%

The impacts of El Niño on the observed sea ice budget of West Antarctica

Pope

Holland

Orr

et al. 2017

Geophysical Research Letters

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We assess the impact of El Niño‐induced wind changes on seasonal West Antarctic sea ice concentrations using reanalysis data and sea ice observations. A novel ice budget analysis reveals that in autumn a previously identified east‐west dipole of sea ice concentration anomalies is formed by dynamic and thermodynamic processes in response to El Niño‐generated circulation changes. The dipole features decreased (increased) concentration in the Ross Sea (Amundsen and Bellingshausen Seas). Thermodynamic processes and feedback make a substantial contribution to ice anomalies in all seasons. The eastward propagation of this anomaly is partly driven by mean sea ice drift rather than anomalous winds. Our results demonstrate that linkages between sea ice anomalies and atmospheric variability are highly nonlocal in space and time. Therefore, we assert that caution should be applied when interpreting the results of studies that attribute sea ice changes without accounting for such temporally and spatially remote linkages.

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Winter warming in West Antarctica caused by central tropical Pacific warming

Cited by 365 publications

References 36 publications

The Influence of the Amundsen–Bellingshausen Seas Low on the Climate of West Antarctica and Its Representation in Coupled Climate Model Simulations

The Influence of the Amundsen–Bellingshausen Seas Low on the Climate of West Antarctica and Its Representation in Coupled Climate Model Simulations

An assessment and interpretation of the observed warming of West Antarctica in the austral spring

The impacts of El Niño on the observed sea ice budget of West Antarctica

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